A.3 CCNR activation

24.6423GPPCompletion of Communications to Busy Subscriber (CCBS) and Completion of Communications by No Reply (CCNR) using IP Multimedia (IM) Core Network (CN) subsystemProtocol specificationRelease 16TS

Figure A.3.1: CCNR activation

Figure A.3.1 shows a basic signalling flow for a CCNR activation.

Call flows

1 to 5: The communication is initiated by UE-A by sending an INVITE request. The Request-URI will include the URI of UE-B. After IFC evaluation in the S-CSCF the INVITE request is routed to the originating AS and after that to the terminating AS and further on to UE-B.

Table A.3-1: SIP INVITE request (UE to P-CSCF)

INVITE sip:user2_public2@home2.net SIP/2.0

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

Max-Forwards: 70

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

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: <sip:user2_public2@home2.net>

Call-ID: cb03a0s09a2sdfglkj490333

CSeq: 127 INVITE

Supported: 100rel; precondition, gruu, 199

Require: sec-agree; replaces

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

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 99

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=inactive

a=rtpmap:98 H263

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

a=rtpmap:99:MPVMP4V-ES

m=audio 3456 RTP/AVP 97 96

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=inactive

a=rtpmap:97 AMR

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

a=rtpmap:96 telephone-event

6: UE-B answers with a 180 (Ringing) response. The 180 (Ringing) response is routed back to the terminating AS.

7 to 8: The terminating AS inserts a Call-Info header field in the 180 (Ringing) response according to the procedures described in RFC 6910 [5]. The Call-Info header field will contain the URI of the terminating AS with an "m" header field parameter set to "NR" (no reply). It further includes a "purpose" header field parameter set to "call-completion". The 180 (Ringing) response is routed back to the originating AS.

Table A.3-2: 180 Ringing (Terminating AS to S-CSCF))

SIP/2.0 180 Ringing

Via: SIP/2.0/UDP tas.home2.net;branch= z9hG4bK332b23.1, SIP/2.0/UDP scscf2.home2.net;branch=z9hG4bK344a65.1, SIP/2.0/UDP icscf2_s.home2.net;branch=z9hG4bKj5hgrt2o, SIP/2.0/UDP scscf1.home1.net;branch=z9hG4bKehuehjgt, SIP/2.0/UDP oas.home1.net;branch=z9hG4bKnashds7, SIP/2.0/UDP pcscf1.visited1.net;branch=z9hG4bK240f34.1, [5555::aaa:bbb:ccc:ddd]:1357;comp=sigcomp;branch=z9hG4bKnashds7

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

To: <sip:user2_public2@home2.net>;tag=314159

Call-ID: cb03a0s09a2sdfglkj490333

CSeq: 127 INVITE

Retry-After: 3600

Contact: <sip:user2_public2@visited2.net;gr=urn:uuid:f81d4fae-7dec-11d0-a765-00a0c91ewxyz>;+g.3gpp.icsi-ref="urn%3Aurn-7%3gpp-service.ims.icsi.mmtel"

Content-Length: 0

Call-Info:<sip:tas.home2.net>;purpose=call-completion;m=NR

9 to 10: The originating AS removes the Call-Info header field, forwards the 180 (Ringing) response to UE-A and initiates IVR procedures. User A is informed that CCNR is possible. User A activates CCNR.

11 to 12: The originating AS subscribes for the call-completion event package according to the procedures described in RFC 6910 [5] at the terminating AS. The originating AS generates a SUBSCRIBE request which Request-URI will include the URI of the terminating AS. In order to mark the SUBSCRIBE request as a request for CCNR, the originating AS adds the "m" SIP URI parameter with the value "NR" to the Request-URI. The From header field will include the caller URI. The To header field will include the URI of UE-B.

Table A.3-3: SUBSCRIBE request (Originating AS to S-CSCF)

SUBSCRIBE sip:tas.home2.net;m=NR SIP/2.0

Via: SIP/2.0/UDP oas.home1.net;branch=z9hG4bKnashds7

Max-Forwards: 70

Route: <sip:scscf1.home1.net>

P-Asserted-Identity: <sip:user1_public1@home1.net>

From: <sip:user1_public1@home1.net>;tag=31415

To: <sip:user2_public2@home2.net>

Call-ID: b89rjhnedlrfjflslj40a222

CSeq: 61 SUBSCRIBE

Call-Info:<sip:user1_public1@home1.net>;purpose=call-completion;m=NR

Event: call-completion

Expires: 5400

Contact: <sip:oas.home1.net>

Content-Length: 0

13 to 14 The terminating AS accepts the subscription and starts supervision procedures on activity of the callee.

Table A.3-4: 200 (OK) response (Terminating AS to S-CSCF)

SIP/2.0 200 OK

Via: SIP/2.0/UDP scscf2.home2.net;branch=z9hG4bK344a65.1, SIP/2.0/UDP icscf2_s.home2.net;branch=z9hG4bKj5hgrt2o, SIP/2.0/UDP scscf1.home1.net;branch=z9hG4bKehuehjgt, SIP/2.0/UDP oas.home1.net;branch=z9hG4bKnashds7

Record-Route:

From:

To: <sip:user2_public2@home2.net>;tag=151170

Call-ID:

CSeq:

Event:

Expires: 5400

Contact: <sip:tas.home2.net>

Content-Length:

15 to 18: The terminating AS sends a notification to the originating AS, according to the procedures described in RFC 6910 [5]. The Request-URI of the NOTIFY request will include the URI of the originating AS. The body contains parameters informing of the caller’s call-completion state ‘queued’ and the availability of the call-completion service retention at the terminating AS. After confirmation of the notification the originating AS starts announcements procedures informing about the activation of CCNR.

Table A.3-5: NOTIFY request (Terminating AS to S-CSCF)

NOTIFY sip:oas.home1.net SIP/2.0

Via: SIP/2.0/UDP tas.home2.net;branch=z9hG4bK348923.1

Max-Forwards: 70

Route: <sip:scscf2.home2.net>

P-Asserted-Identity: <sip:tas.home2.net>

From: <sip:user2_public2@home2.net>;tag=151170

To: <sip:user1_public1@home1.net>;tag=31415

Call-ID: b89rjhnedlrfjflslj40a222

CSeq: 42 NOTIFY

Subscription-State: active ;expires=5399

Event: call-completion

Contact: <sip:tas.home2.net>

Content-Type: application/call-completion

Content-Length: (…)

cc-state: queued

cc-service retention

19 to 28: UE-A initiates the termination of the session setup by sending a CANCEL request to UE-B.

29 to 38: UE-B terminates the session setup by sending a 487 Request terminated to UE-A.