A.5.6 Signalling flows for termination to an ICS UE with CS media using I1 reference point when using an MSC Server enhanced for ICS

24.2923GPPIP Multimedia (IM) Core Network (CN) subsystem Centralized Services (ICS)Release 17Stage 3TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

Figure A.5.6-1 shows the termination of a call to a ICS UE via the I1 interface.

Figure A.5.6-1: ICS UE termination with CS media using I1 reference point when using an MSC Server enhanced for ICS

The details of the signalling flows are as follows:

1. SIP INVITE request (originating IM CN subsystem to intermediate IM CN subsystem entities in terminating network) – see example in table A.5.6-1

In this example, the originating UE initiates a voice call though its home IM CN subsystem (home1) with a terminating UE which is ICS capable which is in a different network (home2).

Table A.5.6-1: SIP INVITE request (originating IM CN subsystem to intermediate IM CN subsystem entities in terminating network)

INVITE sip:user2_public2@home2.net SIP/2.0

Via: SIP/2.0/UDP icscf2.home2.net;branch=z9hG4bK871y12.1, SIP/2.0/UDP scscf1.home1.net;branch=z9hG4bK332b23.1, SIP/2.0/UDP pcscf1.visited1.net;branch=z9hG4bK431h23.1, SIP/2.0/UDP [5555::aaa:bbb:ccc:ddd]:1357;comp=sigcomp;branch=z9hG4bKnashds7

Max-Forwards: 67

Route: <sip:scscf2.home2.net;lr>

Record-Route: <sip:scscf1.home1.net;lr>, <sip:pcscf1.visted1.net;lr>

P-Access-Network-Info: 3GPP-UTRAN-TDD; utran-cell-id-3gpp=234151D0FCE11

P-Asserted-Identity: "John Doe" <sip:user1_public1@home1.net>, <tel:+1-212-555-1111>

P-Charging-Vector: icid-value="AyretyU0dm+6O2IrT5tAFrbHLso=023551024"; orig-ioi=home1.net

P-Asserted-Service: urn:urn-7:3gpp-service.ims.icsi.mmtel

Accept-Contact: *;+g.3gpp.icsi_ref="urn%3Aurn-7%3gpp-service.ims.icsi.mmtel"

Privacy: none

From: <sip:user1_public1@home1.net>;tag=171828

To: <tel:+1-212-555-2222>

Call-ID: cb03a0s09a2sdfglkj490333

Cseq: 127 INVITE

Supported: 100rel, precondition, gruu

Contact: <sip:user1_public1@home2.net;gr=urn:uuid:f81d4fae-7dec-11d0-a765-00a0c91e6bf7>;;+g.3gpp.icsi_ref="urn%3Aurn-7%3gpp-service.ims.icsi.mmtel">

Allow: INVITE, ACK, CANCEL, BYE, PRACK, UPDATE, REFER, MESSAGE

Content-Type: application/sdp

Content-Length: (…)

v=0

o=- 2987933615 2987933615 IN IP6 5555::aaa:bbb:ccc:ddd

s=-

c=IN IP6 5555::aaa:bbb:ccc:ddd

t=0 0

m=audio 3456 RTP/AVP 97 0 96

b=AS:25.4

a=curr:qos local sendrcv

a=curr:qos remote none

a=des:qos mandatory local sendrecv

a=des:qos none remote sendrecv

a=rtpmap:97 AMR

a=fmtp:97 mode-set=0,2,5,7; mode-change-period=2

a=rtpmap:96 telephone-event

a=maxptime:20

NOTE 1: This example assumes the session was originated from a 3GPP Release 8 IMS UE and thus includes the ICSI value defined for MMTel in the Contact header and Accept Contact header. However, termination procedures for ICS do not rely upon the MMTel ICSI value being present in the incoming request.

2. SIP 100 (Trying) response (intermediate IM CN subsystem entities to originating IM CN subsystem)

The intermediate IM CN subsystem entities respond to the originating IM CN subsystem with a SIP 100 (Trying) response. There is no ICS specific content in this response.

3. Evaluation of initial filter criteria

The S-CSCF evaluates initial filter criteria for the served ICS user and as a result routes the SIP INVITE request towards the SCC AS.

NOTE 2: for terminating scenario, the SCC AS is configured as the last AS in the terminating iFC chain.

4. SIP INVITE request (intermediate IM CN subsystem entities to SCC AS) – see example in table A.5.6-4

As a result of iFC evaluation, the S-CSCF routes the INVITE request to the SCC AS.

Table A.5.6-4: SIP INVITE request (intermediate IM CN subsystem entities to SCC AS)

INVITE sip:user2_public2@home2.net SIP/2.0

Via: SIP/2.0/UDP scscf2.home2.net;branch=z9hG4bK332b33.1,SIP/2.0/UDP icscf2.home2.net;branch=z9hG4bK871y12.1, SIP/2.0/UDP scscf1.home1.net;branch=z9hG4bK332b23.1, SIP/2.0/UDP pcscf1.visited1.net;branch=z9hG4bK431h23.1, SIP/2.0/UDP [5555::aaa:bbb:ccc:ddd]:1357;comp=sigcomp;branch=z9hG4bKnashds7

Max-Forwards: 66

Route: <sip:sccas2.home2.net;lr>, <sip:cb03a0s09a2sdfglkj490333@scscf2.home2.net;lr>;orig-dialog-id="O:73935718_92645110-712786jd246395302d-zKE"

Record-Route: <sip:scscf2.home2.net;lr>, <sip:scscf1.home1.net;lr>, <sip:pcscf1.visited1.net;lr>

P-Access-Network-Info:

P-Asserted-Identity:

P-Charging-Vector:

P-Asserted-Service:

Accept-Contact:

Privacy:

From:

To:

Call-ID:

Cseq:

Supported:

Contact:

Allow:

Content-Type:

Content-Length:

v=0

o=-

s=-

5. SIP 100 (Trying) response (SCC AS to intermediate IM CN subsystem entities)

The SCC AS responds to the intermediate IM CN subsystem entities with a SIP 100 (Trying) response. There is no ICS specific content in this response.

6. Terminating Access Domain Selection

The SCC AS performs Terminating Access Domain Selection and chooses the CS domain for the setup of the media.

7. I1 INVITE request (using I1 Protocol to ICS UE B) – see example in Table A.5.6-9.

The I1 INVITE request is routed towards the called party ICS UE B.

The SCC AS initiates service control signalling in the IM CN subsystem towards the ICS UE by sending an I1 Invite message.

Specifically for this signalling flow, the I1 Invite message includes:

– Protocol Information = 0x11

– Message Type = I1 Invite

– Reason = MO (0x000)

– Call ID = (0x001)

– Sequence-ID = (0x1)

– To-id = [(international number), (12125556666)]

– From-id = [(international number), (12125551111)]

– SCC-AS-id information element = [(Code specific = E.164 number), (number digits = 1212556666)]. This is the allocated SCC AS PSI DN

– Session-identifier information element = [(Code specific = E.164 number), (number digits = 1212557777)]. This is the allocated SCC AS STI

8. SETUP message (ICS UE B to MSC Server enhanced for ICS)

The ICS UE B inititates bearer setup in the CS domain by sending a SETUP message to the MSC Server enhanced for ICS.

Specifically for this signalling flow, the SETUP message includes:

– Called Party Number information element = = [(Numbering plan identifier = ISDN/telephony numbering plan), (type of number = international number ), (Number digits = 1212556666)]. The Called Party Number information element is set to the UAI PSI DN.

– Bearer Capability information element = [(information transfer capability = speech), (speech versions = FR AMR, GSM EFR, GSM FR)]

– Supported Codec List information element = {[(SysID 1 = UMTS), (Codec Bitmap for SysID 1 = UMTS AMR 2)], [(SysID 2 = GSM), (Codec Bitmap for SysID 2 = FR AMR, GSM EFR, GSM FR)]}

The MSC Server enhanced for ICS knows the calling party number corresponding to the ICS UE B.

9. CALL PROCEEDING message (MSC Server enhanced for ICS to ICS UE B)

Upon receipt of the SETUP message from the ICS UE B, the MSC Server enhanced for ICS responds with a CALL PROCEEDING message. There is no ICS specific content in this message.

10. SIP INVITE request (MSC Server enhanced for ICS to intermediate IM CN subsystem entities) – see example in table A.5.6-13.

The MSC Server enhanced for ICS maps the received SETUP message to a SIP INVITE request which is routed towards the intermediate IM CN subsystem entities. The SIP INVITE request is addressed to the IUA PSI DN in the Request-URI.

Table A.5.6-10: SIP INVITE request (MSC Server enhanced for ICS to intermediate IM CN subsystem entities)

INVITE tel:+1-212-555-6666 SIP/2.0

Via: SIP/2.0/UDP msc2.home2.net;branch=z9hG4bKnashds7

Max-Forwards: 70

Route: <sip:icscf2.home2.net:lr>

P-Asserted-Identity: <tel: +1-212-555-2222>

P-Charging-Vector: icid-value="AyretyU0dm+6O2IrT5tAFrbHLso=023551024"; orig-ioi=home2.net

P-Access-Network-Info:

Privacy: none

From: <tel: +1-212-555-2222>;tag=171828

To: <tel:+1-212-555-6666>

Call-ID: f81d4fae-7dec-11d0-a765-00a0c91e6bf6

Cseq: 127 INVITE

Supported: 100rel, precondition

Require: sec-agree

Proxy-Require: sec-agree

Security-Verify: ipsec-3gpp; q=0.1; alg=hmac-sha-1-96; spi=87654321; port=7531

Contact: <sip:user2_public1@home.net;gr=urn:uuid:f81e4tye-7dec-11d0-a123-00a0c91d4rf7>;

Allow: INVITE, ACK, CANCEL, BYE, PRACK, UPDATE, REFER, MESSAGE

Content-Type: application/sdp

Content-Length: (…)

v=0

o=- 2987933615 2987933615 IN IP6 5555::aaa:bbb:ccc:eee

c=IN IP6 5555::aaa:bbb:ccc:eee

t=0 0

m=audio 3456 RTP/AVP 97 96

b=AS:25.4

a=curr:qos local sendrecv

a=curr:qos remote none

a=des:qos mandatory local sendrecv

a=des:qos none remote sendrecv

a=rtpmap:97 AMR

a=fmtp:97 mode-set=0,2,5,7; mode-change-period=2

a=rtpmap:96 telephone-event

a=maxptime:20

Request-URI: UAI PSI DN as received in the SETUP message.

P-Asserted-Identity header: The MSC Server enhanced for ICS inserts the tel URI containing the subscriber number, as received from the ICS UE B.

SDP: The SDP contains preconfigured set of codecs supported by the MGW.

11. SIP 100 (Trying) response (intermediate IM CN subsystem entities to MSC Server enhanced for ICS)

The intermediate IM CN subsystem entities respond to the MSC Server enhanced for ICS with a SIP 100 (Trying) response. There is no ICS specific content in this response.

12. SIP INVITE request (intermediate IM CN subsystem entities to SCC AS) – see example in Table A.5.6-15

The SIP INVITE request is sent to the SCC AS.

Table A.5.6-12: SIP INVITE request (MSC Server enhanced for ICS to intermediate IM CN subsystem entities)

INVITE tel:+1-212-555-6666 SIP/2.0

Via: SIP/2.0/UDP scscf2.home2.net;branch=z9hG4bK332b33.1,SIP/2.0/UDP icscf2.home2.net;branch=z9hG4bK871y12.1, SIP/2.0/UDP msc2.home2.net;branch=z9hG4bKnashds7

Max-Forwards: 68

Route: <sip:sccas2.home2.net:lr>, <sip:scscf2.home2.net;lr>;orig-dialog-id="yuflsae80r3rb3fh31ondyr829cnyr381cn932YDWref0w0-wwtg374"

Record-Route: <sip:scscf2.home2.net;lr>

P-Asserted-Identity:

P-Charging-Vector:

P-Access-Network-Info:

Privacy:

From:

To:

Call-ID:

Cseq:

Supported:

Require:

Proxy-Require:

Security-Verify:

Contact:

Allow:

Content-Type:

Content-Length: (…)

o=-

13. SIP 100 (Trying) response (SCC AS to intermediate IM CN subsystem entities)

The SCC AS responds to the intermediate IM CN subsystem entities with a SIP 100 (Trying) response. There is no ICS specific content in this response.

14. SIP 200 (OK) response (SCC AS to intermediate IM CN subsystem entities) – see example in table A.5.6-17.

The SCC AS responds to the SIP INVITE request with a SIP 200 (OK) response that includes an SDP answer.

Table A.5.6-14: SIP 200 (OK) response (SCC AS to intermediate IM CN subsystem entities)

SIP/2.0 200 OK

Via: SIP/2.0/UDP scscf2.home2.net;branch=z9hG4bK332b33.1,SIP/2.0/UDP icscf2.home2.net;branch=z9hG4bK871y12.1, SIP/2.0/UDP msc2.home2.net;branch=z9hG4bKnashds7

Record-Route: <sip:scscf2.home2.net;lr>

P-Access-Network-Info:

Privacy: none

From: <tel: +1-212-555-2222>;tag=171828

To: <tel:+1-212-555-6666>

Call-ID: f81d4fae-7dec-11d0-a765-00a0c91e6bf6

CSeq:

Require: 100rel, precondition

Contact:

Allow: INVITE, ACK, CANCEL, BYE, PRACK, UPDATE, REFER, MESSAGE

Content-Type: application/sdp

Content-Length: (…)

v=0

o=- 2987933623 2987933623 IN IP6 5555::ggg:fff:aaa:bbb

s=-

c=IN IP6 5555::ggg:fff:aaa:bbb

t=0 0

m=audio 3456 RTP/AVP 97 96

b=AS:25.4

a=curr:qos local sendrcv

a=curr:qos remote sendrcv

a=des:qos mandatory local sendrecv

a=des:qos mandatory remote sendrecv

a=rtpmap:97 AMR

a=fmtp:97 mode-set=0,2,5,7; mode-change-period=2

a=maxptime:20

15. SIP 200 (OK) response (intermediate IM CN subsystem to MSC Server enhanced for ICS)

The intermediate IM CN subsystem entities route the SIP 200 (OK) response to the MSC Server enhanced for ICS.

16. CONNECT message (MSC Server enhanced for ICS to ICS UE B)

The enhance MSC Server maps the received SIP 200 (OK) response to a CONNECT message. There is no ICS specific content in this message.

17. CONNECT ACKNOWLEDGEMENT message (ICS UE B to MSC Server enhanced for ICS)

The ICS UE A sends a CONNECT ACKNOWLEDGMENT message upon receiving the CONNECT message. There is no ICS specific content in this message.

18-19. SIP ACK request (MSC Server enhanced for ICS to SCC AS via intermediate IM CN subsystem entities)

The MSC Server enhanced for ICS interworks the received CONNECT ACKNOWLEDGEMENT message to a SIP ACK request which is routed to the SCC AS via the intermediate IM CN subsystem entities. There is no ICS specific content in this response.

20. I1 PROGRESS response (ICS UE B to SCC AS via I1 Protocol) – see example in table A.5.6-23.

The ICS UE B responds to the received I1 INVITE request with I1 Progress response.

Specifically for this signalling flow, the I1 Progress message includes:

– Protocol Information = 0x11

– Message Type = I1 Progress

– Reason = 0x0 180

– Call ID = (0x001)

– Sequence-ID = 0x1

21-22. SIP 180 (Ringing) response (SCC AS to originating IM CN subsystem via intermediate IM CN subsystem entities)

The SCC AS routes the received SIP 180 (Ringing) response towards the originating network and the calling party.

23. I1 SUCCESS response (ICS UE B to SCC AS via I1 Protocol) – see example in table A.5.6-27

The ICS UE B responds to the received initial I1 INVITE request with a I1 SUCCESS response.

Specifically for this signalling flow, the I1 Success message includes:

– Protocol Information = 0x11

– Message Type = I1 Success

– Reason = 0x0

– Call ID = (0x001)

– Sequence-ID = 0x3

24. SIP 200 (OK) response (intermediate IM CN subsystem entities to SCC AS)

The SIP 200 (OK) response and final SDP answer from the ICS UE is routed towards the SCC AS.

25-26. SIP 200 (OK) response (SCC AS to originating IM CN subsystem via intermediate IM CN subsystem entities)

The SIP 200 OK response is routed towards the originator of the session in the originating IM CN subsystem.

27-28. SIP ACK request (originating IM CN subsystem to SCC AS via intermediate IM CN subsystem entities and SCC AS)

The originating IM CN subsystem sends a SIP ACK request to the SCC AS via the intermediate IM CN subsystem entities. There is no ICS specific content in this response.

A.5.7 Signalling flows for termination to an ICS UE with CS media using I1 reference point when using an MSC server enhanced for ICS and UE assisted T-ADS

Figure A.5.7-1 shows the termination of a call to an ICS UE using CS bearers controlled through the IM CN subsystem.

Figure A.5.7-1: ICS UE termination with CS media using I1 reference point when using an MSC server – UE assisted T-ADS

The details of the signalling flows are as follows:

1-13: These steps are identical to steps 1-5 described in subclause A.5.5.

6. Terminating Access Domain Selection

The SCC AS performs initial T-ADS selecting IMS for the service control signalling when UE-B is registered in the IMS.

7. I1 Invite message (SCC AS Via I1 Protocol to ICS UE B)

The I1 Invite message is routed towards the called party ICS UE B.

The SCC AS initiates service control signalling in the IM CN subsystem towards the ICS UE by sending an I1 Invite message.

Specifically for this signalling flow, the I1 Invite message includes:

– Protocol Information = 0x11

– Message Type = I1 Invite

– Reason = MO (0x000)

– Call ID = (0x001)

– Sequence-ID = (0x1)

– To-id = [(international number), (12125556666)]

– From-id = [(international number), (12125551111)]

– SCC-AS-id information element = [(Code specific = E.164 number), (number digits = 1212556666)]. This is the allocated SCC AS PSI DN

– Session-identifier information element = [(Code specific = E.164 number), (number digits = 1212557777)]. This is the allocated SCC AS STI

8. I1 Progress message (ICS UE to SCC AS)

The ISC UE generates an I1 Progress message based upon the received I1 INVITE request.

Specifically for this signalling flow, the I1 Progress message includes:

– Protocol Information = 0x11

– Message Type = I1 Progress

– Reason = 0x0 183

– Call ID = (0x001)

– Sequence-ID = 0x1

9. CC SETUP message (ICS UE B to MSC server)

The ICS UE B inititates bearer setup in the CS domain by sending a CC SETUP message to the MSC server.

Specifically for this signalling flow, the CC SETUP message includes:

– Bearer Capability information element = [(information transfer capability = speech), (speech versions = FR AMR, GSM EFR, GSM FR)]

– Supported Codec List information element = {[(SysID 1 = UMTS), (Codec Bitmap for SysID 1 = UMTS AMR 2)], [(SysID 2 = GSM), (Codec Bitmap for SysID 2 = FR AMR, GSM EFR, GSM FR)]}

The MSC server knows the calling party number corresponding to the ICS UE B.

10. CC CALL PROCEEDING message (MSC server to ICS UE B)

Upon receipt of the CC SETUP message from the ICS UE B, the MSC server responds with a CC CALL PROCEEDING message. There is no ICS specific content in this message.

11. SIP INVITE request (MSC server to intermediate IM CN subsystem entities via MGCF) – see example in table A.5.7-11.

The MSC server maps the received CC SETUP message an IAM. The MGCF then maps this to a SIP INVITE request which is routed towards the intermediate IM CN subsystem entities. The SIP INVITE request is addressed to the IUA PSI DN in the Request-URI.

Table A.5.7-11: SIP INVITE request (MSC server to intermediate IM CN subsystem entities via MGCF)

INVITE tel:+1-212-555-6666 SIP/2.0

Via: SIP/2.0/UDP mgcf2.home2.net;branch=z9hG4bKnashds7

Max-Forwards: 70

Route: <sip:icscf2.home2.net:lr>

P-Asserted-Identity: <tel: +1-212-555-2222>

P-Charging-Vector: icid-value="AyretyU0dm+6O2IrT5tAFrbHLso=023551024"; orig-ioi=home2.net

P-Access-Network-Info:

Privacy: none

From: <tel: +1-212-555-2222>;tag=171828

To: <tel:+1-212-555-6666>

Call-ID: f81d4fae-7dec-11d0-a765-00a0c91e6bf6

Cseq: 127 INVITE

Supported: 100rel, precondition

Require: sec-agree

Proxy-Require: sec-agree

Security-Verify: ipsec-3gpp; q=0.1; alg=hmac-sha-1-96; spi=87654321; port=7531

Contact:

Allow: INVITE, ACK, CANCEL, BYE, PRACK, UPDATE, REFER, MESSAGE

Content-Type: application/sdp

Content-Length: (…)

v=0

o=- 2987933615 2987933615 IN IP6 5555::aaa:bbb:ccc:fff

c=IN IP6 5555::aaa:bbb:ccc:fff

t=0 0

m=audio 3456 RTP/AVP 97 96

b=AS:25.4

a=curr:qos local sendrecv

a=curr:qos remote none

a=des:qos mandatory local sendrecv

a=des:qos none remote sendrecv

a=rtpmap:97 AMR

a=fmtp:97 mode-set=0,2,5,7; mode-change-period=2

a=rtpmap:96 telephone-event

a=maxptime:20

Request-URI: UAI PSI DN as received in the CC SETUP message.

P-Asserted-Identity header: The MSC server inserts the tel-URI containing the subscriber number, as received from the ICS UE B.

SDP: The SDP contains preconfigured set of codecs supported by the MGW.

12. SIP 100 (Trying) response (intermediate IM CN subsystem entities to MGCF )

The intermediate IM CN subsystem entities respond to the MGCF with a SIP 100 (Trying) response. There is no ICS specific content in this response.

13. SIP INVITE request (intermediate IM CN subsystem entities to SCC AS) – see example in table A.5.7-13

The SIP INVITE request is sent to the SCC AS.

Table A.5.7-13: SIP INVITE request (intermediate IM CN subsystem entities to SCC AS)

INVITE tel:+1-212-555-6666 SIP/2.0

Via: SIP/2.0/UDP scscf2.home2.net;branch=z9hG4bK332b33.1,SIP/2.0/UDP icscf2.home2.net;branch=z9hG4bK871y12.1, SIP/2.0/UDP mgcf2.home2.net;branch=z9hG4bKnashds7

Max-Forwards: 68

Route: <sip:sccas2.home2.net:lr>, <sip:scscf2.home2.net;lr>;orig-dialog-id="yuflsae80r3rb3fh31ondyr829cnyr381cn932YDWref0w0-wwtg374"

Record-Route: <sip:scscf2.home2.net;lr>

P-Asserted-Identity:

P-Charging-Vector:

P-Access-Network-Info:

Privacy:

From:

To:

Call-ID:

Cseq:

Supported:

Require:

Proxy-Require:

Security-Verify:

Contact:

Allow:

Content-Type:

Content-Length: (…)

o=-

14. SIP 100 (Trying) response (SCC AS to intermediate IM CN subsystem entities)

The SCC AS responds to the intermediate IM CN subsystem entities with a SIP 100 (Trying) response. There is no ICS specific content in this response.

15. SIP 200 (OK) response (SCC AS to intermediate IM CN subsystem entities) – see example in table A.5.7-15.

The SCC AS responds to the SIP INVITE request with a SIP 200 (OK) response that includes an SDP answer. The SDP shows local preconditions as received in the INVITE in step 4.

Table A.5.7-15: SIP 200 (OK) response (SCC AS to intermediate IM CN subsystem entities)

SIP/2.0 200 OK

Via: SIP/2.0/UDP scscf2.home2.net;branch=z9hG4bK332b33.1,SIP/2.0/UDP icscf2.home2.net;branch=z9hG4bK871y12.1, SIP/2.0/UDP mgcf2.home2.net;branch=z9hG4bKnashds7

Record-Route: <sip:scscf2.home2.net;lr>

P-Access-Network-Info:

Privacy: none

From: <tel: +1-212-555-2222>;tag=171828

To: <tel:+1-212-555-6666>

Call-ID: f81d4fae-7dec-11d0-a765-00a0c91e6bf6

CSeq:

Require: 100rel, precondition

Contact:

Allow: INVITE, ACK, CANCEL, BYE, PRACK, UPDATE, REFER, MESSAGE

Content-Type: application/sdp

Content-Length: (…)

v=0

o=- 2987933623 2987933623 IN IP6 5555::aaa:bbb:ccc:ddd

s=-

c=IN IP6 5555::aaa:bbb:ccc:ddd

t=0 0

m=audio 3456 RTP/AVP 97 96

b=AS:25.4

a=curr:qos local sendrcv

a=curr:qos remote sendrcv

a=des:qos mandatory local sendrecv

a=des:qos mandatory remote sendrecv

a=rtpmap:97 AMR

a=fmtp:97 mode-set=0,2,5,7; mode-change-period=2

a=maxptime:20

16. SIP 200 (OK) response (intermediate IM CN subsystem to MSC server via MGCF)

The intermediate IM CN subsystem entities route the SIP 200 (OK) response to the MGCF. The MGCF maps the SIP (200) OK to a ISUP ANM which is sent to the MSC server.

17. CC CONNECT message (MSC server to ICS UE B)

The MSC server maps the received SIP 200 (OK) response to a CC CONNECT message. There is no ICS specific content in this message.

18. CC CONNECT ACKNOWLEDGEMENT message (ICS UE B to MSC server)

The ICS UE A sends a CC CONNECT ACKNOWLEDGMENT message upon receiving the CC CONNECT message. There is no ICS specific content in this message.

19-20. SIP ACK request (MGCF to SCC AS via intermediate IM CN subsystem entities)

The MGCF sends a SIP ACK request which is routed to the SCC AS via the intermediate IM CN subsystem entities. There is no ICS specific content in this response.

21. I1 Progress response (ICS UE B to SCC AS via I1 Protocol)

The ICS UE B responds to the received I1 Invite message with an I1 Progress message.

Specifically for this signalling flow, the I1 Progress message includes:

– Protocol Information = 0x11

– Message Type = I1 Progress

– Reason = 0x0 180

– Call ID = (0x001)

– Sequence-ID = 0x1

22-23. SIP 180 (Ringing) response (SCC AS to originating IM CN subsystem via intermediate IM CN subsystem entities)

The SCC AS routes the received SIP 180 (Ringing) response towards the originating network and the calling party.

24. I1 Success message (ICS UE B to SCC AS via I1 Protocol)

The ICS UE B responds to the received initial I1 Invite message with an I1 Success message.

Specifically for this signalling flow, the I1 Success message includes:

– Protocol Information = 0x11

– Message Type = I1 Success

– Reason = 0x0

– Call ID = (0x001)

– Sequence-ID = 0x3

25-26. SIP 200 (OK) response (SCC AS to originating IM CN subsystem via intermediate IM CN subsystem entities) – see example in table A.5.7-26

The SIP 200 (OK) response is routed towards the originator of the session in the originating IM CN subsystem. This SIP 200 (OK) response includes an SDP answer the correponds to the SDP received from the MSC server and indicates that local preconditions are met.

Table A.5.7-26: SIP 200 (OK) response (ICS UE B to intermediate IM CN subsystem entities)

SIP/2.0 200 OK

Record-Route: <sip:pcscf2.visited2.net;lr>, <sip:scscf2.home2.net;lr>

P-Access-Network-Info: 3GPP-UTRAN-FDD; utran-cell-id-3gpp=234151D0FCE11

Privacy: none

From: <tel: +1-212-555-1111>;tag=171828

To: <tel:+1-212-555-2222>

Call-ID: cb03a0s09a2sdfglkj490333

CSeq:

Require: 100rel, precondition

Contact:

Allow: INVITE, ACK, CANCEL, BYE, PRACK, UPDATE, REFER, MESSAGE

Content-Type: application/sdp

Content-Length: (…)

v=0

o=- 2987933623 2987933623 IN IP6 5555::aaa:bbb:ccc:eee

s=-

c=IN IP6 5555::aaa:bbb:ccc:eee

t=0 0

m=audio 3456 RTP/AVP 97 96

a=curr:qos local sendrcv

a=curr:qos remote sendrcv

a=des:qos mandatory local sendrecv

a=des:qos mandatory remote sendrecv

a=rtpmap:97 AMR

a=fmtp:97 mode-set=0,2,5,7; mode-change-period=2

a=maxptime:20

27-28. SIP ACK request (originating IM CN subsystem to SCC AS via intermediate IM CN subsystem entities and SCC AS)

The originating IM CN subsystem sends a SIP ACK request to the SCC AS via the intermediate IM CN subsystem entities. There is no ICS specific content in this response.