BSC6900+GSM+Technical+Description(V900R012C01 03)

BSC6900 GSMV900R012C01

Technical Description

Issue 03

Date 2010-09-20

HUAWEI TECHNOLOGIES CO., LTD.

Copyright © Huawei Technologies Co., Ltd. 2010. All rights reserved.No part of this document may be reproduced or transmitted in any form or by any means without prior writtenconsent of Huawei Technologies Co., Ltd. Trademarks and Permissions

and other Huawei trademarks are trademarks of Huawei Technologies Co., Ltd.All other trademarks and trade names mentioned in this document are the property of their respective holders. NoticeThe purchased products, services and features are stipulated by the contract made between Huawei and thecustomer. All or part of the products, services and features described in this document may not be within thepurchase scope or the usage scope. Unless otherwise specified in the contract, all statements, information,and recommendations in this document are provided "AS IS" without warranties, guarantees or representationsof any kind, either express or implied.

The information in this document is subject to change without notice. Every effort has been made in thepreparation of this document to ensure accuracy of the contents, but all statements, information, andrecommendations in this document do not constitute the warranty of any kind, express or implied.

Huawei Technologies Co., Ltd.Address: Huawei Industrial Base

Bantian, LonggangShenzhen 518129People's Republic of China

Website: http://www.huawei.com

Email: [email protected]

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http://www.huawei.com

mailto:[email protected]

About This Document

PurposeThis document describes the structure, working principles, signal flows, and transmission andnetworking of the BSC6900. It helps the reader understand the implementation and workingprinciples of the BSC6900.

Product VersionThe following table lists the product version related to the document.

Product Name Product Version

BSC6900 V900R012C01

Intended AudienceThis document is intended for:

l Network planners

l System engineers

l Field engineers

Organization1 Changes in the BSC6900 GSM Technical Description

This chapter describes the changes in the BSC6900 GSM Technical Description .

2 Hardware Configuration Modes

The BSC6900 supports flexible hardware configuration modes. The hardware configurationmode varies according to the scenario.

3 Overall Structure

This chapter describes the interactions between the modules in the BSC6900.

BSC6900 GSMTechnical Description About This Document


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4 Working Principles

This chapter describes the working principles of the BSC6900 in the following ways: powersupply, environment monitoring, clock synchronization, and OM.

5 Signal Flow

The BSC6900 signal flow consists of the user-plane signal flow, control-plane signal flow, andOM signal flow.

6 Transmission and Networking

The transmission and networking between the BSC6900 and other NEs can be classified intothe following types: transmission and networking on the A/Gb interface, on the Abis interface,on the Ater interface, and on the Pb interface.

7 Parts Reliability

The BSC6900 guarantees its operation reliability by means of board redundancy and portredundancy.

ConventionsSymbol Conventions

The symbols that may be found in this document are defined as follows.

Symbol Description

Indicates a hazard with a high level of risk, which if notavoided,will result in death or serious injury.

Indicates a hazard with a medium or low level of risk, whichif not avoided, could result in minor or moderate injury.

Indicates a potentially hazardous situation, which if notavoided,could result in equipment damage, data loss,performance degradation, or unexpected results.

Indicates a tip that may help you solve a problem or savetime.

Provides additional information to emphasize or supplementimportant points of the main text.

General Conventions

The general conventions that may be found in this document are defined as follows.

Convention Description

Times New Roman Normal paragraphs are in Times New Roman.

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Boldface Names of files, directories, folders, and users are inboldface. For example, log in as user root.

Italic Book titles are in italics.

Courier New Examples of information displayed on the screen are inCourier New.

Command Conventions

The command conventions that may be found in this document are defined as follows.


Boldface The keywords of a command line are in boldface.

Italic Command arguments are in italics.

[ ] Items (keywords or arguments) in brackets [ ] are optional.

{ x | y | ... } Optional items are grouped in braces and separated byvertical bars. One item is selected.

[ x | y | ... ] Optional items are grouped in brackets and separated byvertical bars. One item is selected or no item is selected.

{ x | y | ... }* Optional items are grouped in braces and separated byvertical bars. A minimum of one item or a maximum of allitems can be selected.

[ x | y | ... ]* Optional items are grouped in brackets and separated byvertical bars. Several items or no item can be selected.

GUI Conventions

The GUI conventions that may be found in this document are defined as follows.


Boldface Buttons, menus, parameters, tabs, window, and dialog titlesare in boldface. For example, click OK.

> Multi-level menus are in boldface and separated by the ">"signs. For example, choose File > Create > Folder.

Keyboard Operations

The keyboard operations that may be found in this document are defined as follows.

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Format Description

Key Press the key. For example, press Enter and press Tab.

Key 1+Key 2 Press the keys concurrently. For example, pressing Ctrl+Alt+A means the three keys should be pressed concurrently.

Key 1, Key 2 Press the keys in turn. For example, pressing Alt, A meansthe two keys should be pressed in turn.

Mouse Operations

The mouse operations that may be found in this document are defined as follows.

Action Description

Click Select and release the primary mouse button without movingthe pointer.

Double-click Press the primary mouse button twice continuously andquickly without moving the pointer.

Drag Press and hold the primary mouse button and move thepointer to a certain position.

About This DocumentBSC6900 GSM


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Contents

About This Document...................................................................................................................iii

1 Changes in the BSC6900 GSM Technical Description.......................................................1-1

2 Hardware Configuration Modes.............................................................................................2-1

3 Overall Structure........................................................................................................................3-13.1 Switching Subsystem......................................................................................................................................3-53.2 Service Processing Subsystem........................................................................................................................3-93.3 Interface Processing Subsystem....................................................................................................................3-103.4 Clock Synchronization Subsystem................................................................................................................3-123.5 OM Subsystem..............................................................................................................................................3-13

4 Working Principles....................................................................................................................4-14.1 Power Supply Principle...................................................................................................................................4-24.2 Environment Monitoring Principle.................................................................................................................4-34.3 Clock Synchronization Principle.....................................................................................................................4-6

4.3.1 Clock Sources.........................................................................................................................................4-64.3.2 Structure of the clock synchronization subsystem.................................................................................4-74.3.3 Clock Synchronization Process..............................................................................................................4-9

4.4 OM Principle.................................................................................................................................................4-114.4.1 Dual OM Plane.....................................................................................................................................4-124.4.2 OM Network........................................................................................................................................4-134.4.3 Active/Standby Workspaces................................................................................................................4-144.4.4 Data Configuration Management.........................................................................................................4-164.4.5 Security Management...........................................................................................................................4-204.4.6 Performance Management....................................................................................................................4-234.4.7 Alarm Management..............................................................................................................................4-254.4.8 Loading Management...........................................................................................................................4-264.4.9 Upgrade Management..........................................................................................................................4-304.4.10 BTS Loading Management................................................................................................................4-324.4.11 BTS Upgrade Management................................................................................................................4-33

5 Signal Flow..................................................................................................................................5-15.1 User-Plane Signal Flow...................................................................................................................................5-2

5.1.1 CBC Signal Flow...................................................................................................................................5-2

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5.1.2 GSM CS Signal Flow.............................................................................................................................5-35.1.3 GSM PS Signal Flow.............................................................................................................................5-8

5.2 Control-Plane Signal Flow............................................................................................................................5-105.2.1 Signaling Flow on the A Interface.......................................................................................................5-105.2.2 Signaling Flow on the Abis Interface...................................................................................................5-125.2.3 Signaling Flow on the Gb Interface.....................................................................................................5-145.2.4 Signaling Flow on the Pb Interface......................................................................................................5-14

5.3 OM Signal Flow............................................................................................................................................5-15

6 Transmission and Networking................................................................................................6-16.1 Transmission and Networking on the A/Gb Interface.....................................................................................6-2

6.1.1 TDM-Based Networking on the A/Gb Interface....................................................................................6-26.1.2 IP-Based Networking on the A/Gb Interface.........................................................................................6-3

6.2 Transmission and Networking on the Abis Interface......................................................................................6-46.2.1 TDM-Based Networking on the Abis Interface.....................................................................................6-46.2.2 IP-Based Networking on the Abis Interface...........................................................................................6-5

6.3 Transmission and Networking on the Ater Interface......................................................................................6-76.3.1 TDM-Based Networking on the Ater Interface......................................................................................6-76.3.2 IP-Based Networking on the Ater Interface...........................................................................................6-8

6.4 Transmission and Networking on the Pb Interface.........................................................................................6-8

7 Parts Reliability..........................................................................................................................7-17.1 Concepts Related to Parts Reliability..............................................................................................................7-2

7.1.1 Backup....................................................................................................................................................7-27.1.2 Resource Pool.........................................................................................................................................7-37.1.3 Port Trunking.........................................................................................................................................7-37.1.4 Port Load Sharing...................................................................................................................................7-4

7.2 Board Redundancy..........................................................................................................................................7-47.2.1 Backup of EIUa Boards..........................................................................................................................7-57.2.2 Backup of OIUa Boards.........................................................................................................................7-57.2.3 Backup of PEUa Boards.........................................................................................................................7-67.2.4 Backup of POUc Boards........................................................................................................................7-77.2.5 Backup of SCUa Boards........................................................................................................................7-87.2.6 Backup of TNUa Boards........................................................................................................................7-87.2.7 Backup of FG2a/FG2c Boards...............................................................................................................7-97.2.8 Backup of GCUa/GCGa Boards..........................................................................................................7-107.2.9 Backup of GOUa/GOUc Boards..........................................................................................................7-117.2.10 Backup of OMUa/OMUb Boards......................................................................................................7-127.2.11 Backup of XPUa/XPUb Boards.........................................................................................................7-137.2.12 Resource Pool of DPUa/DPUc/DPUd Boards...................................................................................7-13

7.3 Port Redundancy...........................................................................................................................................7-147.3.1 Optical Port Backup.............................................................................................................................7-147.3.2 FE/GE Port Backup..............................................................................................................................7-157.3.3 Port Load Sharing.................................................................................................................................7-15

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7.3.4 Port Trunking.......................................................................................................................................7-16

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Figures

Figure 3-1 Structure of the host software.............................................................................................................3-2Figure 3-2 Structure of the OMU software..........................................................................................................3-2Figure 3-3 Logical structure of MPS/EPS............................................................................................................3-3Figure 3-4 Logical structure of TCS.................................................................................................................... 3-3Figure 3-5 Position of the switching subsystem in the MPS/EPS........................................................................3-5Figure 3-6 Position of the switching subsystem in the TCS................................................................................ 3-6Figure 3-7 Network topologies between subracks...............................................................................................3-7Figure 3-8 Interconnections between subracks through the crossover cables between the SCUa boards (MPS/EPS)...............................................................................................................................................................................3-7Figure 3-9 Interconnections between subracks through the crossover cables between the SCUa boards (TCS)...............................................................................................................................................................................3-8Figure 3-10 Interconnections between subracks through the inter-TNUa cables (MPS/EPS).............................3-8Figure 3-11 Interconnections between subracks through the inter-TNUa cables (TCS)..................................... 3-9Figure 3-12 Service processing subsystem.......................................................................................................... 3-9Figure 3-13 Position of the interface processing subsystem in the MPS/EPS...................................................3-11Figure 3-14 Position of the interface processing subsystem in the TCS............................................................3-11Figure 3-15 Position of the clock synchronization subsystem in the BSC6900 system....................................3-12Figure 3-16 Position of the OM subsystem in the BSC6900 system.................................................................3-13Figure 4-1 Power input part of the BSC6900.......................................................................................................4-2Figure 4-2 Working principle of power monitoring.............................................................................................4-3Figure 4-3 Working principle of fan monitoring..................................................................................................4-4Figure 4-4 Working principle of environment monitoring...................................................................................4-5Figure 4-5 Structure of the clock synchronization subsystem..............................................................................4-7Figure 4-6 Structure of the clock synchronization subsystem..............................................................................4-8Figure 4-7 Process of clock synchronization in the MPS/EPS (1).......................................................................4-9Figure 4-8 Process of clock synchronization in the MPS/EPS (2).....................................................................4-10Figure 4-9 Process of clock synchronization in the TCS...................................................................................4-10Figure 4-10 Dual OM plane...............................................................................................................................4-12Figure 4-11 Structure of the OM network..........................................................................................................4-13Figure 4-12 Principle of effective mode configuration......................................................................................4-17Figure 4-13 Principle of ineffective mode configuration...................................................................................4-17Figure 4-14 Check of the data consistency between the OMU and the host boards..........................................4-19Figure 4-15 Process of collecting performance measurement data periodically................................................4-24Figure 4-16 Alarm management process............................................................................................................4-25

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Figure 4-17 Working principle of the alarm box................................................................................................4-26Figure 4-18 Loading process (1)........................................................................................................................4-27Figure 4-19 Loading process (2)........................................................................................................................4-28Figure 4-20 Loading process (3)........................................................................................................................4-30Figure 4-21 Upgrade through the OM network..................................................................................................4-31Figure 4-22 Upgrade process.............................................................................................................................4-31Figure 5-1 Signal flow from CBC-BSC to Abis..................................................................................................5-2Figure 5-2 GSM CS signal flow (1).....................................................................................................................5-3Figure 5-3 GSM CS signal flow (2).....................................................................................................................5-4Figure 5-4 GSM CS signal flow (3).....................................................................................................................5-4Figure 5-5 GSM CS signal flow (4).....................................................................................................................5-5Figure 5-6 GSM CS signal flow (5).....................................................................................................................5-6Figure 5-7 GSM CS signal flow (6).....................................................................................................................5-6Figure 5-8 GSM CS signal flow (7).....................................................................................................................5-7Figure 5-9 GSM CS signal flow (8).....................................................................................................................5-8Figure 5-10 GSM PS signal flow (1)....................................................................................................................5-9Figure 5-11 GSM PS signal flow (2)....................................................................................................................5-9Figure 5-12 Signaling flow on the A interface in A over TDM mode (BM/TC separated)...............................5-11Figure 5-13 Signaling flow on the A interface in A over TDM mode (BM/TC combined)..............................5-11Figure 5-14 Signaling flow on the A interface in A over IP mode....................................................................5-12Figure 5-15 Signaling flow on the Abis interface in Abis over TDM mode......................................................5-13Figure 5-16 Signaling flow on the Abis interface in Abis over IP mode...........................................................5-13Figure 5-17 Signaling flow on the Gb interface.................................................................................................5-14Figure 5-18 Signaling flow on the Pb interface.................................................................................................5-15Figure 5-19 OM signal flow (BM/TC separated)...............................................................................................5-16Figure 5-20 OM signal flow (BM/TC combined)..............................................................................................5-17Figure 6-1 TDM-based networking on the A interface in local TCS mode.........................................................6-2Figure 6-2 TDM-based networking on the A interface in remote TCS mode......................................................6-2Figure 6-3 TDM-based networking on the Gb interface......................................................................................6-3Figure 6-4 IP over E1 networking on the A interface..........................................................................................6-3Figure 6-5 IP over Ethernet networking on the A/Gb interface...........................................................................6-4Figure 6-6 TDM-based networking on the Abis interface...................................................................................6-5Figure 6-7 IP over E1 Networking.......................................................................................................................6-5Figure 6-8 IP over Ethernet networking (layer 2)................................................................................................6-6Figure 6-9 IP over Ethernet networking (layer 3)................................................................................................6-6Figure 6-10 TDM-based networking on the Ater interface..................................................................................6-7Figure 6-11 IP-based networking on the Ater interface.......................................................................................6-8Figure 6-12 TDM-based networking on the Pb interface.....................................................................................6-8

FiguresBSC6900 GSM


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Tables

Table 3-1 Components of the BSC6900 cabinet..................................................................................................3-1Table 4-1 Definitions of the user rights..............................................................................................................4-20Table 4-2 Types of logs......................................................................................................................................4-22

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1 Changes in the BSC6900 GSM TechnicalDescription

This chapter describes the changes in the BSC6900 GSM Technical Description .

03 (2010-09-20)This is the third commercial release of V900R012C01.

Compared with issue 02 (2010-06-21), this issue does not include any new topics.

Compared with issue 02 (2010-06-21), this issue incorporates the following changes:

Topic Change Description

7.2.12 Resource Pool of DPUa/DPUc/DPUd Boards

The description of the resource pool ismodified.

Compared with issue 02 (2010-06-21), this issue does not exclude any topics.

02 (2010-06-21)This is the second commercial release of V900R012C01.

Compared with issue 01 (2010-04-10), this issue includes the following new topics:

l 7 Parts Reliability

Compared with issue 01 (2010-04-10), this issue incorporates the following changes:

Content Description

4.4.5 Security Management The requirement for password setting isadded.

Compared with issue 01 (2010-04-10), this issue does not exclude any topics.

BSC6900 GSMTechnical Description 1 Changes in the BSC6900 GSM Technical Description


1-1

01 (2010-04-10)This is the first commercial release of V900R012C01.

Compared with issue 04 (2010-01-30) of V900R011C00, this issue does not include any newtopics.

Compared with issue 04 (2010-01-30) of V900R011C00, this issue does not incorporate anychanges.

Compared with issue 04 (2010-01-30) of V900R011C00, this issue does not exclude any topics.

1 Changes in the BSC6900 GSM Technical DescriptionBSC6900 GSM


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2 Hardware Configuration Modes

The BSC6900 supports flexible hardware configuration modes. The hardware configurationmode varies according to the scenario.

Learn the following concepts for a better understanding of the BSC6900.

BM/TC

The main processing subrack (MPS) and extended processing subrack (EPS) are collectivelyknown as basic module (BM) subrack. The transcoder subrack (TCS) is known as TC subrack.

Main TCS

The TCS that forwards the OM signals to other TCSs is called the main TCS. All other TCSsare called extension TCSs.

The main TCS is determined by both the cable connections and the data configuration. For detailsof the cable connections, see switching subsystem.

Subrack Configuration Modes

The BSC6900 subracks can be configured in three modes:l BM/TC separated

In BM/TC separated mode, the BSC6900 is configured with the MPS, EPS, and TCS (localor remote).Characteristics: In this mode, the installation location of the TCS is flexible. The TCS canbe installed in the transcoder rack (TCR) and be placed on the CN side, thus saving thetransmission resources between the BSC6900 and the CN. Alternatively, the TCS can beinstalled in the same cabinet as the MPS or EPS and be placed on the BSC6900 side.

l BM/TC combinedIn BM/TC combined mode, the boards of the TCS are installed in the MPS or in the EPS,with the subrack names unchanged.Characteristics: The BSC6900 in this mode has higher hardware integration than in BM/TC separated mode, When the capacity is the same, the BSC6900 in this mode has fewercabinets and subracks.

l A over IP

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In A over IP mode, layer 3 (network layer) of the protocol stack on the A interface adoptsthe IP protocol. In this case, the BSC6900 is configured with the MPS and EPS but notwith the TCS. The TC function is performed by the Media Gateway (MGW).Characteristics: In this mode, the BSC6900 has fewer cabinets and subracks. TheBSC6900 must be interconnected with a specific MGW.

One BSC6900 uses only one configuration mode.

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3 Overall Structure

About This Chapter

This chapter describes the interactions between the modules in the BSC6900.

Physical StructureThe BSC6900 cabinet consists of power distribution boxes and subracks, as listed in Table3-1.

Table 3-1 Components of the BSC6900 cabinet

Component Configuration

MPS One MPS must be configured.

EPS Zero to five EPSs can be configured.

TCS Zero to four TCSs can be configured.

Independent fan subrack Each cabinet must be configured with one independent fansubrack.

Power distribution box Each cabinet must be configured with one power distributionbox.

NOTE

If customers purchase also the Nastar product of Huawei, customers need to install the SAU board in the MPSor EPS of the BSC6900 cabinet (the SAU board occupies two slots that work in active/standby mode). For detailson how to install the SAU board, how to install the software on the SAU board, and how to maintain the SAUboard, see the SAU User Guide of Nastar documents.

Software StructureThe software of the BSC6900 has a distributed architecture. It is classified into the host softwareand OMU software.

BSC6900 GSMTechnical Description 3 Overall Structure


3-1

l Host softwareThe host software is distributed on the service boards. It consists of the operating system,middleware, and application software. See Figure 3-1.

Figure 3-1 Structure of the host software

– Operating system

The VxWorks real-time embedded operating system runs on each service board.– Middleware

The Versatile Protocol Platform (VPP) and the Virtual Operating System (VOS)function as the middleware. The middleware enables the upper-layer applicationsoftware to be independent from the lower-layer operating system so that softwarefunctions can be transplanted between different platforms.

– Application softwareBoards of different types can be installed with different application software. Theapplication software is classified into radio resource processing software, resourcecontrol-plane processing software, base station management software, andconfiguration maintenance management software.

l OMU softwareThe Operation and Maintenance Unit (OMU) software runs on the OMUa board, OMUbboard, and GBAM. The OMU is responsible for the operation and maintenance of theBSC6900. The OMU software consists of the operating system and the OMU applicationsoftware. See Figure 3-2.

Figure 3-2 Structure of the OMU software

– Operating system

The Dopra Linux, Suse Linux, or Windows Server 2003 operating system is used.– OMU application software

The OMU application software runs on the lower-level operating system and providesvarious service processes, including the LMT process, fault diagnosis process, andauthentication process.

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Logical StructureFigure 3-3 and Figure 3-4 show the logical structure of the BSC6900.

Figure 3-3 Logical structure of MPS/EPS

Figure 3-4 Logical structure of TCS

The TCS that forwards the OM signals to other TCSs is called the main TCS.



3-3

The channel for the TCS and the MPS to exchange information varies according to the locationof the TCS: local or remote.

l In local TCS mode, the SCUa board in the main TCS is connected to the SCUa board inthe MPS through the crossover cable.

l In remote TCS mode, the TCS is located in the TCR, which is separate from the cabinetthat houses the MPS/EPS. The main TCS and the MPS are connected through the cablebetween the Ater interface boards.

SubsystemsLogically, the BSC6900 consists of the following five subsystems:

3.1 Switching SubsystemThe switching subsystem performs switching of traffic data, signaling, and OM signals.

3.2 Service Processing SubsystemThe BSC6900 service processing subsystem performs the control functions defined in the 3GPPprotocols and processes services of the BSC6900.

3.3 Interface Processing SubsystemThe interface processing subsystem provides transmission ports and resources, processestransport network messages, and enables interaction between the BSC6900 internal data andexternal data.

3.4 Clock Synchronization SubsystemThe clock synchronization subsystem provides clock signals for the BSC6900 and providesreference clock signals for base stations.

3.5 OM SubsystemThe OM subsystem enables the management and maintenance of the BSC6900 in the followingscenarios: routine maintenance, emergency maintenance, upgrade, and capacity expansion.




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3.1 Switching SubsystemThe switching subsystem performs switching of traffic data, signaling, and OM signals.

Position of the Switching Subsystem in the BSC6900 SystemThe switching subsystem consists of logical modules of two types: MAC switching and TDMswitching. Figure 3-5 and Figure 3-6 show the position of the switching subsystem in the MPS/EPS and TCS respectively, with the modules highlighted in apricot.

Figure 3-5 Position of the switching subsystem in the MPS/EPS



3-5

Figure 3-6 Position of the switching subsystem in the TCS

Functionsl Provides intra-subrack Medium Access Control (MAC) switching

l Provides intra-subrack Time Division Multiplexing (TDM) switching

l Provides inter-subrack MAC switching and TDM switching

l Distributes clock signals to the service processing boards

Hardware Involved

The switching subsystem consists of the SCUa boards, TNUa boards, high-speed backplanechannels in each subrack, crossover cables between SCUa boards, and inter-TNUa cables.

Network Topologies Between Subracks

The BSC6900 subracks can be connected in the star or mesh topology. In Figure 3-7, (1) and(2) represent the star and mesh topologies respectively, where the dots represent subracks.

l Star topology

One node functions as the center node and it is connected to each of the other nodes. Thecommunication between the other nodes must be switched by the center node.

l Mesh topology

There is a connection between every two nodes. When any node is out of service, thecommunication between other nodes is not affected.




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Figure 3-7 Network topologies between subracks

In the switching subsystem of the BSC6900, the star topology is established among the MACswitching logical modules, and the mesh topology is established among the TDM switchinglogical modules.

Inter-Subrack Connection

The MAC switching logical modules switch the IP-based traffic data, OM signals, and signaling.The switching is performed by the SCUa boards and the Ethernet cables between the SCUaboards. The inter-subrack connections related to MAC switching can be classified into thefollowing types:

l Interconnections between the MPS and the EPSs

The MPS functions as the main subrack, and a maximum of three EPSs function asextension subracks. The star interconnections between the MPS and the EPSs areestablished through the Ethernet cables between the SCUa boards, as shown in Figure3-8.

l Interconnections between the TCSs

One TCS functions as the main subrack, and a maximum of three TCSs function asextension subracks. The star interconnections between the TCSs are established throughthe Ethernet cables between the SCUa boards, as shown in Figure 3-9.

Figure 3-8 Interconnections between subracks through the crossover cables between the SCUaboards (MPS/EPS)



3-7

Figure 3-9 Interconnections between subracks through the crossover cables between the SCUaboards (TCS)

The TDM switching logical modules switch the TDM-based traffic data. The switching isperformed by the TNUa boards and the inter-TNUa cables. The inter-subrack connections relatedto TDM switching can be classified into the following types:

l Interconnections between the MPS and the EPSsThe mesh interconnections between the MPS and the EPSs are established through theinter-TNUa cables, as shown in Figure 3-10.

l Interconnections between the TCSsThe mesh interconnections between the TCSs are established through the inter-TNUacables, as shown in Figure 3-11.

Figure 3-10 Interconnections between subracks through the inter-TNUa cables (MPS/EPS)




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Figure 3-11 Interconnections between subracks through the inter-TNUa cables (TCS)

3.2 Service Processing SubsystemThe BSC6900 service processing subsystem performs the control functions defined in the 3GPPprotocols and processes services of the BSC6900.

Position of the Service Processing Subsystem in the BSC6900 System

The service processing subsystem mainly consists of two logical modules: BSC control plane(CP) and BSC user plane (UP). Figure 3-12 shows the position of the service processingsubsystem in the BSC6900 system, with the modules highlighted in apricot.

NOTE

For details about the definitions of CP and UP, see 5 Signal Flow.

Figure 3-12 Service processing subsystem



3-9

FunctionsThe service processing subsystem performs the following functions:

l User data transfer

l System admission control

l Radio channel ciphering and deciphering

l Data integrity protection

l Mobility management

l Radio resource management and control

l Cell broadcast service control

l System information and user message tracing

l Data volume reporting

l Radio access management

l CS service processing

l PS service processing

Service processing subsystems communicate with each other through the switching subsystemto form a resource pool and perform tasks cooperatively. They can be increased as required,according to the linear superposition principle, thereby improving the service processingcapability of the BSC6900.

Hardware InvolvedThe service processing subsystem consists of the XPUa, XPUb, DPUc, and DPUd boards. TheXPUa and XPUb boards process signaling. The DPUc and DPUd boards process services.

3.3 Interface Processing SubsystemThe interface processing subsystem provides transmission ports and resources, processestransport network messages, and enables interaction between the BSC6900 internal data andexternal data.

Position of the Interface Processing Subsystem in the BSC6900 SystemThe interface processing subsystem consists of two types of interfaces: IP interfaces and TDMinterfaces. Figure 3-13 and Figure 3-14 show the position of the interface processing subsystemin the BSC6900 system, with the interfaces highlighted in apricot.




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Figure 3-13 Position of the interface processing subsystem in the MPS/EPS

Figure 3-14 Position of the interface processing subsystem in the TCS

Functionsl The interface processing subsystem provides the following types of IP and TDM interfaces.

– E1/T1 electrical ports



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– STM-1 optical ports– FE/GE electrical ports– GE optical ports

l The interface processing subsystem processes transport network messages and, also hidesdifferences between them within the BSC6900.

l On the uplink, the interface processing subsystem terminates transport network messagesat the interface boards. It also transmits the user plane, control plane, and managementplane datagrams to the corresponding service processing boards. The processing of thesignal flow on the downlink is the reverse of the processing of the signal flow on the uplink.

Hardware InvolvedThe interface processing subsystem consists of the Abis, A, Ater, Gb, and Pb interface boards.

3.4 Clock Synchronization SubsystemThe clock synchronization subsystem provides clock signals for the BSC6900 and providesreference clock signals for base stations.

Position of the Clock Synchronization Subsystem in the BSC6900 SystemFigure 3-15 shows the position of the clock synchronization subsystem in the BSC6900 system,with the clock module highlighted in apricot.

Figure 3-15 Position of the clock synchronization subsystem in the BSC6900 system

FunctionsThe clock synchronization subsystem provides the following clock sources for the BSC6900and ensures the reliability of the clock signals:




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l Building Integrated Timing Supply System (BITS) clock

l Global Positioning System (GPS) clock

l External 8 kHz clock

l LINE clock

The BSC6900 provides reference clock sources for base stations. Clock signals are transmittedfrom the BSC6900 to base stations over the Abis interface.

Hardware Involved

The clock synchronization subsystem consists of the GCUa/GCGa board.

3.5 OM SubsystemThe OM subsystem enables the management and maintenance of the BSC6900 in the followingscenarios: routine maintenance, emergency maintenance, upgrade, and capacity expansion.

Position of the OM Subsystem in the BSC6900 System

Figure 3-16 shows the position of the OM subsystem in the BSC6900 system, with the OMmodule highlighted in apricot.

Figure 3-16 Position of the OM subsystem in the BSC6900 system

Functions

The OM subsystem provides:

l 4.4.4 Data Configuration Management



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l 4.4.5 Security Management

l 4.4.6 Performance Management

l 4.4.7 Alarm Management

l 4.4.8 Loading Management

l 4.4.9 Upgrade Management

l 4.4.10 BTS Loading Management

l 4.4.11 BTS Upgrade Management

Hardware InvolvedThe OM subsystem consists of the OMUa board, OMUb board, or GBAM.




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4 Working Principles

About This Chapter

This chapter describes the working principles of the BSC6900 in the following ways: powersupply, environment monitoring, clock synchronization, and OM.

4.1 Power Supply PrincipleThe power supply subsystem of the BSC6900 adopts the dual-circuit design and point-by-pointmonitoring solution. It consists of the power input part and the power distribution part.

4.2 Environment Monitoring PrincipleThe environment monitoring subsystem of the BSC6900 comprises the power distribution boxand the environment monitoring parts in each subrack. This subsystem monitors and controlsthe power supply, fans, and operating environment.

4.3 Clock Synchronization PrincipleThe clock synchronization subsystem of the BSC6900 consists of the GCUa/GCGa board andthe clock processing units of each subrack. It provides clock signals for the BSC6900 andreference clocks for base stations.

4.4 OM PrincipleOM is performed in the following scenarios: routine maintenance, emergency maintenance,troubleshooting, device upgrade, and capacity expansion. In addition, OM can be performed torapidly adjust device status.

BSC6900 GSMTechnical Description 4 Working Principles


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4.1 Power Supply PrincipleThe power supply subsystem of the BSC6900 adopts the dual-circuit design and point-by-pointmonitoring solution. It consists of the power input part and the power distribution part.

The power supply subsystem of the BSC6900 consists of the -48 V DC power system, DC powerdistribution frame (PDF), and DC power distribution box (PDB) at the top of the cabinet.

If a site has heavy traffic or more than two switching systems, two or more independent powersupply systems should be provided. In the case of a communication center, independent powersupply systems should be configured on different floors to supply power to different equipmentrooms.

Power Input PartThe power input part leads the power from the DC PDF to the PDB in the cabinet. It consists ofthe DC PDF, PDB, and cables between them.

Figure 4-1 shows the power input part of the BSC6900.

Figure 4-1 Power input part of the BSC6900

NOTE

The DC PDF and the DC power distribution panel are not regarded as the components of the BSC6900.

The working principle of the power input part is as follows:

l The DC PDF provides each cabinet with dual two-route -48 V DC inputs and one route forPGND connection.

l Typically, the two power inputs work concurrently. If one power input is faulty, the otherpower input continues to supply power to the system to ensure stable operation. You canrectify the faulty power input without interrupting the services, thereby ensuring theoptimum reliability and availability of the power supply subsystem.

Power Distribution PartThe power distribution part distributes power from the PDB to various components in the cabinet.It comprises the PDB, power distribution switches, and various components in the cabinet.

4 Working PrinciplesBSC6900 GSM



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The working principle of the power distribution part is as follows:

l The PDB performs lightning protection and overcurrent protection on the dual two-route-48 V DC inputs. Then, it supplies power to all the components in the cabinet.

l The PDB monitors each input in real time. After the PDB detects abnormal power supply,it reports the relevant alarms to the OMU. The OMU, then, forwards the alarms to the LMTor M2000.

l The power distribution varies according to the type of cabinet. For details, see Connectionsof Power Cables and PGND Cables in the Cabinet.

4.2 Environment Monitoring PrincipleThe environment monitoring subsystem of the BSC6900 comprises the power distribution boxand the environment monitoring parts in each subrack. This subsystem monitors and controlsthe power supply, fans, and operating environment.

NOTE

The physical entity of the OMU can be the OMUa board, OMUb board, or GBAM. The following takes theOMUa board as an example to describe environment monitoring.

Power MonitoringPower monitoring involves monitoring the power subsystem in real time, reporting the operatingstatus of the power supply, and generating alarms when faults occur.

Figure 4-2 shows the working principle of power monitoring.

Figure 4-2 Working principle of power monitoring

The power monitoring process is as follows:

1. The PAMU in the power distribution box monitors the operating status of the powerdistribution box and sends the monitoring signals to the signal transfer board through theserial port.

2. The signal transfer board transmits the power monitoring signals to the independent fansubrack at the bottom of the cabinet through the monitoring signal cable of the power



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distribution box. Then, the fan subrack forwards the power monitoring signals to the activeSCUa board in the power monitoring subrack.

3. The SCUa board processes the monitoring signals. If faults occur, the SCUa board generatesalarms and reports the alarms to the OMUa board. The OMUa board then forwards thealarms to the LMT or M2000.

Fan MonitoringFan monitoring involves monitoring the operating status of the fans in real time and adjustingthe speed of the fans based on the temperature in the subrack.

Each subrack is configured with a built-in fan box. The temperature sensor next to the air outletcan detect the temperature in the subrack.

Besides the built-in fan box in the subrack, there is an independent fan subrack at the bottom ofthe cabinet. This improves the heat dissipation capability of the cabinet.

Figure 4-3 shows the working principle of fan monitoring.

Figure 4-3 Working principle of fan monitoring

The fan monitoring process is as follows:

1. The built-in fan box in the subrack and the fan monitoring unit PFCU in the independentfan subrack monitor the operating status of the fans in real time and reports the monitoringsignals to the signal transfer board through the serial port.

2. The signal transfer board transmits the monitoring signals to the active SCUa board.l In the case of built-in fan box in the subrack, the signal transfer board transmits the

monitoring signals to the active SCUa board through the backplane of the subrack.l In the case of independent fan subrack, the signal transfer board transmits the monitoring

signals to the active SCUa board in the fan monitoring subrack through the monitoringsignal cable.

3. The SCUa board processes the monitoring signals. If faults occur, the SCUa board generatesalarms and reports them to the OMUa board. The OMUa board then forwards the alarmsto the LMT or M2000.




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Environment Monitoring

Environment monitoring involves monitoring the temperature, humidity, operating voltage, doorstatus, water damage, smoke, and infrared. The environment monitoring function is performedby the Environment Monitor Units (EMUs).

Figure 4-4 shows the working principle of environment monitoring.

Figure 4-4 Working principle of environment monitoring

If the power distribution box can transfer signals, the environment monitoring process is asfollows:

1. The sensors monitor the environment in real time and send the monitoring signals to theEMU.

2. The EMU sends the monitoring signals to the power distribution box through the serialcable.

3. The signal transfer board in the power distribution box transmits the monitoring signals tothe active SCUa board in the power monitoring subrack through the monitoring signal cableof the power distribution box.

4. The active SCUa board in the power monitoring subrack transmits the monitoring signalsto the SCUa board in the MPS through the Ethernet cables between the SCUa boards.

5. The SCUa board in the MPS processes the monitoring signals. If faults occur, the SCUaboard generates alarms and reports the alarms to the OMUa board. The OMUa board thenforwards the alarms to the LMT or M2000.

If the power distribution box cannot transfer signals, the environment monitoring process is asfollows:

1. The sensors monitor the environment in real time and send the monitoring signals to theEMU.



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2. The EMU sends the monitoring signals to the active SCUa board in the lowest subrackthrough the serial cable.

3. The active SCUa board in the lowest subrack transmits the monitoring signals to the SCUaboard in the MPS through the Ethernet cables between the SCUa boards.

4. The SCUa board in the MPS processes the monitoring signals. If faults occur, the SCUaboard generates alarms and reports the alarms to the OMUa board. The OMUa board thenforwards the alarms to the LMT or M2000.

4.3 Clock Synchronization PrincipleThe clock synchronization subsystem of the BSC6900 consists of the GCUa/GCGa board andthe clock processing units of each subrack. It provides clock signals for the BSC6900 andreference clocks for base stations.

4.3.1 Clock SourcesThe BSC6900 can use the following clock sources: Building Integrated Timing Supply System(BITS) clock, external 8 kHz clock, LINE clock, and Global Positioning System (GPS) clock.

4.3.2 Structure of the clock synchronization subsystemThe clock synchronization subsystem consists of the clock board, backplanes, clock cablesbetween subracks, and clock module in each board.

4.3.3 Clock Synchronization ProcessThe BSC6900 processes external clock signals before sending them to its boards. The clocksynchronization process varies slightly from one subrack to another.

4.3.1 Clock SourcesThe BSC6900 can use the following clock sources: Building Integrated Timing Supply System(BITS) clock, external 8 kHz clock, LINE clock, and Global Positioning System (GPS) clock.

External ClocksThe external clocks of the BSC6900 are of two types:l BITS Clock

– The BITS clock signals are of three types: 2 MHz, 2 Mbit/s, and 1.5 Mbit/s. The 2 MHzand 2 Mbit/s clock signals are E1 clock signals, and the 1.5 Mbit/s clock signals are T1clock signals.

– The BITS clock has two input modes: BITS0 and BITS1. BITS0 and BITS1 correspondto the CLKIN0 and CLKIN1 ports on the GCUa/GCGa board respectively. TheBSC6900 obtains the BITS clock signals through the CLKIN0 or CLKIN1 port.

l External 8 kHz ClockThrough the COM1 port on the GCUa/GCGa board, the BSC6900 obtains 8 kHz standardclock signals from an external device.

LINE ClockThe LINE clock is an 8 kHz clock that is transmitted from an interface board in the MPS to theGCUa/GCGa board through the backplane channel. The LINE clock has two input modes:LINE0 and LINE1.




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NOTE

LINE0 and LINE1 correspond to backplane channel 1 and backplane channel 2 respectively.

GPS ClockThe GPS clock provides 1 Pulse Per Second (PPS) clock signals. The BSC6900 obtains the GPSclock signals from the GPS system. The GCGa board is configured with a GPS card, and theBSC6900 receives the GPS signals at the ANT port on the GCGa board.

NOTE

The GCUa board is not configured with a GPS card. Therefore, when the BSC6900 is configured with the GCUaboard instead of the GCGa board, the GPS clock is unavailable to the BSC6900.

Local OscillatorIf the BSC6900 fails to obtain any external clock, the BSC6900 can obtain its working clocksignals from the local oscillator.

4.3.2 Structure of the clock synchronization subsystemThe clock synchronization subsystem consists of the clock board, backplanes, clock cablesbetween subracks, and clock module in each board.

Figure 4-5 shows the structure of the clock synchronization subsystem.

Figure 4-5 Structure of the clock synchronization subsystem



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The structure of the BSC6900 clock synchronization subsystem is described as follows:

l The clock board of the BSC6900 can be the GCUa or GCGa board. The BSC6900 cannotbe configured with both the GCUa and GCGa boards simultaneously. Depending on theclock type, it can have either the GCUa board or the GCGa board.

l If the MPS extracts the clock signals, the clock signals enter the MPS in any of the followingways:– The clock signals enter the port on the panel of the GCUa/GCGa board.

– The clock signals enter the port on the panel of an interface board that can extract lineclock signals. The clock signals are then switched to the GCUa/GCGa board throughthe backplane.

– The GCUa/GCGa board generates oscillator clock signals.

l If the EPS extracts the clock signals, the interface board that extracts clock signals must bethe EIUa/OIUa/PEUa board.

l If the BSC6900 is configured with the Gb interface board, the Gb interface board extractsclock signals either from the backplane or from the CN. The Gb interface board, however,cannot extract clock signals from them simultaneously. If the PS services and CS servicesuse different clock sources and the clock signals are extracted from the CN, the Gb interfaceboard serves only the Gb interface.

Figure 4-6 shows the connections of the clock cables between the clock boards in the MPS andthe SCUa boards in the EPS when the BSC6900 is configured with active and standby clockboards and SCUa boards.

Figure 4-6 Structure of the clock synchronization subsystem

The active and standby clock boards in the MPS are connected to the active and standby SCUaboards in the EPS through the Y-shaped clock signal cables. This connection mode ensures that




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the system clock of the BSC6900 works properly in the case of a single-point failure of the clockboard, Y-shaped clock signal cable, or SCUa board. In addition, the Y-shaped clock signal cableensures the proper working of the SCUa boards during the switchover of the active and standbyclock boards.

NOTE

In the MPS, the clock board sends clock signals to the SCUa board in the same subrack through the backplanechannel. Therefore, a Y-shaped clock signal cable is not required.

4.3.3 Clock Synchronization ProcessThe BSC6900 processes external clock signals before sending them to its boards. The clocksynchronization process varies slightly from one subrack to another.

Process of Clock Synchronization in the MPS/EPSThe clock signals of the MPS/EPS are provided by the clock board. The clock board can extractclock signals from an external device or extract LINE clock signals from the A interface. TheGCGa board can extract clock signals from the GPS.l Figure 4-7 shows the process of clock synchronization in the MPS/EPS when the clock

board extracts clock signals from an external device or from the GPS.l Figure 4-8 shows the process of clock synchronization in the MPS/EPS when the clock

board extracts LINE clock signals from the A interface.

Figure 4-7 Process of clock synchronization in the MPS/EPS (1)



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Figure 4-8 Process of clock synchronization in the MPS/EPS (2)

As shown in Figure 4-7 and Figure 4-8, the process of clock synchronization in the MPS/EPSis as follows:

1. If an external clock is used, external clock signals travel to the clock board through the porton the panel of the clock board. If the GPS clock is used, clock signals travel to the clockboard through the GPS antenna port. If the LINE clock is used, clock signals travel to theclock board through the backplane.

2. The clock source is phase-locked in the clock board to generate clock signals. The clocksignals, then, are sent to the SCUa board in the MPS through the backplane and to the SCUaboard in each EPS through the clock signal output ports.

3. The SCUa board in the MPS/EPS transmits the clock signals to the other boards in the samesubrack through the backplane.

NOTEThe Abis interface boards transmit the clock signals to the base stations.

Process of Clock Synchronization in the TCSFigure 4-9 shows the process of clock synchronization in the TCS when the TCS extracts LINEclock signals from the A interface.

Figure 4-9 Process of clock synchronization in the TCS




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1. The TCS extracts LINE clock signals from the A interface. Then, the LINE clock signalsare processed by the A interface board to obtain the required clock signals.

2. In the TCS, the A interface board transmits the clock signals to the SCUa board throughthe backplane. Then, the SCUa board transmits the clock signals to the other boards in theTCS.

NOTE

l In A over IP over Ethernet mode, the BSC6900 can extract only external clock signals.

l In A over IP over E1/T1 mode, the BSC6900 can extract only LINE clock signals.

4.4 OM PrincipleOM is performed in the following scenarios: routine maintenance, emergency maintenance,troubleshooting, device upgrade, and capacity expansion. In addition, OM can be performed torapidly adjust device status.

4.4.1 Dual OM PlaneThe BSC6900 has a dual OM plane to prevent single-point failure from affecting the normaloperation and maintenance.

4.4.2 OM NetworkThe OM network of the BSC6900 consists of the M2000, LMT, OMU, SCUa boards, and OMmodules in other boards.

4.4.3 Active/Standby WorkspacesThis section describes the active/standby workspaces of the OMU and those of the host boards.

4.4.4 Data Configuration ManagementThe data configuration management involves managing the data configuration process of theBSC6900 so that configuration data is properly sent to the related boards in a secure manner.

4.4.5 Security ManagementThe security management ensures the security of user login and helps to identify equipmentfaults. It involves rights management, log management, and inventory management.

4.4.6 Performance ManagementThe BSC6900 performance management involves collecting, analyzing, and queryingperformance data.

4.4.7 Alarm ManagementThe alarm management helps you monitor the running status of the BSC6900 and informs youof faults in real time so that you can take proper measures in time.

4.4.8 Loading ManagementThe BSC6900 loading management involves managing the process of loading program and datafiles onto boards after the boards (or subracks) are started or restarted.

4.4.9 Upgrade ManagementThe upgrade management involves managing the procedures for upgrading the OMU softwareand patch.

4.4.10 BTS Loading ManagementThe BTS loading management involves managing the process of loading software to the boardsin the BTS.



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4.4.11 BTS Upgrade ManagementThe BTS upgrade management refers to upgrading the BTS to a later version. You can locallyor remotely upgrade multiple BTSs through the OM network.

4.4.1 Dual OM PlaneThe BSC6900 has a dual OM plane to prevent single-point failure from affecting the normaloperation and maintenance.

Figure 4-10 shows this dual OM plane design.

Figure 4-10 Dual OM plane

NOTE

If the internal network and external network are on different network segments, ensure that the two networksare isolated.The physical entity of the OMU can be the OMUa board, OMUb board, or GBAM. Both the OMUa board andthe OMUb board can work in active/standby mode. The following takes the OMUa board as example to describethe dual OM plane.

The dual OM plane design is implemented by the hardware that works in active/standby mode.When an active component is faulty but the standby component works properly, a switchoveris automatically performed between the active and standby components, to ensure that the OMchannel works properly.

The active/standby OMUa boards use the same external virtual IP address to communicate withthe LMT or M2000 and use the same internal virtual IP address to communicate with the SCUaboard.

l When the active OMUa board is faulty, an active/standby switchover is performedautomatically, and the standby OMUa board takes over the OM task. In this case, the




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internal and external virtual IP addresses remain unchanged. Thus, the propercommunication between the internal and external networks of the BSC6900 is ensured.

l When a single-point failure occurs on the switching network, the active/standby SCUaboards in each subrack are switched over automatically to ensure that the OM channelworks properly.

4.4.2 OM NetworkThe OM network of the BSC6900 consists of the M2000, LMT, OMU, SCUa boards, and OMmodules in other boards.

NOTE

The physical entity of the OMU can be the OMUa board, OMUb board, or GBAM. The following takes theOMUa board as example to describe environment monitoring.

Figure 4-11 shows the structure of the BSC6900 OM network.

Figure 4-11 Structure of the OM network

NOTE

Figure 4-11 shows some of the boards in the OM network.

The SCUa boards in the EPS/TCS are connected to the SCUa boards in the MPS through crossover cables. Thecrossover cables transmit OM signals from the MPS to the EPS/TCS.

In remote TCS mode, the SCUa boards in the TCS are connected to the SCUa boards in the MPS through thecables between the Ater interface boards. These cables transmit OM signals from the MPS to the TCS.

M2000

The M2000 is a centralized network management system. The M2000 is connected to theBSC6900 through Ethernet cables. One M2000 can remotely manage multiple BSC6900s.



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LMTThe LMT is connected to the OMUa board of the BSC6900 and works on the Windows XPProfessional or Windows Vista operating system. One or more LMTs can be connected to theOMUa board directly or through networks. The maintenance of the BSC6900 can be performedlocally or remotely through the LMT. The LMT is connected to an alarm box through a serialcable.

OMUa BoardThe OMUa board is the back administration module of the BSC6900. It is connected to anexternal device through the Ethernet cable. The BSC6900 can be configured with one OMUaboard in independent mode or with two OMUa boards in active/standby mode.

The OMUa board functions as a bridge between the BSC6900 and the LMT/M2000. The OMnetwork of the BSC6900 is classified into the following networks:

l Internal network: implements the communication between the OMUa board and the hostboards of the BSC6900.

l External network: implements the communication between the OMUa board and externaldevices, such as the LMT or M2000.

SCUa BoardThe SCUa board is the switching and control board of the BSC6900. It is responsible for theOM of the subrack where it is located. If a subrack is configured with two SCUa boards, thenthe two boards work in active/standby mode.

The SCUa board performs OM on other boards in the same subrack through the backplanechannels. The SCUa boards in different subracks are connected through crossover cables.

4.4.3 Active/Standby WorkspacesThis section describes the active/standby workspaces of the OMU and those of the host boards.

Active/Standby Workspaces of the OMUThe active/standby workspaces of the OMU are used for the upgrade and rollback of theBSC6900 versions, thus enabling quick switching between versions.

Concept of the Active/Standby Workspaces of the OMUThe active/standby workspaces of the OMU refer to the active/standby workspaces for storingthe version files on the OMU. Each workspace is used to store files of different versions.

The relation between the active/standby workspaces is relative. The active/standby relationdepends on the storage location of the running version. The workspace that stores the runningOMU version files is the active workspace, and the other is the standby workspace.

Working Principles of the Active/Standby Workspaces of the OMUThe working principles of the OMU active/standby workspaces in the case of the OMU versionupgrade are as follows:




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1. The standby workspace of the active OMU is upgraded to a new version.2. The standby workspace of the standby OMU is upgraded to a new version.3. A switchover is performed between the active and standby workspaces of the active OMU.

The standby workspace that stores the new version of files becomes active, and the otherworkspace becomes standby.

4. The active OMU runs the upgraded version.5. A switchover is performed between the active and standby workspaces of the standby OMU

to ensure that the versions of the workspaces are consistent with those of the active OMU.6. The OMU version upgrade is complete.

After the OMU version upgrade, the standby workspaces of the active and standby OMUs storethe files of the old version. In this case, version rollback can be performed as required.

The working principles of the OMU active/standby workspaces in the case of version rollbackare as follows:

1. A switchover is performed between the active and standby workspaces of the active OMU.The running version of the active OMU is rolled back to the pre-upgrade version.

2. The active OMU runs the pre-upgrade version.3. A switchover is performed between the active and standby workspaces of the standby OMU

to ensure that the versions of the workspaces are consistent with those of the active OMU.4. The OMU version rollback is complete.

Relation Between Intra-OMU Active and Standby WorkspacesThe active and standby workspaces of the OMU are independent of each other. The operationof the active workspace does not change any information in the standby workspace.

Relation Between Inter-OMU Active and Standby WorkspacesThe active and standby workspaces of the active OMU correspond to the active and standbyworkspaces of the standby OMU respectively. Between the active and standby OMUs, the filesin the active workspaces are automatically synchronized in real time, but those in the standbyworkspaces need to be synchronized manually.

Relation Between the Active/Standby Workspaces of Host Boards and the Active/Standby Workspaces of the OMU

On the active workspaces of the host boards, files can be loaded only from the active workspaceof the OMU. On the standby workspaces of the host boards, files can be loaded only from thestandby workspace of the OMU.

Active/Standby Workspaces of Host BoardsBSC6900 host boards refer to all the boards except the OMUa board. The active/standbyworkspaces of host boards are used for file loading, version upgrade, and version rollback.

Concept of the Active/Standby Workspaces of Host BoardsThe active/standby workspaces of host boards refer to the active/standby workspaces for storingdifferent versions of programs, data, and patch files in the board flash memory.



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The relation between the active/standby workspaces is a relative concept. The active/standbyrelation depends on the running version. The workspace that stores the running version files ofa board is the active workspace, and the other is the standby workspace.

Working Principles of the Active/Standby Workspaces of Host BoardsBefore loading programs and data files, host boards choose the loading mode according to theloading control parameter. For details, see 4.4.8 Loading Management.

Relation Between Intra-Board Active/Standby WorkspacesThe active and standby workspaces of a host board are independent of each other. The operationof the active workspace does not change any information in the standby workspace.

Relation Between Inter-Board Active/Standby WorkspacesThe active and standby workspaces of the active board are independent of the active and standbyworkspaces of another host board. The operation of the active board does not change anyinformation in the standby board.

Relation Between the Active/Standby Workspaces of Host Boards and the Active/Standby Workspaces of the OMU

On the active workspaces of the host boards, files can be loaded only from the active workspaceof the OMU. On the standby workspaces of the host boards, files can be loaded only from thestandby workspace of the OMU.

4.4.4 Data Configuration ManagementThe data configuration management involves managing the data configuration process of theBSC6900 so that configuration data is properly sent to the related boards in a secure manner.

Data Configuration ModesThe BSC6900 supports two data configuration modes: effective mode and ineffective mode.

Effective Mode and ineffective Model Effective mode

If data configuration is performed on the BSC6900 in effective mode, then the relevantconfiguration data takes effect on the host boards in real time.

l Ineffective modeIf data configuration is performed on the BSC6900 in ineffective mode, then the relevantconfiguration data takes effect only after the BSC6900 is reset or is switched to the effectivemode.

Principle of Effective Mode ConfigurationEffective mode configuration is applied to dynamic modification of the BSC6900 configurationdata.

Figure 4-12 shows the principle of effective mode configuration.




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Figure 4-12 Principle of effective mode configuration

The process of effective mode configuration is as follows:

1. The BSC6900 is switched to effective mode.

2. The configuration console (LMT or M2000) sends MML commands to the configurationmanagement module of the OMU.

3. The configuration management module of the OMU sends the configuration data to thedatabase of the related host board and writes the data to the OMU database.

Principle of Ineffective Mode Configuration

Ineffective mode configuration is applied to BSC6900 initial configuration.

Figure 4-13 shows the principle of ineffective mode configuration.

Figure 4-13 Principle of ineffective mode configuration

The process of ineffective mode configuration is as follows:

1. The BSC6900 is switched to ineffective mode.

2. The configuration console (LMT or M2000) sends MML commands to the configurationmanagement module of the OMU.

3. The configuration management module sends only the configuration data to the OMUdatabase.



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4. When a subrack or the BSC6900 is reset, the OMU formats the configuration data in thedatabase into a .dat file, loads the file onto the related host boards, and then activates theconfiguration data.

Data Configuration Rollback

Data configuration rollback is performed to recover configurations when errors occur. If themodified data configuration fails to reach the expected result or even causes equipment ornetwork failure, you can perform rollback to recover the configurations and to ensure the properoperation of the BSC6900.

WARNINGData configuration rollback cannot be performed when the CM control enable switch is set toON, when the fast configuration mode is selected, or when batch configuration is performed.

Data configuration rollback consists of the following types of operation:

l Undoing a single configuration command

After you undo the latest ten commands one by one, the system rolls back to theconfiguration before each command is executed.

l Redoing a single configuration command

After you redo the latest ten commands one by one, the system rolls back to theconfiguration after each command is executed.

l Undoing configuration commands in batches

This operation is performed to undo all the configuration commands that were executedafter a specified rollback savepoint. After this operation, the system rolls back to theconfiguration at the specified rollback savepoint.

l Redoing configuration commands in batches

This operation is performed to redo the configurations that were rolled back in batches.After this operation, the system returns to the configuration at the specified rollbacksavepoint or the configuration after the commands were executed.

Data Configuration Rights Management

The data configuration rights management controls the data configuration rights and the numberof users that simultaneously perform data configuration on the BSC6900 through the LMT orM2000. This ensures the security of data configuration.

The principles of data configuration rights management are as follows:

l The data configuration rights management enables only one user to perform dataconfiguration on the BSC6900 through the LMT or M2000 at a time.

l The user must have data configuration rights.

With the data configuration rights management, users cannot configure data for the BSC6900at the same time.




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Data Configuration Check

The data configuration check involves the data validity check and data consistency check. Thisensures the normal operation of the BSC6900.

Data Validity Check

The data validity check involves checking whether a configuration complies with theconfiguration rules and whether an MML script file complies with the syntactic rules. When aconfiguration is performed or an MML command is executed, the data validity check isperformed. If there is an error in the configuration, the BSC6900 stops the configuration or therunning of the command. At the same time, a warning message is displayed.

Data Consistency Check

The data consistency check consists of two parts:

l Check of the data consistency between the active and standby OMUs

If the BSC6900 is configured with the active and standby OMUs, the data on the activeOMU must be the same as that on the standby OMU, thus ensuring the reliability of theBSC6900. If the active OMU is faulty, the standby OMU takes over the tasks after an active/standby switchover.

l Check of the data consistency between the OMU and the host boards

The data on the host boards must be the same as that on the OMU. Otherwise, the systemcannot run stably. In addition, some data modified by users cannot take effect. Figure4-14 shows the procedure for the data consistency check.

Figure 4-14 Check of the data consistency between the OMU and the host boards

The procedure for checking the data consistency between the OMU and the host boards is asfollows:



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1. On the LMT, a data consistency check command is sent to the OMU automatically on aregular basis or manually.

2. The OMU analyzes the parameters of the command and checks whether the data in theboard databases is the same as that in the OMU database.

3. The OMU generates a result file and sends it to the LMT.

4.4.5 Security ManagementThe security management ensures the security of user login and helps to identify equipmentfaults. It involves rights management, log management, and inventory management.

Rights Management

The rights management is performed to identify a user and define the rights of the user.

The BSC6900 supports multi-user operations. It performs hierarchical rights management forusers to ensure security. The BSC6900 authorizes users at multiple levels and assigns certainrights to the users at each level. To log in to the LMT of the BSC6900, a user must enter theregistered user name and password, through which the BSC6900 identifies the user.

l User types

– Local users: refer to the accounts (including the default local account admin) managedby only the BSC6900 LMT. This type of LMT users can log in to the LMT during theBSC6900 installation and during the disconnection from the M2000.

– Domain users: refer to the accounts that are created, changed, authenticated, andauthorized on the M2000. Domain users can manage the BSC6900 after logging in tothe LMT or after logging in to the M2000 server through the M2000 client.

l User rights

Table 4-1 Definitions of the user rights

Class Rights CommandGroup

Description

Guest Guest can onlybrowse data.

G_0 The objects in this command group are used toquery system information, such as users,command groups, logs, NTP, EMS, and timezones.

G_2 The objects in this command group are used toquery data configurations and consist of theMML commands of the LST type.

G_4 The objects in this command group are used toquery alarm information.

G_6 The objects in this command group are used toquery performance data, for example, a result fileor a task file.




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Description

G_8 The objects in this command group are used toquery device information such as device statusand consist of the MML commands of the DSPtype.

G_13 The objects in this command group are used toquery the information about base stations, forexample, the attributes and boards of basestations.

User In addition tothe rightsgranted to theGuest, Usercan performsystem OM.

G_7 The objects in this command group are used toperform performance management, for example,to activate a performance task file or to upload aperformance result file.

G_9 The objects in this command group are used toperform device management, for example, toreset, block, unblock, or switch over a board.

G_10 The objects in this command group are used totrace and monitor the signal flow on the controlplane and on the user plane, for example, to querya tracing task or to create/delete/start a tracingtask.

G_11 The objects in this command group are used tomodify device panels.

G_12 The objects in this command group are used toperform software management, for example,patch management.

G_14 The objects in this command group are used toperform base station management, for example,to manage base station software or to reset a basestation.

Operator In addition tothe rightsgranted to theUser, theOperator canperform dataconfigurationon theequipment.

G_3 The objects in this command group are used toconfigure data, for example, the data for a newcell.

G_5 The objects in this command group are used toperform alarm management, for example, toclear an alarm or to set the alarm level.



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Description

Administrator

Administratorhas the highestoperationrights. It canmanage all theother users.

G_1 The objects in this command group are used tomanage system information, for example, tomanage a user, to set the time zone, to set thedaylight saving time, or to perform batchconfiguration.

Custom The rights of this user are defined by the Administrator.

Log Management

Log management records the operation history and saves the related logs about the BSC6900.Thus, it helps analyze and identify faults.

Table 4-2 lists the types of logs that are recorded when the BSC6900 is running.

Table 4-2 Types of logs

Type Description

Running log Records the information on the operating status of the system. Theinformation is used to analyze and locate faults.

Operation log Records the information on operation and maintenance performedby users.

Security log Records the information on the operations that may affect the systemsecurity, for example, the information on the change of userpassword.

The log management provides the following functions:

l Saving log files

You can save the log information to the OMU by setting the log record parameters.

l Uploading log files

You can upload the log files in the OMU to a specified FTP server by setting the uploadingparameters.

l Querying log files

You can view the specified log information in the OMU by setting the querying conditions.

l Extracting the up-to-date logs from the buffer

You can obtain the latest log information by saving the logs stored in the buffer to the logfile.




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NOTE

The OMU saves the log information in the buffer. When the log information reaches the specified limitor the current time reaches the log record period, the OMU records the log file.

Inventory ManagementThe inventory management refers to the efficient and centralized management of the primaryconfiguration information about the equipment in the network.

By exporting and uploading the inventory information files on the M2000, you can learn thephysical and logical configurations of NEs. The inventory management system is deployed onthe M2000. It obtains the required inventory information from NEs through the related interfaces.NEs report inventory information to the M2000 in the form of files, which contain theinformation on the following aspects:

l Equipment

l Connection

l Modules

l Configurations

l Peer equipment

l Host version

l Cabinets

l Subracks

l Boards and the Flash electronic labels of the boards

l Slots

l Ports

l Antennas

4.4.6 Performance ManagementThe BSC6900 performance management involves collecting, analyzing, and queryingperformance data.

Performance Management ProcessThe boards of the BSC6900 collect performance measurement data and periodically report thedata to the performance measurement module of the OMU. According to the task file, theperformance measurement module reports the measurement data to the M2000 periodically. TheOMU stores a maximum of 25 GB performance measurement data generated within the last 14days. If the data exceeds the time or size, the data on the earliest day is deleted.

Figure 4-15 shows the process of collecting performance measurement data periodically by theBSC6900.



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Figure 4-15 Process of collecting performance measurement data periodically

The process of collecting performance measurement data periodically is as follows:

1. The user registers a performance measurement task and specifies the object, time, and itemattributes of the task on the M2000 client.

2. Based on the performance measurement task, the M2000 server modifies the measurementtask file, sends it to the OMU, and issues a command to activate the modified measurementtask file.

3. Based on the modified measurement task file, the OMU requests host boards to collect dataaccording to the new requirements. The OMU receives the measurement results from thehost boards and saves them as files.

4. The OMU notifies the M2000 server of the measurement results and uploads the files intothe M2000 server. The M2000 server processes the files and saves them into the database.

5. Based on the performance measurement task registered by the M2000 client, the M2000server obtains the relevant results from the database, performs certain calculation on them,and then sends the result to the M2000 client.

Measurement Types

Performance measurement objects are of three types: default measurement objects, optionalmeasurement objects, and real-time measurement objects.

l Default measurement objectsThe BSC6900 automatically measures all objects of this type. The default measurementtask file supports three periods:– Normal measurement period with a default duration of 30 minutes or 60 minutes. A

proper measurement period can be selected on the M2000.– Short measurement period with a default duration of 5 minutes or 15 minutes. A proper

measurement period can be selected on the M2000.– Long measurement period with a default duration of 24 hours.

You cannot add objects to or remove objects from the list of default measurement objectson the M2000.

l Optional measurement objectsBy default, the BSC6900 does not measure the optional measurement objects. The purposeof defining optional measurement objects is to avoid measuring these objects every timebecause they are of a large quantity. You can add objects to or remove objects from the listof optional measurement objects on the M2000.




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l Real-time measurement objectsThe BSC6900 measures real-time measurement objects in a short measurement period ofone minute. The purpose is to monitor the changes in target KPIs in real time. The M2000can start or stop real-time measurement tasks. Real-time measurement data is reported tothe M2000 through messages.

4.4.7 Alarm ManagementThe alarm management helps you monitor the running status of the BSC6900 and informs youof faults in real time so that you can take proper measures in time.

Alarm Management Functionl Setting the storage capacity and time limit for alarm logs

The BSC6900 can store the information of the alarms generated in the latest 90 days anda maximum of 100,000 alarm logs. You can set the storage capacity and time limit asrequired.

l Alarm shieldingYou can shield an alarm by alarm ID. Alternatively, you can shield a specific alarm or allalarms of a BTS, cell, board, port, or DSP by setting alarm shielding conditions, thusreducing the number of reported derivative alarms.

l Alarm alertWhen a fault alarm occurs, the BSC6900 can notify you by Email, icon flash, short message,terminal sound, and audible and visual indication of alarm box.

l Alarm information processingYou can browse alarm information in real time, query history alarm information, and handlealarms based on the handling suggestions available on the online help.

Alarm Management ProcessThe alarm management process consists of alarm generation, alarm reporting, alarm handling,and alarm clearance. Figure 4-16 shows the process of alarm management.

Figure 4-16 Alarm management process

Each board detects alarms and reports them to the OMU automatically. The OMU then classifiesthese alarms into different severity levels and sends them to the LMT or the M2000 server. Youcan view and manage alarm information on the LMT or M2000 client.



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The alarm management module of the OMU provides the following functions:

l Alarm storage

The alarm management module stores the alarms in the database of the OMU.

l Alarm processing

The alarm management module processes the operation commands from the LMT orM2000 client and then returns the operation results to the LMT or M2000 client. Thesecommands include querying active alarms, querying alarm logs, and modifying alarmconfiguration items.

l Alarm triggering

If the generation of an alarm triggers another alarm, the alarm management module reportsthe two alarms to the LMT or M2000 client.

l Alarm recovery

After an alarm is handled, the system automatically clears the alarm. At the same time, thealarm management module clears the alarm information from the LMT or M2000.

Alarm Box

The alarm box generates audible and visual alarms. The red, orange, yellow, and green alarmindicators on the alarm box indicate the critical, major, minor, and warning alarms respectively.Different alarm severity levels have different alarm sounds. Figure 4-17 shows the workingprinciple of the alarm box.

Figure 4-17 Working principle of the alarm box

The alarm box is connected to the LMT through a serial cable. When an alarm is reported, theLMT forwards it to the alarm box. The alarm box then generates an audible and visual alarm.You can stop alarm sounds, turn off alarm indicators, and reset the alarm box through the LMT.

4.4.8 Loading ManagementThe BSC6900 loading management involves managing the process of loading program and datafiles onto boards after the boards (or subracks) are started or restarted.

NOTE


Principle of Loading

The OMUa board and the active SCUa board in each subrack play important roles during theBSC6900 loading process.




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l The OMUa board functions as the first-level center of the entire BSC6900 loadingmanagement process. The loading and power-on of the OMUa board are independent ofother boards. The OMUa board processes the loading control requests of other boards.

l The active SCUa board functions as the second-level center of the loading managementprocess. If the OMUa board is not in position, the active SCUa board in a subrack processesthe loading control requests from the other boards in the same subrack. If the SCUa boardsin an extension subrack are not started, the active SCUa board in the main subrack processesthe loading control requests from the boards in the extension subrack.

l The SCUa board in the main TCS functions as the file transfer server during the TCS loadingprocess. If a board in a TCS needs to load files from the OMUa board, the SCUa board inthe main TCS downloads the files from the OMUa board and then processes the filedownload request from the board.

Loading ProcessThe BSC6900 loading process varies according to the configuration mode of subracks and thelocation of TCS.

l Scenario 1: BM/TC separated and local TCSFigure 4-18 shows the loading process.

Figure 4-18 Loading process (1)

– If the OMUa board is in effective mode, the loading process is as follows:

1. After a board is started, it sends a BOOTP request.2. After receiving the BOOTP request message from the board, the OMUa board

generates a BOOTP response message and sends it to the board. The response



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message contains the loading control parameter, IP address, and versioninformation.

3. After receiving the response message, the board loads the program files and datafiles according to the loading control parameter.

4. The loading is complete.– If the OMUa board is not started or is in ineffective mode, the loading process is as

follows:1. After a board is started, the board sends a BOOTP request.2. If the board does not receive any response 30 seconds after the request is sent, the

SCUa board loads the program files and data files from its flash memory.3. After the SCUa board in the MPS loads the program files and data files, it processes

the BOOTP requests from the other boards in the MPS and from the SCUa boardsin the EPS and TCS.

4. After the SCUa board in the EPS or TCS loads the program files and data files, itprocesses the BOOTP requests from the other boards in the same subrack.

5. After receiving the response messages, the other boards in each subrack loadprogram files and data files from their flash memories.

6. The loading is complete.l Scenario 2: BM/TC separated and remote TCS

In this scenario, the Ater interface functions as the loading path between the BM and theTC. Figure 4-19 shows the loading process.





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1. After a board is started, the board sends a BOOTP request.2. After receiving the BOOTP request message from the board, the OMUa board

generates a BOOTP response message and sends it to the board. The responsemessage contains the loading control parameter, IP address, and versioninformation.

3. After receiving the BOOTP response message, the board in the MPS or EPS loadsthe program files and data files according to the loading control parameter.

4. After the Ater interface board in the MPS loads the program files and data files, itfunctions as the loading proxy of the Ater interface board in the main TCS andforwards the BOOTP request and response messages.

5. After the Ater interface board in the main TCS loads the program files and datafiles, it functions as the loading proxy of the other boards in the TCS and forwardsthe BOOTP request and response messages.

6. After receiving the response messages, the other boards in the TCS load programfiles and data files according to the loading control parameter.


follows:

1. After a board is started, the board sends a BOOTP request.2. If the board does not receive any response 30 seconds after the request is sent, the


the BOOTP requests from the other boards in the MPS and from the SCUa boardin the EPS.

4. After the SCUa board in the EPS loads the program files and data files, it processesthe BOOTP requests from the other boards in the same subrack.

5. After receiving the response messages, the other boards in the EPS load programfiles and data files according to the loading control parameter.

6. After the Ater interface board in the MPS loads the program files and data files, itfunctions as the loading proxy of the Ater interface board in the main TCS andforwards the BOOTP request and response messages.

7. After the Ater interface board in the main TCS loads the program files and datafiles, it functions as the loading proxy of the other boards in the TCS and forwardsthe BOOTP request and response messages.

8. After receiving the response messages, the other boards in the TCS load programfiles and data files from their flash memories.

9. The loading is complete.l Scenario 3: BM/TC combined or A over IP

Figure 4-20 shows the loading process.



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1. After a board is started, it broadcasts a BOOTP request.2. After receiving the BOOTP request message from the board, the OMUa board

generates a BOOTP response message and sends it to the board. The responsemessage contains the loading control parameter, IP address, and versioninformation.

3. After receiving the response message, the board loads the program files and datafiles according to the loading control parameter.


follows:

1. After a board is started, the board sends a BOOTP request.2. If the board does not receive any response 30 seconds after the request is sent, the


the BOOTP requests from the other boards in the MPS and from the SCUa boardin the EPS.

4. After the SCUa board in the EPS loads the program files and data files, it processesthe BOOTP requests from the other boards in the same subrack.

5. After receiving the response messages, the other boards in the MPS/EPS loadprogram files and data files from their flash memories.

6. The loading is complete.

4.4.9 Upgrade ManagementThe upgrade management involves managing the procedures for upgrading the OMU softwareand patch.




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Upgrade Scenarios

The BSC6900 needs to be upgraded to rectify the existing defects and to support new functions,higher specifications, and later protocol standards. The upgraded version can provide better QoS.

Upgrade Mode

You can use the dedicated upgrade tool to upgrade the BSC6900 through the OM network ofthe BSC6900. See Figure 4-21.

Figure 4-21 Upgrade through the OM network

NOTE

The upgrade tool supports the upgrade of multiple BSC6900s in batches.

Upgrade Process

The BSC6900 is upgraded remotely by using the dedicated upgrade tool, which consists of theupgrade client and the upgrade server. Figure 4-22 shows the upgrade process.

Figure 4-22 Upgrade process



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NOTE

Client PC refers to the PC on which the upgrade client software runs.

1. The user sends the upgrade version files and the upgrade server program to the specifieddirectories of the active OMU through the network.

2. The user connects the client PC to the active OMU and then starts the upgrade client onthe client PC and the upgrade server on the active OMU to set up the connection betweenthe upgrade client and the upgrade server.

3. The upgrade server synchronizes the version files of the standby OMU with those of theactive OMU.

4. The user starts the upgrade server on the standby OMU and sets up the connection betweenthe upgrade server on the standby OMU and the upgrade server on the active OMU.

5. The upgrade server on the active OMU performs health check on the data and files in theactive workspace of the active OMU and then backs them up before the upgrade.

6. The upgrade server of the active OMU upgrades the software in the standby workspace ofthe active OMU. At the same time, the upgrade server of the standby OMU upgrades thesoftware in the standby workspace of the standby OMU.

7. The upgrade server of the active OMU upgrades the data in the standby workspace of theactive OMU.

8. The upgrade server of the active OMU issues a command to load the host program, DSP,BOOTROM, and data files in the standby workspace of the active OMU onto the standbyworkspaces of the host boards so that the standby workspaces of the boards aresynchronized with the standby workspace of the active OMU.

9. The upgrade server of the active OMU issues a command to switch over the active andstandby workspaces of the active OMU to upgrade the active OMU.

10. The upgrade server of the active OMU issues a command to reset all the standby boards ofthe BSC6900.

11. After the reset, all the standby boards of the BSC6900 automatically load the program filesand data files from the standby workspaces of their flash memories to upgrade the boards.

12. After the upgrade server of the active OMU detects that all the standby boards are started,it issues a command to reset all the active boards of the BSC6900.

13. When the active boards are being reset, the original standby boards become active.Similarly, after the reset, all the original active boards automatically load the program filesand data files from the standby workspaces of their flash memories to upgrade themselves.

14. After the service verification is successful, the upgrade server of the active OMU issues acommand to switch over the active and standby workspaces of the standby OMU so as toupgrade the standby OMU. After the switchover, the standby OMU automaticallysynchronizes with the active OMU.

The upgrade is complete.

4.4.10 BTS Loading ManagementThe BTS loading management involves managing the process of loading software to the boardsin the BTS.

l For the BTS connected to an IP Abis interface board, the loading management process isas follows:




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1. After the BTS is started, it attempts to establish the OML and then broadcasts a DHCPrequest over the OML.

2. After receiving the DHCP request, the SCUa board in the subrack, in which the Abisinterface board connected to the BTS is located, processes the request and sends aDHCP response to the BTS. Through this response, the SCUa board notifies the BTSof the IP address of the BTS board and the IP address of the OMUa board.

3. Based on the version number of the BTS, the BSC6900 reads the version configurationfile from the corresponding BTS version directory on the hard disk of the OMUa board,obtains the information about the software version numbers of all the BTS boards,and then sends the information to the BTS.

4. After obtaining the software version numbers, the BTS automatically checks whetherthe number of the version running on each board is the same as the obtained number.If there is any inconsistency, the BTS requests the BSC6900 to load and activate theversion software.

5. After running the version software, the BTS requests the BSC6900 for configurationdata.

6. The OMUa board obtains the BTS configuration data from its database and sends itto the BTS through messages. Then, the BTS is initialized.

l For the BTS connected to a non-IP Abis interface board, the loading management processis as follows:

1. After the BTS is started, it attempts to establish the OML.2. The BSC6900 sends a version check request to the BTS. Then, the BTS reports its

version information to the BSC6900.3. The BSC6900 checks the BTS version number. If the BTS version does not match the

BSC6900 version, the BSC6900 sends a version loading request to the BTS,instructing the BTS boards to obtain and load program files from the OMUa board.

4. After receiving a loading completion indication message from the BTS, theBSC6900 sends a version activation request to the BTS, instructing the BTS boardsto run the new version.

5. After running the version software, the BTS requests the BSC6900 for configurationdata.

6. The OMUa board obtains the BTS configuration data from its database and sends itto the BTS through messages. Then, the BTS is initialized.

4.4.11 BTS Upgrade ManagementThe BTS upgrade management refers to upgrading the BTS to a later version. You can locallyor remotely upgrade multiple BTSs through the OM network.

NOTE


The BTS upgrade process is as follows:

1. Downloading BTS software

(1) The LMT or M2000 sends a download request to the OMUa board.(2) The OMUa board responds to the request. The LMT or M2000 downloads the BTS

software to the specified directory on the OMUa board through FTP.



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2. Loading BTS software

(1) The LMT or M2000 sends a loading command to the OMUa board. The OMUa boardthen sends the loading command to the BTS.

(2) The BTS responds to the command. The OMUa board and the SCUa board performthe BTS loading management and load the software from the OMUa board to theBTS.

3. Activating BTS software

(1) The LMT or M2000 sends an activation command to the OMUa board.(2) The OMUa board checks the activation command and then forwards it to the BTS.(3) The BTS activates the software. Then, the BTS is reset.

4. Verifying upgrade result

You should verify services to ensure that the BTS is successfully upgraded.




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5 Signal Flow

About This Chapter

The BSC6900 signal flow consists of the user-plane signal flow, control-plane signal flow, andOM signal flow.

Definitionsl User plane

User plane refers to the set of logical functions of the BSC6900 that process the servicedata, including the speech data and packet data.

l Control planeControl plane refers to the set of logical functions of the BSC6900 that process the controlsignaling, including the call control signaling and the connection control signaling.

5.1 User-Plane Signal FlowThe user plane of the BSC6900 processes the user-plane messages on each interface.

5.2 Control-Plane Signal FlowThe control plane of the BSC6900 processes the control-plane messages on each interface.

5.3 OM Signal FlowOM signal flow refers to the messages transmitted between the BSC6900 and the LMT/M2000.The LMT or M2000 maintains and monitors the BSC6900 in real time through the OM signalflow.

BSC6900 GSMTechnical Description 5 Signal Flow


5-1

5.1 User-Plane Signal FlowThe user plane of the BSC6900 processes the user-plane messages on each interface.

5.1.1 CBC Signal FlowThe data from the CBC-BSC interface to the Abis interface refers to the Cell Broadcast Center(CBC) signal flow.

5.1.2 GSM CS Signal FlowAfter a CS call is established in the GSM network, the MS and the network communicate witheach other through the CS signal flow. The method of processing the GSM CS signal flow variesaccording to the transmission mode adopted on the Abis and A interfaces and the configurationmode of the BSC6900 subracks.

5.1.3 GSM PS Signal FlowAfter a PS connection is established in the GSM network, the MS and the network communicatewith each other through the PS signal flow. The GSM PS signal flow varies according to thetransmission mode adopted on the Abis interface.

5.1.1 CBC Signal FlowThe data from the CBC-BSC interface to the Abis interface refers to the Cell Broadcast Center(CBC) signal flow.

Figure 5-1 shows the signal flow from the CBC-BSC interface to the Abis interface.

Figure 5-1 Signal flow from CBC-BSC to Abis

NOTE

l The INT in the figure stands for the interface board. You can use different interface boards as required.

l The boards shown in Figure 5-1 are only examples.

The signal flow is as follows:

1. The CBC sends the broadcast data to the XPUa board of the BSC6900 over the CBC-BSCinterface. The XPUa board processes the data according to the related protocols and thensends it to the Abis interface board.

5 Signal FlowBSC6900 GSM



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NOTE

If the XPUa board in a subrack cannot process the data, the data is switched by the MPS to the XPUaboard in another subrack.

2. The Abis interface board processes the data and then sends it to the BTS.3. The BTS broadcasts the data to the MSs in the cells served by the base station.

5.1.2 GSM CS Signal FlowAfter a CS call is established in the GSM network, the MS and the network communicate witheach other through the CS signal flow. The method of processing the GSM CS signal flow variesaccording to the transmission mode adopted on the Abis and A interfaces and the configurationmode of the BSC6900 subracks.

Abis over TDM and A over TDMFigure 5-2 shows the CS signal flow in Abis over TDM, Ater over TDM, A over TDM, andBM/TC separated mode.

NOTE

l The Abis, Ater, and A interface boards can be the EIUa/OIUa/POUc board. The boards shown in Figure5-2, Figure 5-3, and Figure 5-4 are only examples.


Figure 5-2 GSM CS signal flow (1)

As shown in Figure 5-2, the CS signal flow on the uplink is as follows:

1. The uplink CS signals are sent from the BTS to the Abis interface board in the MPS/EPS.2. The CS signals are demultiplexed in the Abis interface board. Each CS signal uses a 64

kbit/s timeslot and is transmitted to the Ater interface board through the TNUa board.3. The CS signals are multiplexed in the Ater interface board. Each full-rate CS signal uses a

16 kbit/s sub-timeslot, and each half-rate CS signal uses an 8 kbit/s sub-timeslot. The CSsignals are then transmitted to the Ater interface board in the TCS over the Ater interface.

4. The CS signals are demultiplexed in the Ater interface board of the TCS. Each CS signaluses a 64 kbit/s timeslot and is transmitted to the DPUc board through the TNUa board.

5. The DPUc board performs speech codec and rate adaptation on the CS signals, which areconverted into 64 kbit/s PCM signals. The 64 kbit/s PCM signals are transmitted to the Ainterface board through the TNUa board and then to the MSC over the A interface.



5-3

The downlink flow is the reverse of the uplink flow.

Figure 5-3 shows the CS signal flow in Abis over TDM, Ater over IP, A over TDM, and BM/TC separated mode.




kbit/s timeslot and is transmitted to the Ater interface board through the TNUa board, DPUcboard, and SCUa board in sequence.

3. The CS signals are multiplexed in the Ater interface board. Each full-rate CS signal uses a16 kbit/s sub-timeslot, and each half-rate CS signal uses an 8 kbit/s sub-timeslot. The CSsignals are then transmitted to the Ater interface board in the TCS over the Ater interface.




In the case of BM/TC combined mode, the Ater interface does not exist. Figure 5-4 shows theCS signal flow in Abis over TDM and A over TDM mode.





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kbit/s timeslot and is transmitted to the DPUc board through the TNUa board.3. The DPUc board performs speech codec and rate adaptation on the CS signals, which are

converted into 64 kbit/s PCM signals. The 64 kbit/s PCM signals are transmitted to the Ainterface board through the TNUa board and then to the MSC over the A interface.


Abis over IP and A over TDMFigure 5-5 shows the CS signal flow in Abis over IP, Ater over TDM, A over TDM, and BM/TC separated mode.

NOTE

l The Abis interface board can be the PEUa/FG2a/GOUa/POUc/FG2c/GOUc board, and the Ater and Ainterface boards can be the EIUa/OIUa/POUc board. The boards shown in Figure 5-5, Figure 5-6, andFigure 5-7 are only examples.




1. The uplink CS signals are sent from the BTS to the Abis interface board in the MPS/EPS.2. The CS signals are transmitted from the Abis interface board to the DPUc board through

the SCUa board.3. The DPUc board reorders PTRAU frames, eliminates jitter, and converts PTRAU frames

into TRAU frames. Then, the TRAU frames are transmitted to the Ater interface boardthrough the TNUa board.

4. The CS signals are multiplexed in the Ater interface board in the MPS/EPS, and then aretransmitted to the Ater interface board in the TCS.





5-5


Figure 5-6 shows the CS signal flow in Abis over IP, Ater over IP, A over TDM, and BM/TCseparated mode.




kbit/s timeslot and is transmitted to the Ater interface board through the SCUa board.3. The CS signals are multiplexed in the Ater interface board. Each full-rate CS signal uses a

16 kbit/s sub-timeslot, and each half-rate CS signal uses an 8 kbit/s sub-timeslot. The CSsignals are then transmitted to the Ater interface board in the TCS over the Ater interface.




In the case of BM/TC combined mode, the Ater interface does not exist. Figure 5-7 shows theCS signal flow in Abis over IP and A over TDM mode.





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1. The uplink CS signals are sent from the BTS to the Abis interface board in the MPS/EPS.2. The CS signals are transmitted to the DPUc board through the SCUa board.3. The DPUc board reorders PTRAU frames, eliminates jitter, and performs speech codec and

rate adaptation on the PTRAU frames, which are converted into 64 kbit/s PCM frames.4. The PCM frames are transmitted to the A interface board through the TNUa board, and

then are transmitted to the MSC over the A interface.


Abis over TDM and A over IPIn the case of A over IP, the Ater interface does not exist. Figure 5-8 shows the CS signal flowin Abis over TDM and A over IP transmission mode.

NOTE

l The Abis interface board can be the EIUa/OIUa/POUc board, and the A interface board can be the FG2a/GOUa/FG2c/GOUc/POUc board. The boards shown in Figure 5-8 are only examples.





kbit/s timeslot and is transmitted to the DPUc board through the TNUa board.3. The DPUc board converts PTRAU frames into RTP frames, reorders RTP frames, and

eliminates jitter.4. The SCUa board transmits the CS signals to the A interface board, which then transmits

the signals to the MGW over the A interface.


Abis over IP and A over IPIn the case of A over IP, the Ater interface does not exist. Figure 5-9 shows the CS signal flowin Abis over IP and A over IP transmission mode.



5-7

NOTE

l The Abis interface board can be the PEUa/FG2a/GOUa/POUc/FG2c/GOUc board, and the A interface boardcan be the FG2a/GOUa/PEUa/FG2c/GOUc/POUc board. The boards shown in Figure 5-9 are onlyexamples.




1. The uplink CS signals are sent from the BTS to the Abis interface board in the MPS/EPS.2. The Abis interface board encapsulates the CS signals in PTRAU frames, which are then

transmitted to the DPUc board through the SCUa board.3. The DPUc board converts PTRAU frames into RTP frames, reorders RTP frames, and

eliminates jitter.4. The SCUa board transmits the CS signals to the A interface board, and then the A interface

board transmits the signals to the MGW over the A interface.


5.1.3 GSM PS Signal FlowAfter a PS connection is established in the GSM network, the MS and the network communicatewith each other through the PS signal flow. The GSM PS signal flow varies according to thetransmission mode adopted on the Abis interface.

Abis over TDMFigure 5-10 shows the PS signal flow in Abis over TDM transmission mode.

NOTE

l The Abis interface board can be the EIUa/OIUa/POUc board, and the Gb interface board can be the PEUa/FG2a/POUc/FG2c/GOUc board. The boards shown in Figure 5-10 are only examples.





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Figure 5-10 GSM PS signal flow (1)

As shown in Figure 5-10, the PS signal flow on the uplink is as follows:

1. The packet data is sent from the BTS to the Abis interface board in the MPS/EPS. The datauses one to four 16 kbit/s sub-timeslots on the Abis interface, depending on the modulationand coding scheme, for example, CS1-CS4 or MCS1-MCS9.

2. The Abis interface board transmits the packet data to the TNUa board, which then transmitsthe data to the DPUd board.

3. The DPUd board converts the frame format and then transmits the data to the Gb interfaceboard through the SCUa board.

4. The Gb interface board processes the packet data according to the IP or FR protocol andthen transmits it to the SGSN over the Gb interface.


Abis over IPFigure 5-11 shows the PS signal flow in Abis over IP transmission mode.

NOTE

l The Abis interface board can be the PEUa/FG2a/GOUa/POUc/FG2c/GOUc board, and the Gb interfaceboard can be the PEUa/FG2a/POUc/FG2c/GOUc board. The boards shown in Figure 5-11 are onlyexamples.


Figure 5-11 GSM PS signal flow (2)



5-9

As shown in Figure 5-11, the PS signal flow on the uplink is as follows:

1. The packet data is sent from the BTS to the Abis interface board in the MPS/EPS.

2. The SCUa board transmits the packet data to the DPUd board.

3. The DPUd board converts the frame format and then transmits the data to the Gb interfaceboard through the SCUa board.

4. The Gb interface board processes the packet data according to the IP or FR protocol andthen transmits it to the SGSN over the Gb interface.


5.2 Control-Plane Signal FlowThe control plane of the BSC6900 processes the control-plane messages on each interface.

5.2.1 Signaling Flow on the A InterfaceThe signaling flow on the A interface refers to the signaling messages transmitted between theBSC6900 and the MGW/MSC. The signaling flow varies according to the transmission modeadopted on the A interface.

5.2.2 Signaling Flow on the Abis InterfaceThe signaling flow on the Abis interface refers to the signaling messages transmitted betweenthe BSC6900 and the base station. The signaling flow varies according to the transmission modeadopted on the Abis interface.

5.2.3 Signaling Flow on the Gb InterfaceThe signaling flow on the Gb interface refers to the signaling messages transmitted between theBSC6900 and the SGSN.

5.2.4 Signaling Flow on the Pb InterfaceThe signaling flow on the Pb interface refers to the signaling messages transmitted between theBSC6900 and the external PCU.

5.2.1 Signaling Flow on the A InterfaceThe signaling flow on the A interface refers to the signaling messages transmitted between theBSC6900 and the MGW/MSC. The signaling flow varies according to the transmission modeadopted on the A interface.

A over TDM

In A over TDM mode, the signaling flow on the A interface varies according to the configurationmode of BSC6900 subracks.

l Figure 5-12 shows the signaling flow on the A interface in BM/TC separated mode.

l Figure 5-13 shows the signaling flow on the A interface in BM/TC combined mode.

NOTE

l The A interface board can be the EIUa/OIUa/POUc board, and the XPUa/XPUb board processes signaling.The boards shown in Figure 5-12 and Figure 5-13 are only examples.





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Figure 5-12 Signaling flow on the A interface in A over TDM mode (BM/TC separated)

As shown in Figure 5-12, the uplink signaling flow on the A interface is as follows:

1. In the MPS/EPS, the XPUa board processes the signaling according to the MTP3, SCCP,and BSSAP protocols. Then, the signaling is transmitted to the Ater interface board throughthe SCUa board.

2. The Ater interface board processes the signaling according to the MTP2 protocol. Then,the signaling is transmitted to the Ater interface board in the TCS.

3. In the TCS, the Ater interface board transparently transmits the signaling to the TNUa boardand then to the A interface board. Then, the signaling is transmitted to the MSC over theA interface.


Figure 5-13 Signaling flow on the A interface in A over TDM mode (BM/TC combined)


1. In the MPS/EPS, the XPUa board processes the signaling according to the MTP3, SCCP,and BSSAP protocols. Then, the signaling is transmitted to the A interface board throughthe SCUa board.

2. The A interface board processes the signaling according to the MTP2 protocol. Then, thesignaling is transmitted to the MSC over the A interface.


A over IPFigure 5-14 shows the signaling flow on the A interface in A over IP mode.



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NOTE

l The A interface board can be the FG2a/GOUa/FG2c/GOUc/POUc board, and the XPUa/XPUb boardprocesses signaling. The boards shown in Figure 5-14 are only examples.


Figure 5-14 Signaling flow on the A interface in A over IP mode


1. In the MPS/EPS, the XPUa board processes the signaling according to the BSSAP, SCCP,SCTP, and M3UA protocols. Then, the signaling is transmitted to the A interface boardthrough the SCUa board.

2. The A interface board processes the signaling according to the IP protocol. Then, thesignaling is transmitted to the MSC server through the MGW.


5.2.2 Signaling Flow on the Abis InterfaceThe signaling flow on the Abis interface refers to the signaling messages transmitted betweenthe BSC6900 and the base station. The signaling flow varies according to the transmission modeadopted on the Abis interface.

Abis over TDMFigure 5-16 shows the signaling flow on the Abis interface in Abis over TDM mode.

NOTE

l The Abis interface board can be the EIUa/OIUa/POUc board, and the XPUa/XPUb board performs signalingprocessing. The boards shown in Figure 5-15 are only examples.





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Figure 5-15 Signaling flow on the Abis interface in Abis over TDM mode

As shown in Figure 5-15, the uplink signaling flow on the Abis interface is as follows:

1. The signaling from the BTS is transmitted to the Abis interface board in the MPS/EPS overthe Abis interface and is then transmitted to the SCUa board.

2. The SCUa board transmits the signaling to the signaling processing board.


Abis over IPFigure 5-16 shows the signaling flow on the Abis interface in Abis over IP mode.

NOTE

l The Abis interface board can be the FG2a/GOUa/PEUa/FG2c/GOUc/POUc board, and the XPUa/XPUbboard performs signaling processing. The boards shown in Figure 5-16 are only examples.


Figure 5-16 Signaling flow on the Abis interface in Abis over IP mode

As shown in Figure 5-16, the uplink signaling flow on the Abis interface is as follows:

1. The signaling from the BTS is transmitted to the Abis interface board in the MPS/EPS overthe Abis interface.

2. The Abis interface board processes the signaling according to the MAC, IP, and UDPprotocols. Then, the signaling is transmitted to the signaling processing board through theSCUa board.




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5.2.3 Signaling Flow on the Gb InterfaceThe signaling flow on the Gb interface refers to the signaling messages transmitted between theBSC6900 and the SGSN.

Figure 5-17 shows the signaling flow on the Gb interface.

NOTE

l The Gb interface board can be the PEUa/FG2a/POUc/FG2c board, and the XPUa/XPUb board performssignaling processing. The boards shown in Figure 5-17 are only examples.


Figure 5-17 Signaling flow on the Gb interface

As shown in Figure 5-17, the uplink signaling flow on the Gb interface is as follows:

1. In the MPS/EPS, the signaling processing board processes the signaling according to theNS and BSSGP protocols. Then, the signaling is transmitted to the Gb interface boardthrough the SCUa board.

2. The Gb interface board processes the signaling according to the IP or FR protocol. Then,the signaling is transmitted to the SGSN over the Gb interface.


5.2.4 Signaling Flow on the Pb InterfaceThe signaling flow on the Pb interface refers to the signaling messages transmitted between theBSC6900 and the external PCU.

Figure 5-18 shows the signaling flow on the Pb interface.

NOTE

l The Pb interface board can be the EIUa/OIUa/POUc board, and the XPUa board performs signalingprocessing. The boards shown in Figure 5-18 are only examples.





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Figure 5-18 Signaling flow on the Pb interface

As shown in Figure 5-18, the uplink signaling flow on the Pb interface is as follows:

1. In the MPS/EPS, the signaling processing board processes the signaling according to theIP and RR protocols. Then, the signaling is transmitted to the Pb interface board throughthe SCUa board.

2. The Pb interface board processes the signaling according to the LAPD protocol. Then, thesignaling is transmitted to the PCU over the Pb interface.


5.3 OM Signal FlowOM signal flow refers to the messages transmitted between the BSC6900 and the LMT/M2000.The LMT or M2000 maintains and monitors the BSC6900 in real time through the OM signalflow.

NOTE


The OM signal flow varies according to the configuration mode of subracks.

Scenario 1: BM/TC SeparatedFigure 5-19 shows the OM signal flow in the BSC6900 in BM/TC separated mode.



5-15

Figure 5-19 OM signal flow (BM/TC separated)

As shown in Figure 5-19, the OM signal flow in the BSC6900 is as follows:

l OM signal flow in the MPS

1. The OM signal is transmitted from the LMT or M2000 to the OMUa board in theMPS.

2. After the OM signal is processed by the OMUa board, it is transmitted to the SCUaboard through the backplane of the MPS.

3. The SCUa board then transmits the OM signal to the service boards to be maintained.l OM signal flow in the EPS


2. After the OM signal is processed by the OMUa board, it is transmitted to the SCUaboard through the backplane of the MPS.

3. The SCUa board in the MPS transmits the OM signal to the SCUa board in the EPSthrough the Ethernet cable between the SCUa boards.

4. In the EPS, the SCUa board transmits the OM signal to the service boards to bemaintained.

l OM signal flow in the TCS


2. After being processed by the OMUa board, the OM signal is transmitted to the SCUaand Ater interface boards through the backplane of the MPS.

3. The OM signal is transmitted from the Ater interface board in the MPS to the Aterinterface board in the main TCS through the E1/T1 or optical cable between the Aterinterface boards. In the main TCS, the OM signal is transmitted from the Ater interfaceboard to the SCUa board through the backplane.




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4. In the main TCS, the backplane switches the signal from the SCUa board to the serviceboards to be maintained. The OM signal is transmitted from the SCUa board in themain TCS to the SCUa board in the extension TCS through the Ethernet cable betweenthe SCUa boards. In the extension TCS, the backplane switches the signal from theSCUa board to the service boards to be maintained.

Scenario 2: BM/TC Combined

In BM/TC combined mode, no TCS is configured. Figure 5-20 shows the OM signal flow.

Figure 5-20 OM signal flow (BM/TC combined)

As shown in Figure 5-20, the OM signal flow in the BSC6900 is as follows:

l OM signal flow in the MPS


2. After the OM signal is processed by the OMUa board, it is transmitted to the SCUaboard in the MPS through the backplane of the MPS.

3. The SCUa board then transmits the OM signal to the service boards to be maintained.

l OM signal flow in the EPS


2. After the OM signal is processed by the OMUa board, it is transmitted to the SCUaboard in the MPS through the backplane of the MPS.

3. The SCUa board in the MPS transmits the OM signal to the SCUa board in the EPSthrough the Ethernet cable between the SCUa boards.

4. In the EPS, the SCUa board transmits the OM signal to the service boards to bemaintained.

Scenario 3: A over IP

In BM/TC combined mode, no TCS is configured, and the TC function is performed by themedia gateway (MGW). The OM signal flow in A over IP mode is the same as that in BM/TCcombined mode.



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6 Transmission and Networking

About This Chapter

The transmission and networking between the BSC6900 and other NEs can be classified intothe following types: transmission and networking on the A/Gb interface, on the Abis interface,on the Ater interface, and on the Pb interface.

6.1 Transmission and Networking on the A/Gb InterfaceMultiple transmission and networking modes, including TDM-based networking on the A/Gbinterface and IP-based networking on the A/Gb interface, can be adopted between theBSC6900 and the core network (CN).

6.2 Transmission and Networking on the Abis InterfaceMultiple transmission and networking modes, including TDM-based networking on the Abisinterface, and IP-based networking on the Abis interface, can be adopted between theBSC6900 and the base station.

6.3 Transmission and Networking on the Ater InterfaceWhen the BSC6900 adopts the BM/TC separated mode, the Ater interface exists. Multipletransmission and networking modes, including TDM-based networking on the Ater interfaceand IP-based networking on the Ater interface, can be adopted between the BM subrack and theTC subrack.

6.4 Transmission and Networking on the Pb InterfaceIn external PCU configuration mode, TDM transmission can be applied to the Pb interfacebetween the BSC6900 and the PCU.

BSC6900 GSMTechnical Description 6 Transmission and Networking


6-1

6.1 Transmission and Networking on the A/Gb InterfaceMultiple transmission and networking modes, including TDM-based networking on the A/Gbinterface and IP-based networking on the A/Gb interface, can be adopted between theBSC6900 and the core network (CN).

6.1.1 TDM-Based Networking on the A/Gb InterfaceIn TDM-based networking mode, the BSC6900 and the MSC/MGW/SGSN communicate witheach other through the SDH/PDH network.

6.1.2 IP-Based Networking on the A/Gb InterfaceIn IP-based networking mode, the BSC6900 and the MSC/MGW/SGSN communicate with eachother through the IP network.

6.1.1 TDM-Based Networking on the A/Gb InterfaceIn TDM-based networking mode, the BSC6900 and the MSC/MGW/SGSN communicate witheach other through the SDH/PDH network.

Networking on the A InterfaceIn this networking mode, the BSC6900 and the MSC/MGW communicate with each otherthrough the SDH/PDH network. The EIUa/OIUa/POUc of the BSC6900 functions as the Ainterface board. The EIUa board provides E1/T1 ports, the OIUa board provides channelizedSTM-1 ports, and the POUc board provides channelized STM-1 ports and OC-3 ports.

The following describes the networking modes on the A interface in different TCS configurationmodes:

l Figure 6-1 shows the networking on the A interface in local TCS mode.

l Figure 6-2 shows the networking on the A interface in remote TCS mode.

Figure 6-1 TDM-based networking on the A interface in local TCS mode

Figure 6-2 TDM-based networking on the A interface in remote TCS mode

6 Transmission and NetworkingBSC6900 GSM



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Networking on the Gb InterfaceIn this networking mode, the BSC6900 and the SGSN communicate with each other through theFR network. The PEUa/POUc board of the BSC6900 functions as the Gb interface board. ThePEUa board provides E1/T1 ports, and the POUc board provides channelized STM-1 ports andOC-3 ports.

Figure 6-3 shows the networking on the Gb interface.

Figure 6-3 TDM-based networking on the Gb interface

Features of Networking ModesAdvantages: The networking is mature, QoS-assured, safe, and reliable. Telecom operators canmake full use of the SDH/PDH transmission network resources.

Disadvantages: The cost of the TDM networking mode is higher than that of the IP networkingmode.

6.1.2 IP-Based Networking on the A/Gb InterfaceIn IP-based networking mode, the BSC6900 and the MSC/MGW/SGSN communicate with eachother through the IP network.

IP over E1 NetworkingIn this networking mode, the PEUa/POUc board of the BSC6900 functions as the A interfaceboard. The PEUa board provides E1/T1 ports, and the POUc board provides channelized STM-1ports and OC-3 ports. Figure 6-4 shows the IP over E1 networking on the A interface. The Gbinterface does not support the IP over E1 networking mode.

Figure 6-4 IP over E1 networking on the A interface



6-3

IP over Ethernet NetworkingIn this networking mode, the BSC6900 and the CN communicate with each other through theIP network. The FG2a/FG2c board functions as the A/Gb interface board and provides FE/GEelectrical ports. The GOUa/GOUc board functions as the A interface board and provides GEoptical ports. The GOUc board functions as the Gb interface board and provides GE opticalports. See Figure 6-5.

Figure 6-5 IP over Ethernet networking on the A/Gb interface

Features of Networking ModesThese networking modes provide large-capacity bandwidth on the A/Gb interface, thus reducingthe CAPEX and OPEX.

6.2 Transmission and Networking on the Abis InterfaceMultiple transmission and networking modes, including TDM-based networking on the Abisinterface, and IP-based networking on the Abis interface, can be adopted between theBSC6900 and the base station.

6.2.1 TDM-Based Networking on the Abis InterfaceIn TDM-based networking mode, the BSC6900 and the base station communicate with eachother through the SDH/PDH network, and TDM transmission is applied to the Abis interface.6.2.2 IP-Based Networking on the Abis InterfaceIn IP-based networking mode, the BSC6900 and the base station communicate with each otherthrough the IP/SDH/PDH network, and layer 3 of the protocol stack for the Abis interface usesthe IP protocol.

6.2.1 TDM-Based Networking on the Abis InterfaceIn TDM-based networking mode, the BSC6900 and the base station communicate with eachother through the SDH/PDH network, and TDM transmission is applied to the Abis interface.

TDM-Based NetworkingIn this networking mode, the EIUa/OIUa/POUc board of the BSC6900 functions as the Abisinterface board. The EIUa board provides E1/T1 ports, the OIUa board provides channelized




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STM-1 ports, and the POUc board provides channelized STM-1 ports and OC-3 ports. Figure6-6 shows the TDM-based networking on the Abis interface.

Figure 6-6 TDM-based networking on the Abis interface



6.2.2 IP-Based Networking on the Abis InterfaceIn IP-based networking mode, the BSC6900 and the base station communicate with each otherthrough the IP/SDH/PDH network, and layer 3 of the protocol stack for the Abis interface usesthe IP protocol.

IP over E1 NetworkingIn this networking mode, the BSC6900 and the base station communicate with each other throughthe SDH/PDH network. The PEUa/POUc board functions as the Abis interface board. The PEUaboard provides E1/T1 ports, and the POUc board provides STM-1 ports and OC-3 ports. SeeFigure 6-7.

Figure 6-7 IP over E1 Networking

IP over Ethernet Networking (Layer 2)In this networking mode, the BSC6900 and the base station communicate with each other throughthe IP network, and the data transmitted between them is processed by the switch according tothe data link layer protocol. The FG2a/GOUa/FG2c/GOUc board of the BSC6900 functions asthe Abis interface board and provides FE/GE ports. Figure 6-8 shows the IP over Ethernetnetworking (layer 2).



6-5

Figure 6-8 IP over Ethernet networking (layer 2)

IP over Ethernet Networking (Layer 3)

In this networking mode, the BSC6900 and the base station communicate with each other throughthe IP network, and the data transmitted between them is processed by the router according tothe IP protocol. The FG2a/GOUa/FG2c/GOUc board of the BSC6900 functions as the Abisinterface board and provides FE/GE ports. Figure 6-9 shows the IP over Ethernet networking(layer 3).

Figure 6-9 IP over Ethernet networking (layer 3)

Features of Networking Modes

Advantages:l IP over E1 Networking

– Telecom operators can make full use of the SDH/PDH transmission network resources.

– The networking is mature, QoS-assured, safe, and reliable.

l IP over Ethernet Networking– The base station provides large-capacity bandwidth through FE/GE ports, thus

facilitating the upgrade and capacity expansion.– The transmission network supports the evolution from the GSM TDM network to the

IP network.

Disadvantages:l IP over E1 Networking




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This networking mode does not meet the requirements of the evolution from the telecomnetwork to the IP network.

l IP over Ethernet Networking

The QoS of the network cannot be guaranteed easily. Therefore, the end-to-end QoSmechanism must be adopted.

6.3 Transmission and Networking on the Ater InterfaceWhen the BSC6900 adopts the BM/TC separated mode, the Ater interface exists. Multipletransmission and networking modes, including TDM-based networking on the Ater interfaceand IP-based networking on the Ater interface, can be adopted between the BM subrack and theTC subrack.

6.3.1 TDM-Based Networking on the Ater InterfaceIn TDM-based networking mode, the BM subrack and the TC subrack communicate with eachother through the SDH/PDH network, and TDM transmission is applied to the Ater interface.

6.3.2 IP-Based Networking on the Ater InterfaceIn IP-based networking mode, the BM subrack and the TC subrack communicate with each otherthrough the SDH/PDH network, and IP transmission is applied to the Ater interface.

6.3.1 TDM-Based Networking on the Ater InterfaceIn TDM-based networking mode, the BM subrack and the TC subrack communicate with eachother through the SDH/PDH network, and TDM transmission is applied to the Ater interface.

TDM-Based Networking

In this networking mode, the EIUa/OIUa/POUc board of the BSC6900 functions as the Aterinterface board. The EIUa board provides E1/T1 ports, the OIUa board provides channelizedSTM-1 ports, and the POUc board provides channelized STM-1 ports and OC-3 ports. Figure6-10 shows the TDM-based networking on the Ater interface.

Figure 6-10 TDM-based networking on the Ater interface


Advantages: The networking is mature, QoS-assured, safe, and reliable. Telecom operators canmake full use of the SDH/PDH transmission network resources.




6-7

6.3.2 IP-Based Networking on the Ater InterfaceIn IP-based networking mode, the BM subrack and the TC subrack communicate with each otherthrough the SDH/PDH network, and IP transmission is applied to the Ater interface.

IP-Based Networking

In this networking mode, the POUc board of the BSC6900 functions as the Ater interface boardand provides channelized STM-1 ports and OC-3 ports. Figure 6-11 shows the IP-basednetworking on the Ater interface.

Figure 6-11 IP-based networking on the Ater interface


This networking mode provides large-capacity bandwidth on the Ater interface, thus reducingthe CAPEX and OPEX.

6.4 Transmission and Networking on the Pb InterfaceIn external PCU configuration mode, TDM transmission can be applied to the Pb interfacebetween the BSC6900 and the PCU.

TDM-Based Networking

In this networking mode, the EIUa/OIUa/POUc board of the BSC6900 functions as the Pbinterface board. The EIUa board provides E1/T1 ports, the OIUa board provides channelizedSTM-1 ports, and the POUc board provides channelized STM-1 ports and OC-3 ports. Figure6-12 shows the TDM-based networking on the Pb interface.

Figure 6-12 TDM-based networking on the Pb interface




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7 Parts Reliability

About This Chapter

The BSC6900 guarantees its operation reliability by means of board redundancy and portredundancy.

7.1 Concepts Related to Parts ReliabilityThe concepts related to parts reliability are board backup, port backup, resource pool, porttrunking, and port load sharing.

7.2 Board RedundancyBoard redundancy of the BSC6900 is of two types: board backup and resource pool.

7.3 Port RedundancyPort redundancy is of three types: optical port backup, FE/GE port backup, port load sharing,and port trunking.

BSC6900 GSMTechnical Description 7 Parts Reliability


7-1

7.1 Concepts Related to Parts ReliabilityThe concepts related to parts reliability are board backup, port backup, resource pool, porttrunking, and port load sharing.

7.1.1 BackupBackup is a process of synchronization between the active and standby units. In backup mode,two units of the same type work in active/standby mode, with one working as the active unit andthe other working as the standby unit. When the active unit is faulty, the active and standby unitsare switched over, and the standby unit takes over the tasks from the active unit. In this manner,the impact of unit failure on services is minimized.

7.1.2 Resource PoolA resource pool is an operating mode in which the resource nodes with the same characteristicsfunction as a resource pool. The resources in this pool are allocated and managed according tothe capabilities and status of each resource node.

7.1.3 Port TrunkingPort trunking is a technique based on which multiple physical ports are aggregated into onelogical port. This technique helps enhance the reliability of data transmission.

7.1.4 Port Load SharingPort load sharing is an operating mode in which the data streams that have the same destinationare distributed to different physical ports so that the load is shared by these ports.

7.1.1 BackupBackup is a process of synchronization between the active and standby units. In backup mode,two units of the same type work in active/standby mode, with one working as the active unit andthe other working as the standby unit. When the active unit is faulty, the active and standby unitsare switched over, and the standby unit takes over the tasks from the active unit. In this manner,the impact of unit failure on services is minimized.

Backup Typesl Board Backup

In board backup mode, two boards work in active/standby mode, with one working as theactive board and the other working as the standby board. Services can be processed byeither the active board only or both the active and standby boards. If the active board isfaulty, the BSC6900 automatically switches over the active and standby boards.

l Port Backup

In port backup mode, two ports work in active/standby mode, with one working as theactive port and the other working as the standby port. Data is transmitted through either theactive port only or both the active and standby ports. If the active port is faulty, theBSC6900 automatically switches over the active and standby ports.

Concepts Related to Backupl 1:1 Backup

The active and standby units work simultaneously. The normal operation of the system isensured as long as one unit works properly.

7 Parts ReliabilityBSC6900 GSM



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l 1+1 Hot BackupThe active and standby units work simultaneously and process the same services, but thestandby unit does not output the processing result. When the active unit is faulty, the standbyunit takes over the tasks from the active unit.

l 1+1 Warm BackupThe active and standby units work simultaneously, and the standby unit backs up thenecessary signaling and service data of the active unit. When the active and standby unitsare switched over, services are slightly affected. When the active unit is faulty, the standbyunit takes over the tasks from the active unit.

NOTE

When the active and standby units working in 1+1 warm backup mode are switched over, the establishedservices may or may not be disrupted. If the established services are not disrupted and the impact on theservices is acceptable, the impact on the services in 1+1 warm backup mode is equivalent to that in hotbackup mode.

l 1+1 Cold BackupThe active and standby units work simultaneously, but the standby unit does not back upthe necessary signaling and service data of the active unit. When the active and standbyunits are switched over, the established services are disrupted. When the active unit is faulty,the standby unit takes over the tasks from the active unit.

l N+1 Warm BackupThe active and standby N+1 units work simultaneously, with N units being active and oneunit being standby. The standby unit backs up the necessary signaling and service data ofthe active N units. When the active and standby units are switched over, services may beslightly affected. When any active unit is faulty, the standby unit takes over the tasks fromthis active unit.

l N+1 Cold BackupThe active and standby N+1 units work simultaneously, with N units being active and oneunit being standby. The standby unit does not back up the signaling and service data of theactive N units. When the active and standby units are switched over , the established servicesare disrupted. When any active unit is faulty, the standby unit takes over the tasks from thisactive unit.

NOTE

l The active and standby XPUa/XPUb boards of the BSC6900 work in 1:1 backup or 1+1 warm backup mode.

l The DPUa/DPUc/DPUd boards of the BSC6900 work in resource pool mode.

l Other active and standby boards of the BSC6900 work in 1+1 warm backup mode.

7.1.2 Resource PoolA resource pool is an operating mode in which the resource nodes with the same characteristicsfunction as a resource pool. The resources in this pool are allocated and managed according tothe capabilities and status of each resource node.

In resource pool mode, the system allocates resources nodes to the services that access theresource pool and provides proper service resources.

7.1.3 Port TrunkingPort trunking is a technique based on which multiple physical ports are aggregated into onelogical port. This technique helps enhance the reliability of data transmission.



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Port trunking works in trunk groups. Multiple physical links form a trunk group. If a physicallink in the trunk group becomes faulty, the data carried on the faulty link is transferred to otherlinks in the trunk group. Thus, the link failure does not disrupt the communication between bothends of the trunk group.

The traffic of the trunk group at the most can reach the total traffic on all the physical links inthe trunk group. Port trunking helps enhance transmission reliability and increase transmissionbandwidth.

7.1.4 Port Load SharingPort load sharing is an operating mode in which the data streams that have the same destinationare distributed to different physical ports so that the load is shared by these ports.

Port load sharing is mainly applicable to data transmission. Each of the ports working in loadsharing mode has an independent IP address so that each port can receive and transmit datapackets. If a port is faulty, the system stops distributing data to the faulty port and transfers thedata to other ports.

7.2 Board RedundancyBoard redundancy of the BSC6900 is of two types: board backup and resource pool.

7.2.1 Backup of EIUa BoardsWhen two EIUa boards are configured in adjacent slots in a subrack of the BSC6900, the twoboards can be configured to work in backup mode.

7.2.2 Backup of OIUa BoardsWhen two OIUa boards are configured in adjacent slots in a subrack of the BSC6900, the twoboards can be configured to work in backup mode.

7.2.3 Backup of PEUa BoardsWhen two PEUa boards are configured in adjacent slots in a subrack of the BSC6900, the twoboards can be configured to work in backup mode.

7.2.4 Backup of POUc BoardsWhen two POUc boards are configured in adjacent slots in a subrack of the BSC6900, the twoboards can be configured to work in board backup mode or port backup mode.

7.2.5 Backup of SCUa BoardsThe BSC6900 is configured with two SCUa boards in each subrack. The two boards work inbackup mode.

7.2.6 Backup of TNUa BoardsThe BSC6900 is configured with two TNUa boards in some subracks. The two boards work inbackup mode.

7.2.7 Backup of FG2a/FG2c BoardsWhen two FG2a/FG2c boards are configured in adjacent slots in a subrack of the BSC6900, thetwo boards can be configured to work in one of the following two modes: board backup with noport backup and board backup with port backup.

7.2.8 Backup of GCUa/GCGa BoardsThe BSC6900 is configured with two GCUa/GCGa boards in the MPS. The two boards workin backup mode.

7.2.9 Backup of GOUa/GOUc Boards




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When two GOUa/GOUc boards are configured in adjacent slots in a subrack of the BSC6900,the two boards can be configured to work in one of the following two modes: board backup withno port backup and board backup with port backup.

7.2.10 Backup of OMUa/OMUb BoardsWhen the BSC6900 is configured with two OMUa/OMUb boards in the MPS, the two boardswork in backup mode.

7.2.11 Backup of XPUa/XPUb BoardsWhen two XPUa/XPUb boards are configured in adjacent slots in a subrack of the BSC6900,the two boards can be configured to work in backup mode.

7.2.12 Resource Pool of DPUa/DPUc/DPUd BoardsThe DPUa/DPUc/DPUd boards of the BSC6900 and the Digital Signal Processors (DSPs) in allthe DPUa/DPUc/DPUd boards work in resource pool mode.

7.2.1 Backup of EIUa BoardsWhen two EIUa boards are configured in adjacent slots in a subrack of the BSC6900, the twoboards can be configured to work in backup mode.

When two EIUa boards are configured to work in backup mode, one EIUa board is active andthe other is standby. The standby board synchronizes its data with that on the active board inreal time.

The backup mode of the EIUa board is configurable when the ADD BRD command is used toadd an EIUa board.

Switchover Modes

The SWP BRD command can be used to switch over the active and standby EIUa boards.

Prerequisites for Switchover

The active and standby EIUa boards can be switched over only when one of the followingconditions is fulfilled:l The active EIUa board is reset, but the standby EIUa board works properly.

l The active EIUa board is faulty, but the standby EIUa board works properly.

Switchover Process

When the active and standby EIUa boards are switched over, the active EIUa board becomesstandby after being reset, and the other EIUa board becomes active.

Impact of Switchover on the System

The switchover between the active and standby EIUa boards slightly affects the TDMtransmission but does not disrupt ongoing services.

7.2.2 Backup of OIUa BoardsWhen two OIUa boards are configured in adjacent slots in a subrack of the BSC6900, the twoboards can be configured to work in backup mode.



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When two OIUa boards are configured to work in backup mode, one OIUa board is active andthe other is standby. The standby board synchronizes its data with that on the active board inreal time.

The backup mode of the OIUa board is configurable when the ADD BRD command is used toadd an OIUa board.

Switchover ModesThe SWP BRD command can be used to switch over the active and standby OIUa boards.

Prerequisites for SwitchoverThe active and standby OIUa boards can be switched over only when one of the followingconditions is fulfilled:l The active OIUa board is reset, and the standby OIUa board works properly.

l The active OIUa board is faulty, but the standby OIUa board works properly.

Switchover ProcessWhen the active and standby OIUa boards are switched over, the active OIUa board becomesstandby after being reset, and the other OIUa board becomes active.

Impact of Switchover on the SystemThe switchover between the active and standby OIUa boards slightly affects the TDMtransmission but does not disrupt ongoing services.

7.2.3 Backup of PEUa BoardsWhen two PEUa boards are configured in adjacent slots in a subrack of the BSC6900, the twoboards can be configured to work in backup mode.

When two PEUa boards are configured to work in backup mode, one PEUa board is active andthe other is standby. The standby board synchronizes its data with that on the active board inreal time. Y-shaped E1/T1 cables are used to connect the active and standby boards to the peerequipment. The E1/T1 ports on only the active board are used to transmit, receive, and processdata.

The backup mode of the PEUa board is configurable when the ADD BRD command is used toadd a PEUa board.

Switchover ModesThe SWP BRD command can be used to switch over the active and standby PEUa boards.

Prerequisites for SwitchoverThe active and standby PEUa boards can be switched over only when one of the followingconditions is fulfilled:l The active PEUa board is reset, but the standby PEUa board works properly.

l The active PEUa board is faulty, but the standby PEUa board works properly.




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Switchover Process

When the active and standby PEUa boards are switched over, the active PEUa board becomesstandby after being reset, and the other PEUa board becomes active.


The switchover between the active and standby PEUa boards slightly affects the datatransmission on PPP/MLPPP links but does not disrupt ongoing services.

7.2.4 Backup of POUc BoardsWhen two POUc boards are configured in adjacent slots in a subrack of the BSC6900, the twoboards can be configured to work in board backup mode or port backup mode.

When two POUc boards are configured to work in board backup mode, one POUc board is activeand the other is standby. The standby board synchronizes its data with that on the active boardin real time. Port backup adopts the MSP 1:1 or MSP 1+1 backup mode. Services are processedby the board where the active port is located. Active ports may be located on both the active andstandby boards because the switchover between the optical ports on the active and standby boardsdoes not affect the active/standby relation between the boards. In that case, both the active andstandby boards can process services. For details about the backup of the POUc optical ports, see7.3.1 Optical Port Backup.

The backup mode of the POUc board is configurable when the ADD BRD command is used toadd a POUc board. If Backup is set to YES, both the POUc boards and their optical ports workin backup mode. Therefore, the backup mode of the optical ports does not need to be configuredagain.

Switchover Modesl Automatic switchover: The active and standby POUc boards perform a switchover

automatically.

l Manual switchover: The SWP BRD command can be used to switch over the active andstandby POUc boards.


The active and standby POUc boards can be switched over only when one of the followingconditions is fulfilled:

l The active POUc board is reset, but the standby POUc board works properly.

l The active POUc board is faulty, but the standby POUc board works properly.

Switchover Process

When the active and standby POUc boards are switched over, the active POUc board becomesstandby after being reset, and the other POUc board becomes active.

NOTE

After an active/standby switchover, the BSC6900 determines the active and standby ports according to theMSP protocol strategy.



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The switchover between the active and standby POUc boards slightly affects data transmissionbut does not disrupt ongoing services.

7.2.5 Backup of SCUa BoardsThe BSC6900 is configured with two SCUa boards in each subrack. The two boards work inbackup mode.

When two SCUa boards are configured to work in backup mode, one SCUa board is active andthe other is standby. The standby board synchronizes its data with that on the active board inreal time. The data switched by the SCUa boards consists of the user-plane data and the control-plane data. The user-plane data is processed by the active and standby SCUa boards. The control-plane data is processed by the active SCUa board.

Switchover Modesl Automatic switchover: The active and standby SCUa boards perform a switchover

automatically.

l Manual switchover: The SWP BRD command can be used to switch over the active andstandby SCUa boards.


The active and standby SCUa boards can be switched over only when one of the followingconditions is fulfilled:

l The active SCUa board is reset, but the standby SCUa board works properly.

l The active SCUa board is faulty, but the standby SCUa board works properly.

l The clock source of the active SCUa board is faulty, but that of the standby SCUa boardworks properly.

Switchover Process

When the active and standby SCUa boards are switched over, the active SCUa board becomesstandby after being reset, and the other SCUa board becomes active.


The switchover between the active and standby SCUa boards does not affect ongoing services.

7.2.6 Backup of TNUa BoardsThe BSC6900 is configured with two TNUa boards in some subracks. The two boards work inbackup mode.

When two TNUa boards are configured to work in backup mode, one TNUa board is active andthe other is standby. The standby board synchronizes its data with that on the active board inreal time.




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Switchover Modesl Automatic switchover: The active and standby TNUa boards perform a switchover

automatically.l Manual switchover: The SWP BRD command can be used to switch over the active and

standby TNUa boards.

Prerequisites for SwitchoverThe active and standby TNUa boards can be switched over only when one of the followingconditions is fulfilled:l The active TNUa board is reset, but the standby TNUa board works properly.

l The active TNUa board is faulty, but the standby TNUa board works properly.

l The clock source of the active TNUa board is faulty, but that of the standby TNUa boardworks properly.

Switchover ProcessWhen the active and standby TNUa boards are switched over, the active TNUa board becomesstandby after being reset, and the other TNUa board becomes active.

Impact of Switchover on the SystemThe switchover between the active and standby TNUa boards does not affect ongoing services.

7.2.7 Backup of FG2a/FG2c BoardsWhen two FG2a/FG2c boards are configured in adjacent slots in a subrack of the BSC6900, thetwo boards can be configured to work in one of the following two modes: board backup with noport backup and board backup with port backup.

When two FG2a/FG2c boards are configured to work in board backup mode, one FG2a/FG2cboard is active and the other is standby. The standby board synchronizes its data with that onthe active board in real time.

The backup mode of the FG2a/FG2c board is configurable when the ADD BRD command isused to add an FG2a/FG2c board. If Backup is set to YES, the backup mode of the FG2a/FG2cboard is board backup with no port backup.

When the FG2a/FG2c boards are configured to work in board backup mode, you can run theADD ETHREDPORT command to set the backup mode of FE/GE ports. For details about thebackup mode of FE/GE ports, see 7.3.2 FE/GE Port Backup.

Switchover Modesl Automatic switchover: The active and standby FG2a/FG2c boards perform a switchover


standby FG2a/FG2c boards.

Prerequisites for SwitchoverThe active and standby FG2a/FG2c boards can be switched over only when one of the followingconditions is fulfilled:



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l The active FG2a/FG2c board is reset, but the standby FG2a/FG2c board works properly.

l The active FG2a/FG2c board is faulty, but the standby FG2a/FG2c board works properly.

Switchover Process

When the active and standby FG2a/FG2c boards are switched over, the active FG2a/FG2c boardbecomes standby after being reset, and the other FG2a/FG2c board becomes active.

NOTE

If the FG2a/FG2c boards work in board backup with port backup mode, after an active/standby switchover,the BSC6900 determines the active and standby ports and defines the port load sharing strategy.

Impact of Switchover on the Systeml When the FG2a/FG2c boards work in board backup with no port backup mode, The

switchover between the active and standby FG2a/FG2c boards does not affect ongoingservices.

l When the FG2a/FG2c boards work in board backup with port backup mode, the switchoverbetween the active and standby FG2a/FG2c boards slightly affects data transmission butdoes not disrupt ongoing services.

7.2.8 Backup of GCUa/GCGa BoardsThe BSC6900 is configured with two GCUa/GCGa boards in the MPS. The two boards workin backup mode.

When two GCUa/GCGa boards are configured to work in backup mode, one GCUa/GCGa boardis active and the other is standby. The active board processes services. The standby boardsynchronizes its data with the data on the active board in real time.

Switchover Modesl Automatic switchover: The active and standby GCUa/GCGa boards perform a switchover

automatically.

l Manual switchover: The SWP BRD command can be used to switch over the active andstandby GCUa/GCGa boards.


The active and standby GCUa/GCGa boards can be switched over only when one of the followingconditions is fulfilled:

l The active GCUa/GCGa board is reset, but the standby GCUa/GCGa board works properly.

l The active GCUa/GCGa board is faulty, but the standby GCUa/GCGa board worksproperly.

l The clock source of the active GCUa/GCGa board is faulty, but that of the standby GCUa/GCGa board works properly.

NOTE

The GCGa board supports the GPS clock. If the satellite card in the active GCGa board is faulty but thatin the standby GCGa board works properly, the active and standby GCGa boards are switched over.




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Switchover ProcessWhen the active and standby GCUa/GCGa boards are switched over, the active GCUa/GCGaboard becomes standby after being reset, and the other GCUa/GCGa board becomes active.

Impact of Switchover on the SystemThe switchover between the active and standby GCUa/GCGa boards does not affect ongoingservices.

7.2.9 Backup of GOUa/GOUc BoardsWhen two GOUa/GOUc boards are configured in adjacent slots in a subrack of the BSC6900,the two boards can be configured to work in one of the following two modes: board backup withno port backup and board backup with port backup.

When two GOUa/GOUc boards are configured to work in board backup mode, one board isactive and the other is standby. The standby board synchronizes its data with the data on theactive board in real time.

The backup mode of the GOUa/GOUc board is configurable when the ADD BRD command isused to add a GOUa/GOUc board. If Backup is set to YES, the backup mode of the GOUa/GOUc board is board backup with no port backup.

Switchover Modesl Automatic switchover: The active and standby GOUa/GOUc boards perform a switchover


standby GOUa/GOUc boards.

Prerequisites for SwitchoverThe active and standby GOUa/GOUc boards can be switched over only when one of thefollowing conditions is fulfilled:l The active GOUa/GOUc board is reset, but the standby GOUa/GOUc board works

properly.l The active GOUa/GOUc board is faulty, but the standby GOUa/GOUc board works

properly.

Switchover ProcessWhen the active and standby GOUa/GOUc boards are switched over, the active GOUa/GOUcboard becomes standby after being reset, and the other GOUa/GOUc board becomes active.

NOTE

If the GOUa/GOUc boards work in board backup with port backup mode, the BSC6900 determines theactive and standby ports and defines the port load sharing strategy after an active/standby switchover.

Impact of Switchover on the Systeml When the GOUa/GOUc boards work in board backup with no port backup mode, the

switchover between the active and standby GOUa/GOUc boards does not affect ongoingservices.



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l When the GOUa/GOUc boards work in board backup with port backup mode, theswitchover between the active and standby GOUa/GOUc boards slightly affects datatransmission but does not disrupt ongoing services.

7.2.10 Backup of OMUa/OMUb BoardsWhen the BSC6900 is configured with two OMUa/OMUb boards in the MPS, the two boardswork in backup mode.

When the OMUa/OMUb boards are configured to work in backup mode, one OMUa/OMUbboard is active and the other is standby. The active board processes services. The standby boardsynchronizes its data with the data on the active board in real time.

Switchover Modesl Automatic switchover: The active and standby OMUa/OMUb boards perform a switchover

automatically.l Manual switchover: The SWP OMU command can be used to switch over the active and

standby OMUa/OMUb boards.

Prerequisites for Switchoverl The active and standby OMUa/OMUb boards automatically perform a switchover only

when one of the following conditions is fulfilled:– The standby OMUa/OMUb board fails to detect the heartbeat information from the

active OMUa/OMUb board for five consecutive minutes.– The active OMUa/OMUb board fails to detect the virtual IP address for three

consecutive minutes, but the standby OMUa/OMUb board works properly.– Both the active and standby OMUa/OMUb boards work properly for one period, and

no switchover occurs during the period.NOTE

By default, the period for automatic switchover between the active and standby OMUa/OMUbboards is 90 days. You can also use the SET ASWPARA command to set the period for automaticswitchover.

l Manual switchover can be performed only when the standby OMUa/OMUb board worksproperly and the state of data synchronization between the active and standby OMUa/OMUb boards is Data synchronization is successful.

NOTE

You can use the DSP OMU command to query the state of data synchronization between the activeand standby OMUa/OMUb boards.

Switchover ProcessWhen the active and standby OMUa/OMUb boards are switched over, the active OMUa/OMUb board becomes standby, and the other OMUa/OMUb board becomes active.

Impact of Switchover on the SystemThe switchover between the active and standby OMUa/OMUb boards takes about one minute.The data synchronization after the switchover takes about two minutes. During the switchover,the communication between the operation and maintenance terminal and the host boards isinterrupted for about one or two minutes. At that time, you cannot perform operation and




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maintenance on the BSC6900. The switchover, however, does not affect ongoing services of theBSC6900.

7.2.11 Backup of XPUa/XPUb BoardsWhen two XPUa/XPUb boards are configured in adjacent slots in a subrack of the BSC6900,the two boards can be configured to work in backup mode.

When two XPUa/XPUb boards are configured to work in backup mode, one XPUa/XPUb boardis active and the other is standby. The active board processes services. The standby boardsynchronizes its data with that on the active board in real time.

Switchover Modesl Automatic switchover: The active and standby XPUa/XPUb boards perform a switchover


standby XPUa/XPUb boards.

Prerequisites for SwitchoverThe active and standby XPUa/XPUb boards can be switched over only when one of the followingconditions is fulfilled:l The active XPUa/XPUb board is reset, but the standby XPUa/XPUb board works properly.

l The active XPUa/XPUb board is faulty, but the standby XPUa/XPUb board works properly.

Switchover ProcessWhen the active and standby XPUa/XPUb boards are switched over, the active XPUa/XPUbboard becomes standby after being reset, and the other XPUa/XPUb board becomes active.

Impact of Switchover on the SystemThe switchover between the active and standby XPUa/XPUb boards does not affect ongoingservices.

7.2.12 Resource Pool of DPUa/DPUc/DPUd BoardsThe DPUa/DPUc/DPUd boards of the BSC6900 and the Digital Signal Processors (DSPs) in allthe DPUa/DPUc/DPUd boards work in resource pool mode.

Board Resource PoolAll the BSC6900DPUa/DPUc/DPUd boards of the BSC6900 work as a resource pool. TheBSC6900 appropriately schedules and allocates resources for services between the boards.

Services in a subrack are preferentially processed by DPU boards in the same subrack. If theDPU boards in the subrack are unavailable, the services are allocated to the DPU boards inanother subrack.

DSP Resource PoolAll the DSPs in the BSC6900DPUa/DPUc/DPUd boards of the BSC6900 work as a resourcepool. The status of the DSPs is managed by the Main Processing Unit (MPU) subsystem in the



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main control DPUa/DPUc/DPUd board. The MPU subsystem properly schedules and allocatesresources for services among the DSPs.

The priorities of DSPs to be allocated in descending order are DSPs in the same board, DSPs inthe same subrack, and DSPs in different subracks.

7.3 Port RedundancyPort redundancy is of three types: optical port backup, FE/GE port backup, port load sharing,and port trunking.

7.3.1 Optical Port BackupOptical port backup adopts the MSP 1:1 or MSP 1+1 backup mode.

7.3.2 FE/GE Port BackupWhen the FG2a/GOUa/FG2c/GOUc boards work in active/standby mode, the FE/GE ports onthe active and standby boards can be configured to work in port backup mode.

7.3.3 Port Load SharingThe FE/GE ports on the FG2a/GOUa/FG2c/GOUc board of the BSC6900 support load sharing.

7.3.4 Port TrunkingThe GE ports on the SCUa boards support port trunking.

7.3.1 Optical Port BackupOptical port backup adopts the MSP 1:1 or MSP 1+1 backup mode.

In MSP 1:1 backup mode, one optical port is active and the other is standby. Only the activeoptical port transmits and receives data.

In MSP 1+1 backup mode, one optical port is active and the other is standby. Both the activeand standby optical ports transmit data, but only the active optical port receives data.

The SET MSP command is used to set the attributes of MSP backup.

Switchover Modesl Automatic switchover: The active and standby optical ports perform a switchover

automatically.l Manual switchover: The SET MSPCMD command can be used to switch over the active

and standby optical ports.

Prerequisites for SwitchoverThe active and standby optical ports can be switched over only when one of the followingconditions is fulfilled:l A switchover at the peer end triggers a switchover at the local end.

l The board where the active optical port is located is reset.

l The active optical port is faulty, but the standby optical port works properly.

l The active board is faulty, but the standby board works properly.

l The optical transmission device connected to the active optical port is faulty, but the opticaltransmission device connected to the standby optical port works properly.




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Switchover ProcessWhen the active and standby optical ports are switched over, the active optical port stopsreceiving data and becomes standby, and the original standby optical port starts to receive dataand becomes active.

Impact of Switchover on the SystemIf the service traffic on the optical ports is heavy, the switchover between the active and standbyoptical ports slightly affects data transmission but does not disrupt ongoing services.

7.3.2 FE/GE Port BackupWhen the FG2a/GOUa/FG2c/GOUc boards work in active/standby mode, the FE/GE ports onthe active and standby boards can be configured to work in port backup mode.

In FE/GE port backup mode, one port is active and the other is standby. The active port transmitsand receives data.

When the boards work in active/standby mode, you can use the ADD ETHREDPORTcommand to configure the FE/GE ports on the active and standby boards to work in port backupmode.

Switchover Modesl Automatic switchover: The active and standby ports on the active and standby FG2a/GOUa/

FG2c/GOUc boards perform a switchover automatically.l Manual switchover: The SWP ETHPORT command can be used to switch over the active

and standby ports on the FG2a/GOUa/FG2c/GOUc boards.

Prerequisites for SwitchoverThe active and standby ports can be switched over only when one of the following conditionsis fulfilled:l The active port is faulty, but the standby port works properly.

l The active board is faulty, but the standby board works properly.

l The board where the active port is located is reset.

Switchover ProcessWhen the active and standby ports are switched over, the active port stops receiving and sendingdata and becomes standby, and the original standby port starts to receive and send data andbecomes active.

Impact of Switchover on the SystemIf the service traffic on the ports is heavy, the switchover between the active and standby portsslightly affects data transmission but does not disrupt ongoing services.

7.3.3 Port Load SharingThe FE/GE ports on the FG2a/GOUa/FG2c/GOUc board of the BSC6900 support load sharing.



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Prerequisites

The BSC6900 supports load sharing between FE/GE ports that are located either on the sameboard or on active and standby boards.

NOTE

l The BSC6900 does not support load sharing between the FE/GE ports on non-active/standby boards.

l The BSC6900 does not support load sharing between active and standby ports.

Working Principles

Load sharing between FE/GE ports is based on the user type. That is the data of a type of useris carried on one FE/GE port, and that of another type of user is carried on another FE/GE port.

NOTE

The data of one user is transmitted through only one FE/GE port.

Application Scenario

When the FE/GE ports of the BSC6900 work in load sharing mode, the data towards the sameIP address may be transmitted through different ports, and thus different IP routes must beconfigured. For example, load sharing between two FE/GE ports requires two IP routes. The IProutes must have the same destination IP address, subnet mask, and priority, but different next-hop IP addresses.

NOTE

l The ADD IPRT command can be used to add an IP route.

l The BSC6900 supports load sharing between a maximum of three FE/GE ports.

Benefitsl Data traffic is shared by the ports to avoid the condition where some ports are busy whereas

others are idle.l Load sharing enhances the reliability of data transmission.

7.3.4 Port TrunkingThe GE ports on the SCUa boards support port trunking.

Application of Port Trunking in the BSC6900

Port trunking is applicable to the switching subsystem of the BSC6900.l In the same subrack, the ports serving the communication between the SCUa and the other

boards work as a trunk group to implement port trunking.l The ports serving the communication between the SCUa boards in different subracks work

as a trunk group to implement port trunking.

Benefitsl In a trunk group, the bandwidth is evenly allocated to the GE ports, thus fulfilling load

balancing.




Issue 03 (2010-09-20)

l If a GE link in a trunk group is faulty, the data stream on the link is automatically switchedto other GE links.

l If an SCUa or another service board is faulty, no associated switchover occurs.



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Documents

BSC6900+GSM+Technical+Description(V900R012C01 03)