A.13 Signalling flows for session replication / media replication performed by the remote UE

24.3373GPPIP Multimedia (IM) Core Network (CN) subsystem IP Multimedia Subsystem (IMS) inter-UE transferRelease 17Stage 3TS

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

A.13.1 General

The signalling flows in the subclause demonstrate how session replication / media replication performed by remote UE can be applied on a session.

A.13.2 Signalling flows for session replication / media replication performed by the remote UE – pull mode

A.13.2.1 Introduction

The signalling flows in the subclause demonstrate how pull mode session replication / media replication performed by remote UE can be applied on a session.

A.13.2.2 Pull mode session replication

In the example flow at the figure A.13.2.2-1, UE-1 has an ongoing multimedia session with UE-3 anchored at SCC AS-1. The session is established using an IMS communication service identified by ICSI urn:urn-7:3gpp-service.ims.icsi.iptv. UE-1 and UE-2 belong to different subscribers. UE-3 is an application server acting as a terminating UE.

Figure A.13.2.2-1: Signalling flow for session replication in the remote UE – Pull mode

NOTE 1: For clarity, the SIP 100 (Trying) messages and SIP NOTIFY with SIP 100 (Trying) are not shown in the signalling flow.

1. UE-1 is in session with UE-3

There is a multimedia session comprising audio and video media between the UE-1 and the remote UE-3 anchored at SCC AS-1. The session was established using IMS communication service identified by ICSI urn:urn-7:3gpp-service.ims.icsi.iptv. The dialog identifier of the session between SCC AS-1 and UE-1 is AB03a0s09a2sdfglkj490333, remote-tag=dfg45, local-tag=444.

2. UE-2 decides to replicate the session of UE-1 to UE-2.

3. UE-2 fetches the dialog information of the UE-1 from SCC AS-1.

4-9. SIP REFER request (UE-2 to UE-1) – see example in table A.13.2.2-4

The UE-2 sends SIP REFER request to UE-1 to request the playback state. When SCC AS-1 forwards the SIP REFER request, the SCC AS-1 authorizes the request.

Table A.13.2.2-4: SIP REFER request

REFER sip:user1@home1.net;gr=urn:uuid:f81d4fae-7dec-11d0-1111-111111111111 SIP/2.0

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

Max-Forwards: 70

P-Preferred-Identity: <sip:user2@home1.net>

From: <sip:user2@home1.net>;tag=171828

To: <sip:user1@home1.net;gr=urn:uuid:f81d4fae-7dec-11d0-1111-111111111111>

Call-ID: ddfftq34gasgaegr

Cseq: 1112 REFER

Contact: <sip:user2@home1.net;gr=urn:uuid:f81d4fae-7dec-11d0-2222-222222222222>

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

Content-Type: application/vnd.3gpp.replication+xml

Content-Length: (…)

Supported: 100rel, precondition

Refer-To: <sip:user2@home1.net;gr=urn:uuid:f81d4fae-7dec-11d0-2222-222222222222;method=MESSAGE?In-Reply-To=ddfftq34gasgaegr>

Target-Dialog: AB03a0s09a2sdfglkj490333;remote-tag=dfg45;local-tag=444

Require: tdialog

<?xml version="1.0" encoding="UTF-8"?>

<ms:requestedParameters

xmlns:ms="urn:3gpp:ns:mediaState:1.0"

….

</ms:requestedParameters>

Request-URI: set to the URI of UE-1

Refer-To: contains the URI of UE-2 extended with the method parameter set to MESSAGE and with In-Reply-To URI header field containing the call-id of the SIP REFER request

Target-Dialog: contains the dialog identifier of the session being replicated

application/vnd.3gpp.replication+xml: lists the playback state parameters to be provided

NOTE 2: the playback state parameters are not shown

10-15. SIP 200 (OK) response for the SIP REFER request (UE-1 to UE-2)

16-21. SIP MESSAGE request (UE-1 to UE-2)

Based on the received SIP REFER request, the UE-2 generate a SIP MESSAGE request with values of the requested playback state parameters.

Table A.13.2.2-16: SIP MESSAGE request

MESSAGE sip:user2@home1.net;gr=urn:uuid:f81d4fae-7dec-11d0-2222-222222222222 SIP/2.0

Via: SIP/2.0/UDP [5555::aaa:bbb:ccc:32ff]:887;comp=sigcomp;branch=z9hG4bKnashds775

Max-Forwards: 70

P-Preferred-Identity: <sip:user1@home1.net>

From: <sip:user1@home1.net>;tag=aaa171828

To: <sip:user2@home1.net;gr=urn:uuid:f81d4fae-7dec-11d0-2222-222222222222>

Call-ID: dfsgaerddfftq34gasgaegr

Cseq: 41112 MESSAGE

Contact: <sip:user1@home1.net;gr=urn:uuid:f81d4fae-7dec-11d0-1111-111111111111>

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

Content-Type: application/vnd.3gpp.replication+xml

Content-Length: (…)

Supported: 100rel, precondition

In-Reply-To: ddfftq34gasgaegr

<?xml version="1.0" encoding="UTF-8"?>

<ms:parameterValues

xmlns:ms="urn:3gpp:ns:mediaState:1.0"

….

</ms:parameterValues>

Request-URI: set to the URI of UE-2

In-Reply-To: containing the value of the In-Reply-To URI header field of the Refer-To header field of the SIP REFER request

application/vnd.3gpp.replication+xml: lists the values of the requested playback state parameters

NOTE 3: the playback state parameters and their values are not shown

22-27. SIP 200 (OK) response to SIP MESSAGE request (UE-2 to UE-1)

The UE-2 confirms the SIP MESSAGE request by sending SIP 200 (OK) response to SIP MESSAGE request.

28-33. SIP NOTIFY request (UE-1 to UE-2)

The UE-1 informs the UE-2 that the action triggered by SIP REFER request was successfully completed.

34-39. SIP 200 (OK) response to SIP NOTIFY request (UE-2 to UE-1)

The UE-2 confirms the SIP NOTIFY request by sending SIP 200 (OK) response to SIP NOTIFY request.

40-44. SIP INVITE request (UE-2 to UE-3)

The UE-2 establishes a session with UE-3 using the remote URI provided in the dialog event package in the step 3.

45-49. SIP 200 (OK) response to SIP INVITE request (UE-3 to UE-2)

The UE-3 establishes the session by sending SIP 200 (OK) response to SIP INVITE request.

50-54. SIP ACK request (UE-2 to UE-3)

55. UE-2 sets up the playback state based on the playback state parameters received message 13.

56-57. Media path:

Two independent sessions exist – the original session still has the media path between UE-1 and UE-3 and the replicated session has the media path between UE-2 and UE-3.

A.13.3 Signalling flows for session replication / media replication performed by the remote UE – push mode

A.13.3.1 Introduction

The signalling flows in the subclause demonstrate how push mode session replication / media replication performed by remote UE can be applied on a session.

A.13.3.2 Push mode session replication

In the example flow at the figure A.13.3.2-1, UE-1 has an ongoing multimedia session with UE-3 anchored at SCC AS-1. UE-1 and UE-2 belong to different subscribers.

Editor’s Note (WID IMS_SC_eIDT): It is FFS if the session replication can be replication of some of the media components belonging to the session.

Figure A.13.3.2-1: Signalling flow for replication of session existing at other UE

NOTE 1: For clarity, the SIP 100 (Trying) responses and SIP NOTIFY requests with SIP 100 (Trying) are not shown in the signalling flow.

1. UE-1 is in session with UE-3

The dialog identifier of the session between SCC AS-1 and UE-1 is AB03a0s09a2sdfglkj490333, remote-tag=dfg45, local-tag=444.

2. UE-1 decides to replicate the session from UE-1 to UE-2.

3-9. SIP REFER request (UE-1 to UE-2) – see example in table A.13.3.2-3

The UE-1 sends SIP REFER request to UE-2 to request the session replication. When SCC AS-2 receives the SIP REFER request, the SCC AS-2 authorizes the request.

Table A.13.3.2-3: SIP REFER request (UE-1 to Intermediate IM CN subsystem entities)

REFER sip:user2@home1.net;gr=urn:uuid:f81d4fae-7dec-11d0-2222-222222222222 SIP/2.0

Via: SIP/2.0/UDP [5555::aaa:bbb:ccc:ddd]:1357;comp=sigcomp;branch=z9hG4bKnashds7dfdsdq

Max-Forwards: 70

P-Preferred-Identity: <sip:user1@home1.net>

From: <sip:user1@home1.net>;tag=171828

To: <sip:user2@home1.net;gr=urn:uuid:f81d4fae-7dec-11d0-2222-222222222222>

Call-ID: Asdasd23123366

Cseq: 41277 REFER

Contact: <sip:user1@home1.net;gr=urn:uuid:f81d4fae-7dec-11d0-1111-111111111111>

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

Content-Length: 0

Refer-To: <sip:user3@home2.net?P-Preferred-Service=urn:urn-7:3gpp-service.ims.icsi.iptv&Accept-Contact=*%3b+g.3gpp.icsi-ref%3d%22urn%253Aurn-7%253gpp-service.ims.icsi.iptv%22>

Referred-By: <sip:user1@home1.net>

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

Content-Type: application/vnd.3gpp.replication+xml

Content-Length: (…)

<?xml version="1.0" encoding="UTF-8"?>

<ms:replication>

<ms:parameterValues

xmlns:ms="urn:3gpp:ns:mediaState:1.0"

….

</ms:parameterValues>

</ms:replication>

Request-URI: contains the GRUU of the UE-2

Refer-To: contains the URI of UE-3 and IMS Communication Service of the existing session.

application/vnd.3gpp.replication+xml: indicates that push mode replication is requested and if available, lists the values of the playback state parameters

NOTE 2: the playback state parameters and their values are not shown

10-16. SIP 200 (OK) response for the SIP REFER request (UE-1 to UE-2)

17-21. SIP INVITE request (UE-2 to UE-3)

The UE-2 establishes a session with UE-3 based on the information provided in the SIP REFER request.

Table A.13.3.2-17: SIP INVITE request (UE-2 to UE-3)

INVITE sip:user3@home2.net SIP/2.0

Via: SIP/2.0/UDP 123.112.67.87:5454;comp=sigcomp;branch=z9hG4bKnashds7dfgdfsgr

To: sip:user3@home2.net

From: sip:user2@home1.net;tag=acegi

Call-ID: Asdasd2312336asa6

CSeq: 200 INVITE

Max-Forwards: 70

P-Preferred-Identity: sip:user2@home1.net

Contact: <sip:user2@home1.net;gr=urn:uuid:f81d4fae-7dec-11d0-2222-222222222222>;+g.3gpp.icsi-ref="urn%3Aurn-7%3gpp-service.ims.icsi.iptv"

P-Preferred-Service: urn:urn-7:3gpp-service.ims.icsi.iptv

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

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

Content-Type: application/sdp

Supported: 100rel, precondition, 199

v=0

o=- 1027933615 1027933615 IN IP4 123.112.67.87

s=-

t=0 0

m=audio 1456 RTP/AVP 96 0

c=IN IP4 123.112.67.87

22-26. SIP 200 (OK) response to SIP INVITE request (UE-3 to UE-2)

The UE-3 establishes the session by sending SIP 200 (OK) response to SIP INVITE request.

27-31. SIP ACK request (UE-2 to UE-3)

32-38. SIP NOTIFY request (UE-2 to UE-1)

The UE-2 informs the UE-1 that the action triggered by SIP REFER request was successfully completed.

39-45. SIP 200 (OK) response to SIP NOTIFY request (UE-1 to UE-2)

The UE-1 confirms the SIP NOTIFY request by sending SIP 200 (OK) response to SIP NOTIFY request.

46-47. Media

Two independent sessions exist – the original session still has the media path between UE-1 and UE-3 and the replicated session has the media path between UE-2 and UE-3.