BICC Slide

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1 Nokia Siemens Networks Presentation / Author / Date / Document Number

For public use IPR applies

Bearer Independent Call Control - BICCSwitching Core Network Signalling

M14/U4


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Document change history

Date Version Name Change comment

March 3, 08 1 Pubate Satienpoch Revised and update from M13 to M14/U4


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Bearer Independent Call Control - BICC

- BICC is call control protocol designed to transport call control signalling information,

independent of- used bearer technology (e.g. IP, ATM)

- signalling message transport technology (e.g. MTP, MTP3b, SIGTRAN)

- Separate set of procedure for call control signalling and bearer control signalling- Call Control Signalling : BICC (based on ISUP)

- Bearer Control Signalling : e.g. AAL2SIG, IPBCP

BICC

MTP3 MTP3b M3UA

MTP2 SAAL SCTP

MTP1 ATM IP


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BICC functional block

CSF

BCF

Call Control

Signalling

Call Control

Signalling

Bearer Control

Signalling

Bearer Control

SignallingBIWF

Bearer

SN

Call Bearer Control

Signalling (CBC)

CSF

BCF

Call Control

Signalling

Call Control

Signalling

Bearer Control

Signalling

Bearer Control

SignallingBIWF

SN

Call Bearer Control

Signalling (CBC)

CSF

CMN

Bearer

SN : Serving Node Call Service Function (CSF) with associated Bearer Control Function (BCF)

CMN : Call Mediation Node CSF without associated BCF

BIWF : Bearer Inter-working Function, provides BCF and media mapping/switching function


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BICC in 3GPP R4

In 3GPP Rel. 4, the user plane (bearer) and the control plane (signalling andcall control) are separated.

MGW takes care of the user plane and MSS controls it. BICC is to be implemented at Nc interface between MSC servers and MSS-

GCS

CBC (Call Bearer Control) signalling is implemented at Mc interface betweenMSC server and MGW.

MSCServer

H.248IP

MSCServer/ GCS

Mc

MGW

Nc

AAL2/AAL5ATM Nb

Mc

SigtranIP

BICC CS-2IP

MGWRTPIP

SigtranIP H.248

IP


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The vertical interface MGW-MSS (Mc in 3GPP) uses H.248 to convey the

bearer-related information. The needed bearer-information is transferred between MSSs in BICC throughAPM-mechanism

MGWMGW

MSC ServerMSC Server

IP

SCTP

M3UA

BICC

IAM

Sigtran

.

.IP address: 192.168.3.2Port: 5964

Codec: AMR mode 7...

Bearer informationcarried insignalling messages

Bearer cntr Bearer cntr

192.168.3.2/5964

BICC in 3GPP R4




Two ways to establish a bearer

1) Use separate bearer control signalling (ATM)

2) Tunnel bearer information in call control messages (IP)

Bearer Control Signalling

MSS MSSCall Control Signalling

BICC or SIP

AAL2 signalling

In IP backbone, no separatebearer signalling is used. Theinformation about the bearer istunneled in H.248 and SIP orBICC via the MSC Servers.

IPBCP is used.

H.248

In ATM backbone, bearer isestablished via separate bearer

control signalling. AAL2signalling is used.

H.248

MGW MGW




Bearer Establishment

Different alternatives for bearer establishment between MGWs are,

(Tunneled) Fast Forward setup [IP] (Tunneled) Delayed Forward setup [IP]

(Tunneled) Delayed Backward setup [IP]

(Non-tunneled) Per-call bearer setup in forward direction [ATM]

(Non-tunneled) Per-call bearer setup in backward direction [ATM]

Originating node always selects the bearer establishment method as well as theused bearer characteristics (BNC-char)




Bearer Establishment Modes - Non tunneled

Initial setup message

Bearer establishment direction

MSS MSS

Forward

Separate bearercontrol

protocol used(AAL2 signalling)


Bearer establishment direction

Backward

MSS

MGW

MSS

MGW




Bearer Establishment Modes - tunneled

No separate bearer control

protocol used

Initial setup message(Bearer Control Information)

MSS MSS

Fast setup

Delayedforward

Subsequent setup message

(Bearer Control Information)

MSS MSS

Response


Used e.g. when codec isnot known beforehand.

MGW MGW




Bearer Establishment Modes - tunneled

Response(Bearer Control Information)

MSS MSS

Delayedbackward


MGW MGW

No separate bearer controlprotocol used


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BICC call control related messages

Message Code Description

ACM 0000 0110 Address Complete Message

ANM 0000 1001 Answer Message

APM 0100 0001 Application Transport Message

COT 0000 0101 Continuity

CPG 0010 1100 Call Progress

CON 0000 0111 Connect

IDR 0011 0110 Identification Request

IRS 0011 0111 Identification Response

INF 0000 0100 Information

INR 0000 0011 Information Request


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BICC Maintenance related messages


CGB 0001 1000 Circuit / CIC Group Blocking

CGBA 0001 1010 Circuit / CIC Group Blocking Acknowledgement

GRS 0001 0111 Circuit / CIC Group Reset

GRA 0010 1001 Circuit / CIC Group Reset Acknowledgement

CGU 0001 1001 Circuit / CIC Group Unblocking

CGUA 0001 1011 Circuit / CIC Group UnblockingAcknowledgement

CQM 0010 1010 Circuit / CIC Group Query Message

CQR 0010 1011 Circuit / CIC Group Query Response


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BICC Maintenance related messages


CFN 0010 1111 Confusion

FAA 0010 0000 Facility Accepted

FAC 0011 0011 Facility

FRJ 0010 0001 Facility Reject

FAR 0001 1111 Facility Request

RSC 0001 0010 Reset Circuit / CIC message

UCIC 0010 1110 Unequipped Circuit Identification Code


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General BICC PDU format (ASN1)


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Format of BICC message

Formats and codes for BICC protocols are specified in ITU-T Q.1902.3

They are very much similar to ISUP.

BICC message (BICC PDU)


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CIC (Call Instance Code)

CIC in the BICC protocol is used to identify signalling relation between peer BICC

entities and associate all the PDUs to that relation. Bilateral agreement is required with regard to the CIC values provisioned.


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Application Transport Mechanism - APM

Allows applications to send application specific data between nodes using call

control messages Specified for BICC use in ITU-T Q.765.5

An application is running in the node besides call control instance

Application specific data may be sent in CC messages, or, if none is available, asa separate APM message.

Application specific data is send using APP (Application Transport Parameter)

appl

CC

appl

CC

CC message + application data

Application data

CC message + application data


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APM Functionality in Rel. 4

The application using APM for bearer control is called Bearer AssociationTransport - Application Service Element (BAT-ASE)

APM for BICC defines among others Action indicator (forward/backward)

BNC ID (reference used to associate the bearer with a call)

BIWF address (MGW address)

Codec(s)

Tunneling related information (used/not used, bearer control payload) Carried in APP parameter

MSS

IAMAPPpara

mparam

E.g. IAM or APMmessage

BAT-ASE

MSS

BAT-ASE


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Application Transport Parameter (APP)

Q.765.5

Q.1902.3


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List of identifiers


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Contents of identifiers

Action indicator

It can have codes like connect forward, connect backward etc.

Backbone network connection identifier

The content is bearer specific with maximum length of 4 octets (BNC_ID).

Interworking function address

Interworking function address is in NSAP format (BIWF Address).

Codec list

In the codec list, single codec information elements are listed in decreasing order of preference level.

Single codec

Single codec information element has a field called Organization identifier and codec information subfield.Subfield has information about the codec type and codec configuration.

Bearer Network Connection Characteristics

Codes here identifies the bearer used e.g. IP/RTP, AAL2, TDM etc.

Bearer control information

It contains PDU (Protocol Data Unit) of BCTP.

Bearer control tunnelling

It indicates whether tunnelling is used or not .

Bearer control unit identifier

It contains information about the BCU. It includes Network ID and Local BCU-ID.


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Action Indicator : used for a lot of categories ofindication Bearer Setup Control, for example

no indication

connect backward connect forward connect forward, no notification connect forward plus notification required

Bearer Setup Indication, for example connected

Codec Selection and Modification, for example selected codec modify codec successful codec modification codec modification failure mid-call codec negotiation

DTMF Interaction, for example start signal, notify start signal, no notify stop signal, notify stop signal, no notify


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Codec list

0x00 no indication

0x01 ITU-T

0x02 ETSI

Single codec IE

Single codec IE

Single codec IE

CODEC LIST

Organization Identifier

Single Codec IE

Codec type (codec ID)

Codec configuration

ITU-T ETSI

0x00 No indication 0x00 GSM FR

0x01 G.711 (64 kbps, A-law) 0x01 GSM HR

0x02 G.711 (64 kbps, u-law) 0x02 GSM EFR

0x03 GSM FR AMR

0x04 GSM HR AMR

0x05 UMTS AMR

0x06 UMTS AMR2

Organization ID Codec Type (Codec ID)


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BCTP Bearer Control Tunnelling Protocol

The BICC bearer control tunnelling protocol (BCTP) is a generic tunnelling

mechanism for the purpose of tunnelling bearer control protocols (BCP) over thehorizontal BICC interface between call control units (CCUs) and the vertical callbearer control protocol (CBC) interface between CCU and bearer control unit(BCU).

BCTP is defined in ITU-T Q.1990


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IPBCP IP Bearer Control Protocol

IPBCP is used for the exchange of media stream characteristics, port numbers and IPaddresses of the source and sink of a media stream to establish and allow the modifications

of IP bearers.

IPBCP uses the Session Description Protocol (SDP) defined in RFC 2327 to encode theinformation.

IPBCP uses four messages to convey information between peers

Request It is sent by a BIWF to initiate an IP bearer establishment or modificationrequest.

Accepted It is sent by a BIWF that receives an IP bearer establishment ormodification message if it accepts the request.

Confused It is sent by a BIWF in response to an IP bearer establishment ormodification message if it cannot process the received message.

Rejected- It is sent by a BIWF in response to an IP bearer establishment or

modification message if it rejects the request


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IPBCP

Each IPBCP message consists of following SDP fields:

Session and time description fields1. Protocol version (v)

2. Origin (o)

3. Session name (s)

4. Connection data (c)

5. Time (t)6. Session attribute (a)

Media description fields1. Media announcement (m)

2. Media attribute


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IPBCP in SDP format

Example content of IPBCP is shown in the figure

v= 0

o= - 0 0 IN IP4 10.33.16.136s= IP Tunnelingc= IN IP4 10.33.16.136t= 0 0a= ipbcp:1 Requestm= audio 1026 RTP/AVP 96a= rtpmap: 96 VND.3GPP.IUFP/16000

IPBCPSDP version (v) : 0

Owner/Creator, Session ID (o) :

Owner Username : -

Session ID : 0

Session Version : 0

Owner Network Type : IN

Owner Address Type : IPv4

Owner Address : 10.33.16.136

Session name (s): IP Tunneling

Connection Information (c):

Connection Network Type : IN

Connection Address Type : IPv4

Connection Address : 10.33.16.136

Time Description, active time (t) :

Session Start Time : 0

Session Stop Time : 0

Session Attribute (a) :

Session Attribute Fieldname : ipbcp

IPBCP protocol version : 1

IPBCP command type : Request

Media Description, name and address (m):

Media Type : audio

Media Port : 1026

Media Proto: RTP/AVP

Media Format : 96

Media Attribute (a) :

Media Attribute Fieldname : rtpmap

Media Format : 96

MIME Type : VND.3GPP.IUFP


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Codec Selection : Tandem Free Operation (TFO) vsTrancoder Free Operation (TrFO)

- TFO


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Codec Selection : Tandem Free Operation (TFO) vsTrancoder Free Operation (TrFO)

- TrFO : Codec negotiation using BICC APP parameter


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Successful BICC codec negotiation

Documents

BICC Slide