(7) Ethernet Service Introduction

Ethernet Service Introduction

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1 Basic Concepts..................................................................................Page

3

2 E t h e r n e t S e r v i c e

Classification... . . .. . .. . . . . . .. . . .. . . . .. . . . .. . . .. . .. . . . .. . . .. . . .. . . .. . . .. . Page 9



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Reference:

OptiX OSN 1500/2500/3500/7500 Intelligent Optical Transmission System

Hardware Description

OptiX OSN 1500/2500/3500/7500 Intelligent Optical Transmission System

Configuration Guide

ITU-T Recommendation G.8011/Y.1307

ITU-T Recommendation G.8010/Y.1306

ITU-T Recommendation G.7041/Y.1303 (GFP)

ITU-T Recommendation G.7042/Y.1305 (LCAS)



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The basic concepts about Ethernet over SDH (EOS) will be mentioned in chapter 1

including External port, VCTRUNK, Tag attribute etc.

Chapter 2 is the introduction of Ethernet service classification, the definitions,

applications and related functions of Ethernet services will be described.



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For OptiX Ethernet unit, we mainly focus on L2. VLAN (Virtual local area network)

is used to isolated different Ethernet signals which are carried by the same

physical link, for example the same port or VCTRUNK.

Frame structure of IEEE 802.1Q frame (VLAN)

The protocol type (PT) of IEEE 802.1Q frame is 0X8100, it is the

identification of the signal;

In two bytes VLAN label:

Priority 3 bits, 0~8 levels;

CFI 1 bit, Token-Ring encapsulation;

VLAN ID 12 bits, the range of VLAN ID is 0~4095.

DA SA PT=

0X8100

Ethernet

Data 6 6 2 N

VLAN

2



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Port is the external physical port of Ethernet unit. For example, in the front panel

of EFS4 there are four external physical ports (RJ45).

The working modes of the FE external port are Auto-negotiation, 10Mbps

(Half/Full duplex) and 100Mbps (Half/Full duplex);

For GE optical port the working modes are Auto-negotiation and

1000Mbps Full duplex.

For 10GE optical port the working modes are 10GE Full duplex LAN

(10.3125 Gbit/s) and 10GE Full duplex WAN (9.953 Gbit/s).

VCTRUNK is the logical internal port. One Ethernet unit provides several

VCTRUNKs connect with XCS unit.

VCTRUNK is built by VC (virtual container), for example if we bind five

VC12 into one VCTRUNK the rate of SDH side is around 10Mbps (2Mbps*5);

Normally virtual concatenation (VCAT) technology is used to bind VC into

VCTRUNK. VCAT is much more flexible than contiguous concatenation

(CCAT), all of the members status can be monitored by Ethernet unit. If

some of the members are failed, the LCAS (link Capacity Adjustment

Scheme) function executes the bandwidth adjustment immediately without

service interruption, however CCAT can not provide this function, all of the

bandwidth will be unavailable when member failure in one group.



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FE or GE signal is accessed by external port then the GFP-F encapsulation protocol

will adopt the Ethernet signal to VCTRUNK.

Two types of GFP encapsulation protocols:

GFP-F (Frame-mapped GFP)

For Ethernet service, e.g. FE/GE.

GFP-T (Transparent GFP)

For SAN (Storage Area Network) service, e.g. ESCON/FICON/Fiber channel.

Both of the external and internal ports can process Tag flag.



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All of the EFGS series boards can process the Tag flag.

Tag flag is used to identify the type of frames:

Tag frame: Signal contains VLAN;

Untag frame: Signal doesnt contain VLAN.

Caution:

EFGT series boards can not process the Tag flag.



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Most of the Ethernet boards provide three types of tag attributes: Tag aware,

Access and Hybrid. But some of the boards in Metro series can not provide

Hybrid, e.g. ET1.

Thought:

The VLAN ID of the frame accessed from the external port is 10, please fill

the blanks. If the frame doesnt contain VLAN ID please fill with -.

Port

VCTRUNK

Board

Port

types

Board

Port VCTRUNK

s VID

s VID Tag

attribute PVID

Tag

attribute PVID

EFS0 Access 11 Access 12

EFS4 Tag Access 12

EGS2

Hybrid 10 Hybrid 10

Tag Hybrid 12



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From ITU-T recommendation:

EPL: Ethernet Private Line

Feature: Point to point transmission without sharing.

EVPL: Ethernet Virtual Private Line

Feature: Point to point transmission with port or VCTRUNK sharing.

EPLAN: Ethernet Private LAN

Feature: Multi-points to multi-points transmission without sharing,

based on L2 switching.

EVPLAN: Ethernet Virtual Private Line

Feature: Multi-points to multi-points transmission with port or

VCTRUNK sharing, based on L2 switching;

Bandwidth utilization ratio is low.



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In the case of EPL services, a bandwidth is exclusively occupied by the service of a

user and the services of different users are isolated. In addition, the extra QoS

scheme and security scheme are not required.



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Services A & B access with different external ports then cross-connect to different

VCTRUNKs.

Point to point transmission without sharing, it provides the low latency and high

security point to point transmission.

The bandwidth for customers can be guaranteed, the max. bandwidth of point to

point EPL depends on the bandwidth of VCTRUNK.

Application: Private line for VIP user for example bank and government private

line.



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If the resource of port or Vctrunk is not enough, different users should share the

same port or Vctrunk. Hence, VLAN ID division/MPLS/QinQ technology should be

adopted to isolate different services.



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In ITU-T the V of EVPL stands for sharing. Share the external port or VCTRUNK

with different VLAN ID, MPLS label or S-VLAN.



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Service which is from the headquarters have to be transmitted to different

department.

Services access by NE 1will be transmitted by the same external port then cross-

connect to different VCTRUNKs, these two services are isolated with different

VLAN ID.

Different customers occupy different VCTRUNK, the bandwidth of VCTRUNK can

be guaranteed.

More than one customers share with one external port, so we should control the

bandwidth allocation of this external port.

For example two customers share with one FE port, if one customer use

90% bandwidth of the FE port then another one just can use 10%.

Normally we use CAR (Committed Access Rate) function to solve the

problem. We can manually configure the committed information rate (CIR)

for each of customer.

Application: the quantity of external port is limited, if the external ports are not

enough then we can try to implement the port shared EVPL service.



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Services A & B access with different external ports then cross-connect to the same

VCTRUNKs, these two services are isolated with different VLAN ID in the same

VCTRUNK.

Different customers occupy different external ports, the bandwidth of external

port can be guaranteed.

More than one customers share with one VCTRUNK, so we should control the

bandwidth allocation of this VCTRUNK.

For example two customers share with one VCTRUNK, if one customer use

90% bandwidth of this VCTRUNK then another one just can use 10%.

Normally we use CAR (Committed Access Rate) function to control the rate

of external port. We can manually configure the committed information

rate (CIR) for each of customer.

Application: the max. bandwidth of VCTRUNK is limited, if the total bandwidth is

not enough then the VCTRUNK shared EVPL can be used (Different users should

have different VLAN ID).



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The frame structure of MPLS:

For the MartinoE encapsulation protocol totally 22 bytes add to the

original frame;

The value of protocol type is 0x8847 for MPLS, this is the indication of

MPLS;

Totally there are two labels in one MatinoE frame, Tunnel and VC, each of

them is 4 bytes. In the tunnel and VC there are 20 bits used as the label

function. So the available range of label is 16~(220-1), 0~15 is reserved by

the system.

The port attribute of MPLS is P or PE:

PE: the edge of MPLS network, it is used to access the signal without

MPLS;

P: the internal port of MPLS network;

The operation of PE and P ports:

PE->P (Ingress): Add MPLS label;

P->PE (Egress): Discard MPLS label;

P->P (Transit): Exchange MPLS label.

MartinioE Format

DA SA 0x8847(0x8848

broadcast)

Ethernet

Data 6 6 2 N

VC

4

Tunnel

4



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When we configure the EVPL (MPLS) service, the default MPLS encapsulation is

MartinoE. It provides two stackable labels Tunnel and VC;

Different values of VC and Tunnel are used to isolate several Ethernet signal with

the same VLAN ID.



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QinQ technology is a VLAN stacking technology, which conforms to the

recommendation for S-VLAN in IEEE 802.1ad and is an expansion of VLAN

technology.

Advantages of QinQ technology:

Expands VLAN and alleviates VLAN resource insufficiency. For example, a

VLAN providing 4096 VLAN IDs can provide 4096 x 4096 VLANs after

VLAN stacking;

Extends LAN service to WAN, connecting the client network to the carrier

network and supporting transparent transmission.

QinQ frame format:

Customer VLAN label, defined as C-VLAN;

Server layer VLAN label, defined as S-VLAN.

DA

(6B)

SA

(6B)

TYPE(8100)

(2B)

S-VLAN

(2B)

TYPE(8100)

(2B)

C-VLAN

(2B)

Ethernet

Data



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EMS4 and EGS4 boards provide QinQ function, these boards provide 11 different

scenarios, depends on different applications;

For more information about QinQ Ethernet service configuration please refer to

the OptiX OSN 1500/2500/3500/7500 Intelligent Optical Transmission System

Configuration Guide.



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EPLAN service can provide multi-point to multi-point transmission without sharing.

Nowadays, only N2EFS4, N4EFS0, N1EMS4,N1EGS4,N3EGS4 and N1EAS2 could

support EPLAN (IEEE 802.1d Bridge) service.



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EPLAN is based on L2 switching, so in NE2, 3, 4 we should manually configure the

VB (Virtual bridge), it is the logical L2 lanswitch. So the traffic between NE2 and

NE4 will be forwarded by this VB, and its no need to configure the point to point

VCTRUNK between NE2 to NE4 any more. Also this solution can increase the

bandwidth utilization ratio. Compared with EPL service we need less point to

point VCTRUNKs.

Thought:

If NE3s VB is failed, what will happen to the EPLAN service?

If NE3s VB is failed, then the LAN service will be interrupted, the

VB in NE3 can not forward the data any more. Normally we should

configure another backup VB to prevent the VB failure. For example

we could configure a backup VB in NE1, and if NE3s VB is failed

the traffic can still go through with NE1s VB.

However, there is another problem which is called Broadcast

storm. After we configure 2 VBs in different NEs then loop occurs.

STP (Spanning Three Protocol) is used to solve this problem.



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VB is the logical L2 switch, it provides MAC address self-learning function.

MAC address self-learning function obviously improves the data forwarding

efficiency. How?

There is a CAM table in the L2 switch. Initially the CAM table is empty,

when the port of L2 switch receives the frame it will broadcast the frame

to all the other ports, at the same time it records the source MAC address

of the frame into the CAM table. The CAM table records the relation

between MAC address and port No.;

After the relation of MAC address and port is established, and the L2

switch will forward frames based on the destination address.



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The working mechanism of VB is the same as L2 switch, the ports of this logical

L2 switch are called LP.

Normally one LP can be bind in one VB, in case of the port attributes of MPLS is

PE. If the port attributes of MPLS is P then this LP can be shared with several VBs.



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The spanning tree protocol (STP) blocks certain ports to avoid the loop. Hence,

this can solve problems.

In addition, after being enabled, the STP logically modifies the network topology

structure to avoid broadcast storms.



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EVPLAN Service can provide multi-point to multi-point transmission with sharing.

In order to identify data from different users, VLAN/MPLS/QinQ technology

should be adopted.



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The MAC address self-learning and data forwarding of EPLAN service will be

based on VB + MAC address. Its no need to configure the VLAN filter table.

UNI port type of SVL VB: Tag Aware and Access

EVPLAN service forwards data through VB + MAC Address + VLAN/S-VLAN. The

VLAN filter table is necessary.

UNI port type of IVL VB: Tag Aware, Access and Hybrid

Ingress Filtering:

Enabled: The ingress filtering depends on the setting of the bridge

switching mode. When the bridge switching mode is set to IVL/Enable

Ingress Filtering, the ingress filtering is jointly enabled.

Disabled: The ingress filtering depends on the setting of the bridge

switching mode. When the bridge switching mode is set to SVL/Disable

Ingress Filtering, the ingress filtering is jointly disabled.



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The configuration of EVPLAN (802.1q) service is quite similar with EPLAN service.

The only difference is the VLAN filter table is necessary in EVPLAN (802.1q)

service.

IEEE 802.1q bridge supports isolation by using one layer of VLAN tags. It checks

the contents of the VLAN tags that are in the data frames and performs Layer 2

switching according to the destination MAC addresses and VLAN IDs.

In NE 3, the LPs of VB is port 1, port 2, VCTRUNK 1 and VCTRUNK 2. Data

forwarding will be based on different VLAN ID.

Thought:

Is it necessary to configure VB in NE 2 and NE 4? If no, what kind of

service should be configured in these two stations?



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The IEEE 802.1ad bridge supports data frames with two layers of VLAN tags. It

adopts the outer S-VLAN tags to isolate different VLANs and supports only the

mounted ports whose attributes are C-Aware or S-Aware. This bridge supports

the following switching modes:

This bridge does not check the contents of the VLAN tags that are in the

packets and performs Layer 2 switching according to the destination MAC

addresses of the packets.

This bridge checks the contents of the VLAN tags that are in the packets

and performs Layer 2 switching according to the destination MAC

addresses and the S-VLAN IDs of the packets.

In this case, the VoIP services need to be isolated from the HSI services. User M

does not need to communicate with user N. Since the C-VLAN of VoIP and HIS

service from user M and user N are the same, different S-VLAN should be

assigned to isolated the services.



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Thank you!

Documents

(7) Ethernet Service Introduction