A.5.3 CAT when UE#1 does not have required resources available while UE#2 has resources available

24.1823GPPIP Multimedia Subsystem (IMS) Customized Alerting Tones (CAT)Protocol specificationRelease 17TS

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

Figure A.5.3-1 shows an example call flow for CAT when UE#1 does not have required resources available and UE#2 have resources available.

Figure A.5.3-1: CAT, UE#1 does not have required resources available

1 INVITE request (UE#1 to CAT-AS) see example in table A.5.3-1

UE#1 sends a SIP INVITE request to the intermediate IM CN subsystem.

Table A.5.3-1: INVITE request (UE#1 to CAT-AS)

INVITE tel:+1-212-555-2222 SIP/2.0

Via: SIP/2.0/UDP [5555::aaa:bbb:ccc:ddd]:1357;comp=sigcomp;branch=z9hG4bKnashds7

Max-Forwards: 70

Route: <sip:pcscf1.visited1.net:7531;lr;comp=sigcomp>, <sip:scscf1.home1.net;lr>

P-Preferred-Identity: "John Doe" <sip:user1_public1@home1.net>

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

P-Preferred-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

P-Early-Media: supported

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

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

Call-ID: cb03a0s09a2sdfglkj490333

Cseq: 127 INVITE

Require: sec-agree

Recv-Info: infoDtmf

Supported: precondition, 100rel, gruu, 199

Proxy-Require: sec-agree

Security-Verify: ipsec-3gpp; q=0.1; alg=hmac-sha-1-96; spi-c=98765432; spi-s=87654321; port-c=8642; port-s=7531

Contact: <sip:user1_public1@home1.net;gr=urn:uuid:f81d4fae-7dec-11d0-a765-00a0c91e6bf6 >;+g.3gpp.icsi-ref="urn%3Aurn-7%3gpp-service.ims.icsi.mmtel"

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

Accept:application/sdp, application/3gpp-ims+xml

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=video 3400 RTP/AVP 98

a=tcap:1 RTP/AVPF

a=pcfg:1 t=1

b=AS:75

a=curr:qos local none

a=curr:qos remote none

a=des:qos mandatory local sendrecv

a=des:qos none remote sendrecv

a=rtpmap:98 H263

a=fmtp:98 profile-level-id=0

m=audio 3456 RTP/AVP 97 96

a=tcap:1 RTP/AVPF

a=pcfg:1 t=1

b=AS:25.4

a=curr:qos local none

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; maxframes=2

a=rtpmap:96 telephone-event

Supported: The UE indicates support for GRUU, 199 responses, reliable provisional responses and preconditions.

P-Early-Media: The UE indicates support for the P-Early-Media header.

Recv-Info: The UE indicates willingness to receive DTMF Info Packages in INFO requests.

SDP The SDP offer (SDP_O) contains a set of codecs supported by UE#1 and desired by the calling user for this session. The local preconditions are indicated as not fulfilled.

2 INVITE request (S-CSCF to CAT-AS)

The S-CSCF forwards the SIP INVITE request to the CAT-AS.

The CAT-AS instructs the MRF to reserve CAT resources.

3-4 INVITE request (CAT-AS to UE#2)

The CAT-AS forwards the request to UE#2.

5-6 183 (Session Progress) provisional response (UE#2 to CAT-AS) see example in table A.5.3-2

UE#2 sends a reliable SIP 183 (Session Progress) provisional response for the INVITE request to the CAT-AS.

The CAT-AS terminates the provisional response.

Table A.5.3-2: 183 (Session Progress) provisional response (UE#2 to CAT-AS)

SIP/2.0 183 Session Progress

Via: SIP/2.0/UDP pcscf2.visited2.net:5088;comp=sigcomp;branch=z9hG4bK361k21.1, SIP/2.0/UDP scscf2.home2.net;branch=z9hG4bK764XC12.1, SIP/2.0/UDP catas.home2.net;branch=z9hG4bK764Q32.1, SIP/2.0/UDP scscf2.home2.net;branch=z9hG4bK764z87.1, SIP/2.0/UDP icscf2_s.home2.net;branch=z9hG4bK871y12.1, SIP/2.0/UDP scscf1.home1.net;branch=z9hG4bK332b23.1, SIP/2.0/UDP pcscf1.visited1.net;branch=z9hG4bK240f34.1, SIP/2.0/UDP [5555::aaa:bbb:ccc:ddd]:1357;comp=sigcomp;branch=z9hG4bKnashds7

Record-Route: <sip:pcscf2.visited2.net:5088;lr;comp=sigcomp>, <sip:scscf2.home2.net;lr>, <sip:catas.home2.net;lr>, <sip:scscf2.home2.net;lr>, <sip:scscf1.home1.net;lr>, <sip:pcscf1.visited1.net;lr>

From:

To: <tel:+1-212-555-2222>;tag=2236

Call-ID:

Cseq:

Require: 100rel

RSeq: 9022

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

Contact: <sip:user2_public1@home2.net;gr=urn:uuid:2ad8950e-48a5-4a74-8d99-ad76cc7fc74>;+g.3gpp.icsi-ref="urn%3Aurn-7%3gpp-service.ims.icsi.mmtel"

Content-Type: application/sdp

Content-Length: (…)

v=0

o=- 29879336157 29879336157 IN IP6 6666::eee:fff:aaa:bbb

s=-

c=IN IP6 6666::eee:fff:aaa:bbb

t=0 0

m=video 7398 RTP/AVPF 98

a=acfg:1 t=1

b=AS:75

a=curr:qos local sendrecv

a=curr:qos remote none

a=des:qos mandatory local sendrecv

a=des:qos mandatory remote sendrecv

a=rtpmap:98 H263

a=fmtp:98 profile-level-id=0

m=audio 8386 RTP/AVPF 97 96

a=acfg:1 t=1

b=AS:25.4

a=curr:qos local sendrecv

a=curr:qos remote none

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; maxframes

a=rtpmap:96 telephone-event

SDP The SDP answer (SDP_A_regular) contains a set of codecs to be used for the session. The local preconditions are indicated as not fulfilled.

7-8 183 (Session Progress) provisional response (CAT-AS to UE#1) see example in table A.5.3-3

The CAT-AS sends a reliable SIP 183 (Session Progress) provisional response to UE#1. The CAT-AS shall take into account, when creating the SDP message, the media indicated by UE#2 in the previously received 183 (Session Progress) provisional response and the one used by MRF for the media for CAT.

Table A.5.3-3: 183 (Session Progress) response (CAT-AS to UE#1)

SIP/2.0 183 Session Progress

Via: SIP/2.0/UDP scscf2.home2.net;branch=z9hG4bK764z87.1, SIP/2.0/UDP icscf2_s.home2.net;branch=z9hG4bK871y12.1, SIP/2.0/UDP scscf1.home1.net;branch=z9hG4bK332b23.1, SIP/2.0/UDP pcscf1.visited1.net;branch=z9hG4bK240f34.1, SIP/2.0/UDP [5555::aaa:bbb:ccc:ddd]:1357;comp=sigcomp;branch=z9hG4bKnashds7

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

From:

To: <tel:+1-212-555-2222>;tag=2236

Call-ID:

Cseq:

Require: 100rel

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

RSeq: 9022

P-Early-Media: sendrecv

Contact: <sip:catas.home2.net>;+g.3gpp.icsi-ref="urn%3Aurn-7%3gpp-service.ims.icsi.mmtel"

Content-Type: application/sdp

Content-Length: (…)

v=0

o=- 29879336156 29879336156 IN IP6 5555::ccc:aaa:abc:abc

s=-

c=IN IP6 5555::ccc:aaa:abc:abc

t=0 0

m=video 51372 RTP/AVPF 98

a=acfg:1 t=1

b=AS:75

a=curr:qos local sendrecv

a=curr:qos remote none

a=des:qos mandatory local sendrecv

a=des:qos mandatory remote sendrecv

a=rtpmap:98 H263

a=fmtp:98 profile-level-id=0

a=content:g.3gpp.cat

m=audio 49170 RTP/AVPF 97 96

a=acfg:1 t=1

b=AS:25.4

a=curr:qos local sendrecv

a=curr:qos remote none

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; maxframes

a=rtpmap:96 telephone-event

a=content:g.3gpp.cat

P-Early-Media: The CAT-AS requests authorization for early media.

SDP The SDP answer (SDP_A_cat) contains a set of codecs supported to be used for CAT and, in this example, includes a SDP "a=content" attribute with a "g.3gpp.cat" value for each media description. The SDP content is based on information received from the MRF and information in the previously received 183 (Session Progress) provisional response from UE#2. The local preconditions are indicated as not fulfilled.

9-12 PRACK request (UE#1 to CAT-AS, and to UE#2)

UE#1 sends a SIP PRACK request, which acknowledges the SIP 183 (Session Progress) provisional response, to the CAT-AS, which is further sent to UE#2.

13-16 200 (OK) response to PRACK request (UE#2 to CAT-AS, and to UE#1)

UE#2 sends a SIP 200 (OK) response for the SIP PRACK request to CAT-AS, which is further sent to UE#1.

17-18 UPDATE request (UE#1 to CAT-AS) – see example in table A.5.3-4

UE#1 indicates that it can send and receive media as the necessary resources are available.

Table A.5.3-4: UPDATE request (UE#1 to CAT-AS)

UPDATE sip:user2_public1@home2.net;gr=urn:uuid:2ad8950e-48a5-4a74-8d99-ad76cc7fc74 SIP/2.0

Via: SIP/2.0/UDP [5555::aaa:bbb:ccc:ddd]:1357;comp=sigcomp;branch=z9hG4bKnashds7

Max-Forwards: 70

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

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

To: <tel:+1-212-555-2222>;tag=2236

Call-ID:

Cseq: 129 UPDATE

Require: sec-agree

Proxy-Require: sec-agree

Security-Verify: ipsec-3gpp; q=0.1; alg=hmac-sha-1-96; ealg=aes-cbc; spi-c=98765432; spi-s=87654321; port-c=8642; port-s=7531

Contact: <sip:user1_public1@home1.net;gr=urn:uuid:f81d4fae-7dec-11d0-a765-00a0c91e6bf6>;+g.3gpp.icsi-ref="urn%3Aurn-7%3gpp-service.ims.icsi.mmtel"

Content-Type: application/sdp

Content-Length: (…)

v=0

o=- 2987933615 2987933616 IN IP6 5555::aaa:bbb:ccc:ddd

s=-

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

t=0 0

m=video 3400 RTP/AVPF 98

b=AS:75

a=curr:qos local sendrecv

a=curr:qos remote sendrecv

a=des:qos mandatory local sendrecv

a=des:qos none remote sendrecv

a=rtpmap:98 H263

a=fmtp:98 profile-level-id=0

m=audio 3456 RTP/AVPF 97 96

b=AS:25.4

a=curr:qos local sendrecv

a=curr:qos remote sendrecv

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; maxframes=2

a=rtpmap:96 telephone-event

SDP The SDP offer (SDP_O_cat) contains a set of codecs supported to be used for CAT. The SDP content is based on information received from the MRF. The local preconditions are indicated as fulfilled.

19-20 UPDATE request (CAT-AS to UE#2) – see example in table A.5.3-5

CAT-AS indicates to UE#2 that UE#1 can send and receive media as the necessary resources are available.

Table A.5.3-5: UPDATE request (CAT-AS to UE#2)

UPDATE sip:user2_public1@home2.net;gr=urn:uuid:2ad8950e-48a5-4a74-8d99-ad76cc7fc74;comp=sigcomp SIP/2.0

Max-Forwards: 66

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

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

To: <tel:+1-212-555-2222>;tag=2236

Call-ID:

Cseq: 56101 UPDATE

Require: sec-agree

Proxy-Require: sec-agree

Security-Verify: ipsec-3gpp; q=0.1; alg=hmac-sha-1-96; ealg=aes-cbc; spi-c=98765432; spi-s=87654321; port-c=8642; port-s=7531

Contact: <sip:user1_public1@home1.net;gr=urn:uuid:f81d4fae-7dec-11d0-a765-00a0c91e6bf6>;+g.3gpp.icsi-ref="urn%3Aurn-7%3gpp-service.ims.icsi.mmtel"

Content-Type: application/sdp

Content-Length: (…)

v=0

o=- 2987933615 2987933615 IN IP6 5555::ccc:aaa:abc:abc

s=-

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

t=0 0

m=video 3400 RTP/AVPF 98

b=AS:75

a=curr:qos local sendrecv

a=curr:qos remote sendrecv

a=des:qos mandatory local sendrecv

a=des:qos none remote sendrecv

a=rtpmap:98 H263

a=fmtp:98 profile-level-id=0

m=audio 3456 RTP/AVPF 97 96

b=AS:25.4

a=curr:qos local sendrecv

a=curr:qos remote sendrecv

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; maxframes=2

a=rtpmap:96 telephone-event

SDP The SDP offer (SDP_O_regular) contains a set of codecs supported to be used for regular conversation. The local preconditions are indicated as fulfilled.

21-22 200 (OK) response (UE#2 to CAT-AS) – see example in table A.5.3-6

UE#2 sends a SIP 200 (OK) response for the SIP UPDATE request to CAT-AS. The SDP shall contain information relevant to the media that will be used after the session is established.

CAT-AS shall store the relevant information in SDP for later use in step 31.

Table A.5.3-6: 200 (OK) response (UE#2 to CAT-AS)

SIP/2.0 200 OK

Record-Route: <sip:pcscf2.visited2.net:5088;lr;comp=sigcomp>, <sip:scscf2.home2.net;lr>, <sip:catas.home2.net;lr>, <sip:scscf2.home2.net;lr>, <sip:scscf1.home1.net;lr>, <sip:pcscf1.visited1.net;lr>

From:

To: <tel:+1-212-555-2222>;tag=2236

Call-ID:

Cseq:

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

Contact: <sip:user2_public1@home2.net;gr=urn:uuid:2ad8950e-48a5-4a74-8d99-ad76cc7fc74>;+g.3gpp.icsi-ref="urn%3Aurn-7%3gpp-service.ims.icsi.mmtel"

Content-Type: application/sdp

Content-Length: (…)

v=0

o=- 29879336157 29879336157 IN IP6 6666::eee:fff:aaa:bbb

s=-

c=IN IP6 6666::eee:fff:aaa:bbb

t=0 0

m=video 7398 RTP/AVPF 98

b=AS:75

a=curr:qos local sendrecv

a=curr:qos remote sendrecv

a=des:qos mandatory local sendrecv

a=des:qos mandatory remote sendrecv

a=rtpmap:98 H263

a=fmtp:98 profile-level-id=0

m=audio 8386 RTP/AVPF 97 96

b=AS:25.4

a=curr:qos local sendrecv

a=curr:qos remote sendrecv

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; maxframes

a=rtpmap:96 telephone-event

SDP The SDP answer (SDP_A_regular) contains a set of codecs to be used for the session. The local preconditions are indicated as fulfilled.

23-24 200 (OK) response (CAT-AS to UE#1) – see example in table A.5.3-7

CAT-AS sends a SIP 200 (OK) response for the SIP UPDATE request to UE#1. The SDP shall contain information relevant to the media for CAT used by the MRF.

Table A.5.3-7: 200 (OK) response (CAT-AS to UE#1)

SIP/2.0 200 OK

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

From:

To: <tel:+1-212-555-2222>;tag=2236

Call-ID:

Cseq:

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

Contact: <sip:catas.home2.net>;+g.3gpp.icsi-ref="urn%3Aurn-7%3gpp-service.ims.icsi.mmtel"

Content-Type: application/sdp

Content-Length: (…)

v=0

o=- 29879336156 29879336157 IN IP6 5555::ccc:aaa:abc:abc

s=-

c=IN IP6 555::ccc:aaa:abc:abc

t=0 0

m=video 7398 RTP/AVPF 98

b=AS:75

a=curr:qos local sendrecv

a=curr:qos remote sendrecv

a=des:qos mandatory local sendrecv

a=des:qos mandatory remote sendrecv

a=rtpmap:98 H263

a=fmtp:98 profile-level-id=0

m=audio 8386 RTP/AVPF 97 96

b=AS:25.4

a=curr:qos local sendrecv

a=curr:qos remote sendrecv

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; maxframes

a=rtpmap:96 telephone-event

SDP The SDP answer (SDP_A_cat) contains a set of codecs to be used for CAT. The local preconditions are indicated as fulfilled.

25-26 180 (Ringing) provisional response (UE#2 to CAT-AS)

UE#2 sends a SIP 180 (Ringing) provisional response for the INVITE request to the CAT-AS.

The CAT-AS instructs the MRF to play CAT media upon receipt of 180.

27-28 180 (Ringing) provisional response (CAT-AS to UE#1)

CAT-AS sends a SIP 180 (Ringing) provisional response for the INVITE request to the UE#1.

29-30 200 (OK) response to INVITE request (UE#2 to CAT-AS)

The called party answers the call. UE#2 sends a SIP 200 (OK) final response for the SIP INVITE request to the CAT-AS.

The CAT-AS instructs the MRF to stop CAT media.

31-32 UPDATE request (CAT-AS to UE#1) see example in table A.5.3-8

The CAT-AS sends an UPDATE request containing values received in the 200 (OK) for UPDATE request from UE#2 in step 22.

Session between UE#1 and CAT-AS is replaced with session between UE#1 and UE#2.

NOTE 1: The AS will remain in the signalling path, i.e. work as a B2BUA, in order to align and maintain information in SDP for further exchanged messages between UE#1 and UE#2.

Table A.5.3-8: UPDATE request (CAT-AS to UE#1)

UPDATE sip:user1_public1@home1.net;gr=urn:uuid:f81d4fae-7dec-11d0-a765-00a0c91e6bf6 SIP/2.0

Via: SIP/2.0/UDP [5555::ccc:aaa:abc:abc]:8805;branch=z9hG4bK182D87.1

Max-Forwards: 70

Route: <sip:scscf1.home1.net;lr>, <sip:pcscf1.visited1.net;lr>

From: <tel:+1-212-555-2222>;tag=2236

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

Call-ID:

Cseq: 12814111 UPDATE

Require:

Contact: <sip:user2_public1@home2.net;gr=urn:uuid:2ad8950e-48a5-4a74-8d99-ad76cc7fc74>+g.3gpp.icsi-ref="urn%3Aurn-7%3gpp-service.ims.icsi.mmtel"

Content-Type: application/sdp

Content-Length: (…)

v=0

o=- 29879336156 29879336158 IN IP6 5555::ccc:aaa:abc:abc

s=-

c=IN IP6 6666::eee:fff:aaa:bbb

t=0 0

m=video 7398 RTP/AVPF 98

b=AS:75

a=curr:qos local sendrecv

a=curr:qos remote sendrecv

a=des:qos mandatory local sendrecv

a=des:qos mandatory remote sendrecv

a=rtpmap:98 H263

a=fmtp:98 profile-level-id=0

m=audio 8386 RTP/AVPF 97 96

b=AS:25.4

a=curr:qos local sendrecv

a=curr:qos remote sendrecv

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; maxframes

a=rtpmap:96 telephone-event

SDP The SDP offer (SDP_A_regular) contains a set of codecs to be used for the session. The SDP content is based on information received from previous 200 (OK) response.

33-34 200 (OK) response (UE#1 to CAT-AS)

UE#1 sends a SIP 200 (OK) response for the SIP UPDATE request to CAT-AS. If the resources indicated for the media cannot be reused by the one reserved for the CAT media, UE#1 shall reserve necessary resources prior to sending the response.UE#1 includes a SDP answer (SDP_O2) in the 200 (OK) response to the corresponding SIP UPDATE request.

35-36 200 (OK) response to INVITE request (CAT-AS to UE#1)

The CAT-AS sends the SIP 200 (OK) response for the (initial) SIP INVITE request to UE#1.

37-38 ACK request (UE#1 to CAT-AS)

UE#1 sends a SIP ACK request, which acknowledges the SIP 200 (OK) final response, to CAT-AS.

39-40 ACK request (CAT-AS to UE#2)

CAT-AS sends a SIP ACK request, which acknowledges the SIP 200 (OK) final response, to UE#2.

NOTE 3: The ACK request from CAT-AS towards UE#2 may be sent after receiving 200 (OK) from UE#2 in step 18.