Internet Engineering Task Force (IETF) R. Ravindranath

Internet Engineering Task Force (IETF) R. Ravindranath
Request for Comments: 8068 Cisco Systems, Inc.
Category: Informational P. Ravindran
ISSN: 2070-1721 Nokia Networks
P. Kyzivat
Huawei
February 2017

Session Initiation Protocol (SIP) Recording Call Flows

Abstract

Session recording is a critical requirement in many communications
environments, such as call centers and financial trading
organizations. In some of these environments, all calls must be
recorded for regulatory, compliance, and consumer-protection reasons.
The recording of a session is typically performed by sending a copy
of a media stream to a recording device. This document lists call
flows with metadata snapshots sent from a Session Recording Client
(SRC) to a Session Recording Server (SRS).

Status of This Memo

This document is not an Internet Standards Track specification; it is
published for informational purposes.

This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see Section 2 of RFC 7841.

Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc8068.

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RFC 8068 SIP Recording Call Flows February 2017

Copyright Notice

Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved.

This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.

Table of Contents

1. Overview ........................................................3
2. Terminology .....................................................3
3. Metadata XML Instances ..........................................3
3.1. Sample Call Flow ...........................................3
3.2. Call Scenarios with SRC Recording Streams without Mixing ...5
3.2.1. Example 1: Basic Call ...............................5
3.2.2. Example 2: Hold/Resume ..............................9
3.2.3. Example 3:Call Transfer (RE-INVITE and
REFER Based) .......................................12
3.2.4. Example 4: Call Disconnect .........................19
3.3. Call Scenarios with SRC Recording Streams by Mixing .......20
3.3.1. Example 1: Basic Call with SRC Mixing Streams ......20
3.3.2. Example 2: Hold/Resume with SRC Recording
by Mixing Streams ..................................23
3.3.3. Example 3: Metadata Snapshot of
Joining/Dropping of a ..............................25
3.3.4. Example 4: Call Disconnect .........................28
3.4. Call Scenarios with Persistent RS between SRC and SRS .....28
3.4.1. Example 1: Metadata Snapshot during CS
Disconnect with ....................................29
3.5. Turret-Case: Multiple CS into Single RS with Mixed
Stream ....................................................30
4. Security Considerations ........................................32
5. IANA Considerations ............................................32
6. References .....................................................33
6.1. Normative References ......................................33
6.2. Informative References ....................................33
Acknowledgements ..................................................34
Authors' Addresses ................................................34

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RFC 8068 SIP Recording Call Flows February 2017

1. Overview

Session recording is a critical requirement in many communications
environments, such as call centers and financial trading
organizations. In some of these environments, all calls must be
recorded for regulatory, compliance, and consumer-protection reasons.
The recording of a session is typically performed by sending a copy
of a media stream to a recording device. [RFC7865] focuses on the
recording metadata that describes the Communication Session (CS).
This document lists few examples and shows the snapshots of metadata
sent from a Session Recording Client (SRC) to Session Recording
Server (SRS). For the sake of simplicity, the entire Session
Initiation Protocol (SIP) [RFC3261] messages are not shown, instead
only snippets of the SIP and Session Description Protocol (SDP)
[RFC4566] messages and the XML snapshot of metadata is shown.

2. Terminology

The terms used in this document are defined in [RFC7865] and
[RFC6341]. No new definitions are introduced in this document.

3. Metadata XML Instances

The following subsections have examples that contain the metadata
snapshot sent from the SRC to the SRS.

3.1. Sample Call Flow

The following is a sample call flow that shows the SRC establishing a
Recording Session (RS) towards the SRS. In this example, the SRC
could be part of any one of the architectures described in Section 3
of [RFC7245].

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RFC 8068 SIP Recording Call Flows February 2017

Figure 1: Sample Call Flow between SRC and SRS

SRC SRS
| |
|(1) INVITE (metadata snapshot) F1 |
|---------------------------------------------------->|
| 200 OK |
|<----------------------------------------------------|
|(3) ACK |
|---------------------------------------------------->|
|(4) RTP |
|====================================================>|
|====================================================>|
|====================================================>|
|====================================================>|
|(5) UPDATE/RE-INVITE (metadata update 1) F2 |
|---------------------------------------------------->|
| 200 OK |
|<----------------------------------------------------|
| ................................................... |
| ................................................... |
| |
|====================================================>|
|====================================================>|
|(7) UPDATE/RE-INVITE (metadata update n-1) Fn-1 |
|---------------------------------------------------->|
| 200 OK |
|<----------------------------------------------------|

For the sake of simplicity, ACKs to RE-INVITES and BYEs are not
shown. The subsequent sections describe the snapshot of metadata
sent from the SRC to the SRS for each of the above transactions (F1
... Fn-1). There may be multiple UPDATES/RE-INVITES mid call to
indicate snapshots of different CS changes. Depending on the
architecture described in Section 3 of [RFC7245], an SRC may be an
endpoint, a B2BUA, or part of the MEDIACTRL architecture or the
Conference focus. The subsequent sections in this document try to
list some example metadata snapshots for three major categories.

o The SRC recording streams unmixed to the SRS. This includes cases
where the SRC is a SIP UA or B2BUA.

o The SRC recording mixed streams to the SRS. This includes cases
where the SRC is part of SIP conference model, as explained in
[RFC4353].

o The SRC having a persistent RS with the SRS.

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RFC 8068 SIP Recording Call Flows February 2017

o Special flows like turret flows (used on financial trading floors
to manage call activity). A trading turret is a specialized
telephony key system that has a highly distributed switching
architecture enabling parallel processing of calls. Figure 6 in
Section 4 of [RFC6341] has the turret use case.

Note that only those examples where metadata changes are listed in
each category. For some of the call flows, the snapshots may be the
same (like in case of endpoint or B2BUA acting as SRC) and the same
is mentioned in the text preceding the example.

3.2. Call Scenarios with SRC Recording Streams without Mixing

This section describes example flows where SRC can be a SIP-UA or
B2BUA as described in Section 3 of [RFC7245]. The SRS here can be a
SIP-UA or an entity part of the MEDIACTRL architecture described in
Section 3 of [RFC7245].

3.2.1. Example 1: Basic Call

Basic call between two participants, Alice and Bob, who are part of
the same CS. In this use case, each participant sends two media
streams (audio and video). Media streams sent by each participant
are received by the other participant in this use case. In this
example, the SRC is a B2BUA in the path between Alice and Bob, as
described in Section 3.1.1 of [RFC7245]. Below is the initial
snapshot sent by SRC in the INVITE to SRS. This snapshot has the
complete metadata. For the sake of simplicity, only snippets of SIP/
SDP are shown. In this example, the SRCs records the streams of each
participant to SRS without mixing.

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Metadata snapshot for CS setup:

INVITE SRC --------------> SRS

INVITE sip:[email protected] SIP/2.0
Via: SIP/2.0/TCP src.example.com;branch=z9hG4bKdf6b622b648d9
From: <sip:[email protected]>;tag=35e195d2-947d-4585-946f-09839247
To: <sip:[email protected]>
Call-ID: d253c800-b0d1ea39-4a7dd-3f0e20a
Session-ID: ab30317f1a784dc48ff824d0d3715d86
;remote=00000000000000000000000000000000
CSeq: 101 INVITE
Max-Forwards: 70
Require: siprec
Accept: application/sdp, application/rs-metadata,
application/rs-metadata-request
Contact: <sip:[email protected]>;+sip.src
Content-Type: multipart/mixed;boundary=foobar
Content-Length: [length]

--foobar
Content-Type: application/SDP
...
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=label:96
a=sendonly
...
m=video 49174 RTP/AVPF 96
a=rtpmap:96 H.264/90000
a=label:97
a=sendonly
...
m=audio 51372 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=label:98
a=sendonly
...
m=video 49176 RTP/AVPF 96
a=rtpmap:96 H.264/90000
a=label:99
a=sendonly
....
--foobar
Content-Type: application/rs-metadata
Content-Disposition: recording-session

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<?xml version="1.0" encoding="UTF-8"?>
<recording xmlns='urn:ietf:params:xml:ns:recording:1'>
<datamode>complete</datamode>
<group group_id="7+OTCyoxTmqmqyA/1weDAg==">
<associate-time>2010-12-16T23:41:07Z</associate-time>

<call-center xmlns='urn:ietf:params:xml:ns:callcenter'>
<supervisor>sip:[email protected]</supervisor>
</call-center>
<mydata xmlns='http://example.com/my'>
<structure>FOO!</structure>
<whatever>bar</whatever>
</mydata>
</group>
<session session_id="hVpd7YQgRW2nD22h7q60JQ==">
<sipSessionID>ab30317f1a784dc48ff824d0d3715d86;
remote=47755a9de7794ba387653f2099600ef2</sipSessionID>
<group-ref>7+OTCyoxTmqmqyA/1weDAg==
</group-ref>

<mydata xmlns='http://example.com/my'>
<structure>FOO!</structure>
<whatever>bar</whatever>
</mydata>
</session>
<participant
participant_id="srfBElmCRp2QB23b7Mpk0w==">
<nameID aor="sip:[email protected]">
<name xml:lang="it">Alice</name>
</nameID>

<mydata xmlns='http://example.com/my'>
<structure>FOO!</structure>
<whatever>bar</whatever>
</mydata>
</participant>
<participant
participant_id="zSfPoSvdSDCmU3A3TRDxAw==">
<nameID aor="sip:[email protected]">
<name xml:lang="it">Bob</name>
</nameID>

<mydata xmlns='http://example.com/my'>
<structure>FOO!</structure>
<whatever>bar</whatever>
</mydata>
</participant>

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<stream stream_id="UAAMm5GRQKSCMVvLyl4rFw=="
session_id="hVpd7YQgRW2nD22h7q60JQ==">
<label>96</label>
</stream>
<stream stream_id="i1Pz3to5hGk8fuXl+PbwCw=="
session_id="hVpd7YQgRW2nD22h7q60JQ==">
<label>97</label>
</stream>
<stream stream_id="8zc6e0lYTlWIINA6GR+3ag=="
session_id="hVpd7YQgRW2nD22h7q60JQ==">
<label>98</label>
</stream>
<stream stream_id="EiXGlc+4TruqqoDaNE76ag=="
session_id="hVpd7YQgRW2nD22h7q60JQ==">
<label>99</label>
</stream>
<sessionrecordingassoc session_id="hVpd7YQgRW2nD22h7q60JQ==">
<associate-time>2010-12-16T23:41:07Z</associate-time>
</sessionrecordingassoc>
<participantsessionassoc
participant_id="srfBElmCRp2QB23b7Mpk0w=="
session_id="hVpd7YQgRW2nD22h7q60JQ==">
<associate-time>2010-12-16T23:41:07Z</associate-time>
</participantsessionassoc>
<participantsessionassoc
participant_id="zSfPoSvdSDCmU3A3TRDxAw=="
session_id="hVpd7YQgRW2nD22h7q60JQ==">
<associate-time>2010-12-16T23:41:07Z</associate-time>
</participantsessionassoc>
<participantstreamassoc
participant_id="srfBElmCRp2QB23b7Mpk0w==">
<send>i1Pz3to5hGk8fuXl+PbwCw==</send>
<send>UAAMm5GRQKSCMVvLyl4rFw==</send>
<recv>8zc6e0lYTlWIINA6GR+3ag==</recv>
<recv>EiXGlc+4TruqqoDaNE76ag==</recv>
</participantstreamassoc>
<participantstreamassoc
participant_id="zSfPoSvdSDCmU3A3TRDxAw==">
<send>8zc6e0lYTlWIINA6GR+3ag==</send>
<send>EiXGlc+4TruqqoDaNE76ag==</send>
<recv>UAAMm5GRQKSCMVvLyl4rFw==</recv>
<recv>i1Pz3to5hGk8fuXl+PbwCw==</recv>
</participantstreamassoc>
</recording>

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RFC 8068 SIP Recording Call Flows February 2017

3.2.2. Example 2: Hold/Resume

A call between two participants Alice and Bob is established and an
RS is created for recording, as in example 1. Bob puts Alice on hold
and then resumes as part of the same CS. The 'send' and 'recv' XML
elements of a 'participantstreamassoc' XML element is used to
indicate whether or not a participant is contributing to a media
stream. SRC sends a snapshot with only the changed XML elements.

During hold

Metadata snapshot for CS hold:

RE-INVITE SRC-------------------->SRS

INVITE sip:[email protected] SIP/2.0
Via: SIP/2.0/TCP src.example.com;branch=z9hG4bKdf6b622b648d9
From: <sip:[email protected]>;tag=35e195d2-947d-4585-946f-09839247
To: <sip:[email protected]>
Call-ID: d253c800-b0d1ea39-4a7dd-3f0e20a
Session-ID: ab30317f1a784dc48ff824d0d3715d86
;remote=f81d4fae7dec11d0a76500a0c91e6bf6
CSeq: 101 INVITE
Max-Forwards: 70
Require: siprec
Accept: application/sdp, application/rs-metadata,
application/rs-metadata-request
Contact: <sip:[email protected]>;+sip.src
Content-Type: multipart/mixed;boundary=foobar
Content-Length: [length]

--foobar
Content-Type: application/SDP
...
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=label:96
a=sendonly
...
m=video 49174 RTP/AVPF 96
a=rtpmap:96 H.264/90000
a=label:97
a=sendonly
...
m=audio 51372 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=label:98
a=sendonly

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...
m=video 49176 RTP/AVPF 96
a=rtpmap:96 H.264/90000
a=label:99
a=sendonly
....

--foobar
Content-Type: application/rs-metadata
Content-Disposition: recording-session

<?xml version="1.0" encoding="UTF-8"?>
<recording xmlns='urn:ietf:params:xml:ns:recording:1'>
<datamode>partial</datamode>
<participantstreamassoc
participant_id="srfBElmCRp2QB23b7Mpk0w==">
<recv>8zc6e0lYTlWIINA6GR+3ag==</recv>
<recv>EiXGlc+4TruqqoDaNE76ag==</recv>
</participantstreamassoc>
<participantstreamassoc
participant_id="zSfPoSvdSDCmU3A3TRDxAw==">
<send>8zc6e0lYTlWIINA6GR+3ag==</send>
<send>EiXGlc+4TruqqoDaNE76ag==</send>
</participantstreamassoc>
</recording>

In the above snippet, Alice with participant_id
srfBElmCRp2QB23b7Mpk0w== only receives media streams and does not
send any media. The same is indicated by the absence of a 'send' XML
element. On the other hand, Bob (participant_id
zSfPoSvdSDCmU3A3TRDxAw==) would be sending media, but he does not
receive any media from Alice; therefore, the 'recv' XML element is
absent in this instance.

During resume

The snapshot now has 'send' and 'recv' XML elements for both Alice
and Bob, indicating that both are receiving and sending media.

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Metadata snapshot for CS resume:

RE-INVITE SRC-------------------->SRS

INVITE sip:[email protected] SIP/2.0
Via: SIP/2.0/TCP src.example.com;branch=z9hG4bKdf6b622b648d9
From: <sip:[email protected]>;tag=35e195d2-947d-4585-946f-09839247
To: <sip:[email protected]>
Call-ID: d253c800-b0d1ea39-4a7dd-3f0e20a
Session-ID: ab30317f1a784dc48ff824d0d3715d86
;remote=f81d4fae7dec11d0a76500a0c91e6bf6
CSeq: 101 INVITE
Max-Forwards: 70
Require: siprec
Accept: application/sdp, application/rs-metadata,
application/rs-metadata-request
Contact: <sip:[email protected]>;+sip.src
Content-Type: multipart/mixed;boundary=foobar
Content-Length: [length]

--foobar
Content-Type: application/SDP
...
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=label:96
a=sendonly
...
m=video 49174 RTP/AVPF 96
a=rtpmap:96 H.264/90000
a=label:97
a=sendonly
...
m=audio 51372 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=label:98
a=sendonly
...
m=video 49176 RTP/AVPF 96
a=rtpmap:96 H.264/90000
a=label:99
a=sendonly
....
--foobar
Content-Type: application/rs-metadata
Content-Disposition: recording-session

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<?xml version="1.0" encoding="UTF-8"?>
<recording xmlns='urn:ietf:params:xml:ns:recording:1'>
<datamode>partial</datamode>
<participantstreamassoc
participant_id="srfBElmCRp2QB23b7Mpk0w==">
<send>i1Pz3to5hGk8fuXl+PbwCw==</send>
<send>UAAMm5GRQKSCMVvLyl4rFw==</send>
<recv>8zc6e0lYTlWIINA6GR+3ag==</recv>
<recv>EiXGlc+4TruqqoDaNE76ag==</recv>
</participantstreamassoc>
<participantstreamassoc
participant_id="zSfPoSvdSDCmU3A3TRDxAw==">
<send>8zc6e0lYTlWIINA6GR+3ag==</send>
<send>EiXGlc+4TruqqoDaNE76ag==</send>
<recv>i1Pz3to5hGk8fuXl+PbwCw==</recv>
<recv>UAAMm5GRQKSCMVvLyl4rFw==</recv>
</participantstreamassoc>
</recording>

3.2.3. Example 3:Call Transfer (RE-INVITE and REFER Based)

A basic call between two participants, Alice and Bob, is connected,
and SRC (a B2BUA acting as SRC as per Section 3.1.1 of [RFC7245]) has
sent a snapshot as described in example 1. Transfer is initiated by
one of the participants (Alice). After the transfer is completed,
the SRC sends a snapshot of the participant changes to the SRS. In
this transfer scenario, Alice drops out after transfer is completed,
Bob and Carol get connected, and recording of media between Bob and
Carol is done by the SRC. There are two flows that can happen here
as described below.

Transfer within the same session (e.g., a RE-INVITE-based transfer):
Alice drops out and Carol is added to the same session. No change to
the session/group element is made. A 'participantsessassoc' XML
element indicating that Alice has disassociated from the CS will be
present in the snapshot. A new 'participant' XML element
representing Carol with mapping to the same RS SDP stream used for
mapping earlier Alice's stream is sent in the snapshot. A new
'sipSessionID' XML element that has Universally Unique Identifier
(UUID) tuples and that corresponds to Bob and Carol is sent in the
snapshot from the SRC to the SRS. Note that one half of the session
ID, that which corresponds to Bob, remains the same.

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RFC 8068 SIP Recording Call Flows February 2017

Metadata snapshot for INVITE based transfer in CS:

RE-INVITE SRC-------------------->SRS

INVITE sip:[email protected] SIP/2.0
Via: SIP/2.0/TCP src.example.com;branch=z9hG4bKdf6b622b648d9
From: <sip:[email protected]>;tag=35e195d2-947d-4585-946f-09839247
To: <sip:[email protected]>
Call-ID: d253c800-b0d1ea39-4a7dd-3f0e20a
Session-ID: ab30317f1a784dc48ff824d0d3715d86
;remote=f81d4fae7dec11d0a76500a0c91e6bf6
CSeq: 101 INVITE
Max-Forwards: 70
Require: siprec
Accept: application/sdp, application/rs-metadata,
application/rs-metadata-request
Contact: <sip:[email protected]>;+sip.src
Content-Type: multipart/mixed;boundary=foobar
Content-Length: [length]

--foobar
Content-Type: application/SDP
...
m=audio 49180 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=label:96
a=sendonly
...
m=video 49182 RTP/AVPF 96
a=rtpmap:96 H.264/90000
a=label:97
a=sendonly
...
m=audio 51374 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=label:98
a=sendonly
...
m=video 49178 RTP/AVPF 96
a=rtpmap:96 H.264/90000
a=label:99
a=sendonly
....
--foobar
Content-Type: application/rs-metadata
Content-Disposition: recording-session

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<?xml version="1.0" encoding="UTF-8"?>
<recording xmlns='urn:ietf:params:xml:ns:recording:1'>
<datamode>partial</datamode>
<session session_id="hVpd7YQgRW2nD22h7q60JQ==">
<sipSessionID>3363127f0d084c10876dddd4f8e5eeb9
;remote=2272bb7e70fe41dba0025ae9a26d54cf</sipSessionID>
</session>
<participant
participant_id="Atnm1ZRnOC6Pm5MApkrDzQ==">
<nameID aor="sip:[email protected]">
<name xml:lang="it">Carol</name>
</nameID>
</participant>
<participantsessionassoc
participant_id="Atnm1ZRnOC6Pm5MApkrDzQ=="
session_id="hVpd7YQgRW2nD22h7q60JQ==">
<associate-time>2013-12-16T23:41:07Z</associate-time>
</participantsessionassoc>
<participantsessionassoc
participant_id="srfBElmCRp2QB23b7Mpk0w=="
session_id="hVpd7YQgRW2nD22h7q60JQ==">
<disassociate-time>2013-12-16T23:41:07Z</disassociate-time>
</participantsessionassoc>
<participantstreamassoc
participant_id="zSfPoSvdSDCmU3A3TRDxAw==">
<send>8zc6e0lYTlWIINA6GR+3ag==</send>
<send>EiXGlc+4TruqqoDaNE76ag==</send>
<recv>60JAJm9UTvik0Ltlih/Gzw==</recv>
<recv>AcR5FUd3Edi8cACQJy/3JQ==</recv>
</participantstreamassoc>
<participantstreamassoc
participant_id="Atnm1ZRnOC6Pm5MApkrDzQ==">
<send>60JAJm9UTvik0Ltlih/Gzw==</send>
<send>AcR5FUd3Edi8cACQJy/3JQ==</send>
<recv>8zc6e0lYTlWIINA6GR+3ag==</recv>
<recv>EiXGlc+4TruqqoDaNE76ag==</recv>
<associate-time>2013-12-16T23:42:07Z</associate-time>
</participantstreamassoc>
</recording>

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RFC 8068 SIP Recording Call Flows February 2017

Transfer with a new session (e.g., REFER-based transfer): in this
case, a new session (CS) is created and shall be part of same CS-
group (done by the SRC).

The SRC first sends an *optional* snapshot indicating disassociation
of the participant from the old CS. An SRC may choose to just send
an INVITE with a new 'session' XML element to implicitly indicate
that the participants are now part of a different CS without sending
disassociation from the old CS. In this example, the SRC uses the
same RS. In case the SRC wishes to use a new RS, it will tear down
the current RS using normal SIP procedures (BYE) with metadata, as in
example 4.

Metadata snapshot for REFER based transfer in CS:

RE-INVITE SRC-------------------->SRS

INVITE sip:[email protected] SIP/2.0
Via: SIP/2.0/TCP src.example.com;branch=z9hG4bKdf6b622b648d9
From: <sip:[email protected]>;tag=35e195d2-947d-4585-946f-09839247
To: <sip:[email protected]>
Call-ID: d253c800-b0d1ea39-4a7dd-3f0e20a
Session-ID: ab30317f1a784dc48ff824d0d3715d86
;remote=f81d4fae7dec11d0a76500a0c91e6bf6
CSeq: 101 INVITE
Max-Forwards: 70
Require: siprec
Accept: application/sdp, application/rs-metadata,
application/rs-metadata-request
Contact: <sip:[email protected]>;+sip.src
Content-Type: multipart/mixed;boundary=foobar
Content-Length: [length]

--foobar
Content-Type: application/SDP
...
m=audio 49180 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=label:96
a=sendonly
...
m=video 49182 RTP/AVPF 96
a=rtpmap:96 H.264/90000
a=label:97
a=sendonly

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...
m=audio 51374 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=label:98
a=sendonly
...
m=video 49178 RTP/AVPF 96
a=rtpmap:96 H.264/90000
a=label:99
a=sendonly
....

--foobar
Content-Type: application/rs-metadata
Content-Disposition: recording-session

<?xml version="1.0" encoding="UTF-8"?>
<recording xmlns='urn:ietf:params:xml:ns:recording:1'>
<datamode>partial</datamode>
<session session_id="hVpd7YQgRW2nD22h7q60JQ==">
<stop-time>2010-12-16T23:41:07Z</stop-time>
</session>
<participantsessionassoc
participant_id="srfBElmCRp2QB23b7Mpk0w=="
session_id="hVpd7YQgRW2nD22h7q60JQ==">
<disassociate-time>2010-12-16T23:41:07Z</disassociate-time>
</participantsessionassoc>
<participantsessionassoc
participant_id="zSfPoSvdSDCmU3A3TRDxAw=="
session_id="hVpd7YQgRW2nD22h7q60JQ==">
<disassociate-time>2010-12-16T23:41:07Z</disassociate-time>
</participantsessionassoc>
</recording>

In the above snapshot, the 'participantsessionassoc' XML element is
optional as indicating a 'session' XML element with a 'stop-time' XML
element implicitly means that all the participants associated with
that session have been disassociated.

The SRC sends another snapshot to indicate the participant change
(due to REFER) and new session information after transfer. In this
example, it is assumed that the SRC uses the same RS to continue
recording the call. The 'sipSessionID' XML element in the metadata
snapshot now indicates Bob and Carol in the (local, remote) UUID
pair.

Ravindranath, et al. Informational [Page 16]

RFC 8068 SIP Recording Call Flows February 2017

Metadata snapshot for REFER based transfer in CS:

RE-INVITE SRC-------------------->SRS

INVITE sip:[email protected] SIP/2.0
Via: SIP/2.0/TCP src.example.com;branch=z9hG4bKdf6b622b648d9
From: <sip:[email protected]>;tag=35e195d2-947d-4585-946f-09839247
To: <sip:[email protected]>
Call-ID: d253c800-b0d1ea39-4a7dd-3f0e20a
Session-ID: ab30317f1a784dc48ff824d0d3715d86
;remote=f81d4fae7dec11d0a76500a0c91e6bf6
CSeq: 101 INVITE
Max-Forwards: 70
Require: siprec
Accept: application/sdp, application/rs-metadata,
application/rs-metadata-request
Contact: <sip:[email protected]>;+sip.src
Content-Type: multipart/mixed;boundary=foobar
Content-Length: [length]

--foobar
Content-Type: application/SDP
...
m=audio 49180 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=label:96
a=sendonly
...
m=video 49182 RTP/AVPF 96
a=rtpmap:96 H.264/90000
a=label:97
a=sendonly
...
m=audio 51374 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=label:98
a=sendonly
...
m=video 49178 RTP/AVPF 96
a=rtpmap:96 H.264/90000
a=label:99
a=sendonly
....

--foobar
Content-Type: application/rs-metadata

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RFC 8068 SIP Recording Call Flows February 2017

<?xml version="1.0" encoding="UTF-8"?>
<recording xmlns='urn:ietf:params:xml:ns:recording:1'>
<datamode>complete</datamode>
<session session_id="bfLZ+NTFEeCNxQTuRyQBmw==">
<sipSessionID>3363127f0d084c10876dddd4f8e5eeb9
;remote=2272bb7e70fe41dba0025ae9a26d54cf</sipSessionID>
<start-time>2010-12-16T23:41:07Z</start-time>
</session>
<participant
participant_id="zSfPoSvdSDCmU3A3TRDxAw==">
<nameID aor="sip:[email protected]"/>
</participant>
<participant
participant_id="Atnm1ZRnOC6Pm5MApkrDzQ==">
<nameID aor="sip:[email protected]"/>
</participant>
<stream stream_id="60JAJm9UTvik0Ltlih/Gzw=="
session_id="bfLZ+NTFEeCNxQTuRyQBmw==">
<label>96</label>
</stream>
<stream stream_id="AcR5FUd3Edi8cACQJy/3JQ=="
session_id="bfLZ+NTFEeCNxQTuRyQBmw==">
<label>97</label>
</stream>
<stream stream_id="8zc6e0lYTlWIINA6GR+3ag=="
session_id="bfLZ+NTFEeCNxQTuRyQBmw==">
<label>98</label>
</stream>
<stream stream_id="EiXGlc+4TruqqoDaNE76ag=="
session_id="bfLZ+NTFEeCNxQTuRyQBmw==">
<label>99</label>
</stream>
<participantsessionassoc
participant_id="zSfPoSvdSDCmU3A3TRDxAw=="
session_id="bfLZ+NTFEeCNxQTuRyQBmw==">
<associate-time>2010-12-16T23:32:03Z</associate-time>
</participantsessionassoc>
<participantsessionassoc
participant_id="Atnm1ZRnOC6Pm5MApkrDzQ=="
session_id="bfLZ+NTFEeCNxQTuRyQBmw==">
<associate-time>2010-12-16T23:41:07Z</associate-time>
</participantsessionassoc>
<participantstreamassoc
participant_id="zSfPoSvdSDCmU3A3TRDxAw==">
<send>8zc6e0lYTlWIINA6GR+3ag==</send>
<send>EiXGlc+4TruqqoDaNE76ag==</send>
<recv>60JAJm9UTvik0Ltlih/Gzw==</recv>
<recv>AcR5FUd3Edi8cACQJy/3JQ==</recv>

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RFC 8068 SIP Recording Call Flows February 2017

</participantstreamassoc>
<participantstreamassoc
participant_id="Atnm1ZRnOC6Pm5MApkrDzQ==">
<send>60JAJm9UTvik0Ltlih/Gzw==</send>
<send>AcR5FUd3Edi8cACQJy/3JQ==</send>
<recv>8zc6e0lYTlWIINA6GR+3ag==</recv>
<recv>EiXGlc+4TruqqoDaNE76ag==</recv>
</participantstreamassoc>
</recording>

3.2.4. Example 4: Call Disconnect

This example shows a snapshot of metadata sent by the SRC to the SRS
when a CS with Alice and Bob as participants is disconnected.

SRC SRS
| |
|(1) BYE (metadata snapshot) F1 |
|---------------------------------------------------->|
| 200 OK F2 |
|<----------------------------------------------------|

Metadata snapshot for a CS disconnect:

F1 BYE SRC -----------> SRS

BYE sip:[email protected] SIP/2.0
Via: SIP/2.0/UDP src.example.com;branch=z9hG4bK47c8eb30
From: <sip:[email protected]>;tag=35e195d2-947d-4585-946f-09839247
To: <sip:[email protected]>
Call-ID: d253c800-b0d1ea39-4a7dd-3f0e20a
Session-ID: ab30317f1a784dc48ff824d0d3715d86
;remote=f81d4fae7dec11d0a76500a0c91e6bf6
CSeq: 102 BYE
Max-Forwards: 70
Require: siprec
Accept: application/rs-metadata,
application/rs-metadata-request
Contact: <sip:[email protected]>;+sip.src
Content-Type: multipart/mixed;boundary=foobar
Content-Length: [length]

--foobar
Content-Type: application/rs-metadata

Ravindranath, et al. Informational [Page 19]

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<?xml version="1.0" encoding="UTF-8"?>
<recording xmlns='urn:ietf:params:xml:ns:recording:1'>
<datamode>partial</datamode>
<session session_id="hVpd7YQgRW2nD22h7q60JQ==">
<stop-time>2010-12-16T23:41:07Z</stop-time>
</session>
<participantsessionassoc
participant_id="srfBElmCRp2QB23b7Mpk0w=="
session_id="hVpd7YQgRW2nD22h7q60JQ==">
<disassociate-time>2010-12-16T23:41:07Z</disassociate-time>
</participantsessionassoc>

<participantsessionassoc
participant_id="zSfPoSvdSDCmU3A3TRDxAw=="
session_id="hVpd7YQgRW2nD22h7q60JQ==">
<disassociate-time>2010-12-16T23:41:07Z</disassociate-time>
</participantsessionassoc>
</recording>

3.3. Call Scenarios with SRC Recording Streams by Mixing

This section describes a few example call flows where the SRC may be
part of conference model either as focus or a participant in
conference as explained in Section 3.1.5 of [RFC7245]. The SRS here
can be a SIP User Agent (UA) or an entity part of the MEDIACTRL
architecture. Note that the disconnect case is not shown since the
metadata snapshot will be same as for a non-mixing case.

3.3.1. Example 1: Basic Call with SRC Mixing Streams

A basic call between two participants, Alice and Bob, who are part of
one CS. In this use case, each participant calls into a conference
server (say, a Multipoint Control Unit (MCU)) to attend one of many
conferences hosted on or managed by that server. Media streams sent
by each participant are received by all the other participants in the
conference. Below is the initial snapshot sent by the SRC in the
INVITE to the SRS that has the complete metadata. For the sake of
simplicity, only snippets of SIP/SDP are shown. The SRC records the
streams of each participant to SRS by mixing in this example. The
SRC here is part of conference model described in Section 3 of
[RFC7245] as a focus and does mixing. The SRC here is not a
participant by itself and hence it does not contribute to media.

Ravindranath, et al. Informational [Page 20]

RFC 8068 SIP Recording Call Flows February 2017

Metadata snapshot with the SRC mixing streams to the SRS:

F1 INVITE SRC --------------> SRS

INVITE sip:[email protected] SIP/2.0
Via: SIP/2.0/TCP src.example.com;branch=z9hG4bKdf6b622b648d9
From: <sip:[email protected]>;tag=35e195d2-947d-4585-946f-09839247
To: <sip:[email protected]>
Call-ID: d253c800-b0d1ea39-4a7dd-3f0e20a
Session-ID: a358d2b81a444a8c8fb05950cef331e7
;remote=00000000000000000000000000000000
CSeq: 101 INVITE
Max-Forwards: 70
Require: siprec
Accept: application/sdp, application/rs-metadata,
application/rs-metadata-request
Contact: <sip:[email protected]>;+sip.src
Content-Type: multipart/mixed;boundary=foobar
Content-Length: [length]

--foobar
Content-Type: application/SDP
...
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=label:96
a=sendonly

....
--foobar
Content-Type: application/rs-metadata
Content-Disposition: recording-session

<?xml version="1.0" encoding="UTF-8"?>
<recording xmlns='urn:ietf:params:xml:ns:recording:1'>
<datamode>complete</datamode>
<session session_id="hVpd7YQgRW2nD22h7q60JQ==">
<sipSessionID>fa3b60f27e91441e84c55a9a0095f075
;remote=a358d2b81a444a8c8fb05950cef331e7</sipSessionID>
<sipSessionID>ca718e1430474b5485a53aa5d0bea45e
;remote=68caf509b9284b7ea45f84a049febf0a</sipSessionID>
<start-time>2010-12-16T23:41:07Z</start-time>
</session>
<participant
participant_id="srfBElmCRp2QB23b7Mpk0w==">
<nameID aor="sip:[email protected]">
<name xml:lang="it">Alice</name>
</nameID>

Ravindranath, et al. Informational [Page 21]

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</participant>
<participant
participant_id="zSfPoSvdSDCmU3A3TRDxAw==">
<nameID aor="sip:[email protected]">
<name xml:lang="it">Bob</name>
</nameID>
</participant>
<stream stream_id="i1Pz3to5hGk8fuXl+PbwCw=="
session_id="hVpd7YQgRW2nD22h7q60JQ==">
<label>96</label>
</stream>
<participantsessionassoc
participant_id="srfBElmCRp2QB23b7Mpk0w=="
session_id="hVpd7YQgRW2nD22h7q60JQ==">
<associate-time>2010-12-16T23:41:07Z</associate-time>
</participantsessionassoc>
<participantsessionassoc
participant_id="zSfPoSvdSDCmU3A3TRDxAw=="
session_id="hVpd7YQgRW2nD22h7q60JQ==">
<associate-time>2010-12-16T23:41:07Z</associate-time>
</participantsessionassoc>
<participantstreamassoc
participant_id="srfBElmCRp2QB23b7Mpk0w==">
<send>i1Pz3to5hGk8fuXl+PbwCw==</send>
<recv>i1Pz3to5hGk8fuXl+PbwCw==</recv>
</participantstreamassoc>

<participantstreamassoc
participant_id="zSfPoSvdSDCmU3A3TRDxAw==">
<send>i1Pz3to5hGk8fuXl+PbwCw==</send>
<recv>i1Pz3to5hGk8fuXl+PbwCw==</recv>
</participantstreamassoc>
</recording>

In the above example, there are two participants, Alice and Bob, in
the conference. Among other things, the SRC sends Session-ID in the
metadata snapshot. There are two Session-IDs here: one that
corresponds to the SIP session between Alice and the Conference focus
and the other for the SIP session between Bob and the Conference
focus. In this use case, since Alice and Bob call into the
conference, these Session-IDs are different.

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RFC 8068 SIP Recording Call Flows February 2017

3.3.2. Example 2: Hold/Resume with SRC Recording by Mixing Streams

This is the continuation of example 1 (basic call with SRC mixing
streams). A call between two participants, Alice and Bob, is
established and an RS is created for recording, as in example 5. One
of the participants, Bob, puts Alice on hold, and then resumes as
part of the same CS. The 'send' and 'recv' XML elements of a
'participant' XML element are used to indicate whether or not a
participant is contributing to a media stream. The metadata snapshot
is represented below:

During hold

Metadata snapshot when a CS participant goes on hold
and the SRC is mixing the streams:

RE-INVITE SRC --------------> SRS

INVITE sip:[email protected] SIP/2.0
Via: SIP/2.0/TCP src.example.com;branch=z9hG4bKdf6b622b648d9
From: <sip:[email protected]>;tag=35e195d2-947d-4585-946f-09839247
To: <sip:[email protected]>
Call-ID: d253c800-b0d1ea39-4a7dd-3f0e20a
Session-ID: a358d2b81a444a8c8fb05950cef331e7
;remote=f81d4fae7dec11d0a76500a0c91e6bf6
CSeq: 101 INVITE
Max-Forwards: 70
Require: siprec
Accept: application/sdp, application/rs-metadata,
application/rs-metadata-request
Contact: <sip:[email protected]>;+sip.src
Content-Type: multipart/mixed;boundary=foobar
Content-Length: [length]

--foobar
Content-Type: application/SDP
...
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=label:96
a=sendonly

....
--foobar
Content-Type: application/rs-metadata
Content-Disposition: recording-session

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<?xml version="1.0" encoding="UTF-8"?>
<recording xmlns='urn:ietf:params:xml:ns:recording:1'>
<datamode>partial</datamode>
<stream stream_id="i1Pz3to5hGk8fuXl+PbwCw=="
session_id="hVpd7YQgRW2nD22h7q60JQ==">
<label>96</label>
</stream>
<participantstreamassoc
participant_id="srfBElmCRp2QB23b7Mpk0w==">
<recv>i1Pz3to5hGk8fuXl+PbwCw==</recv>
</participantstreamassoc>
<participantstreamassoc
participant_id="zSfPoSvdSDCmU3A3TRDxAw==">
<send>i1Pz3to5hGk8fuXl+PbwCw==</send>
</participantstreamassoc>
</recording>

During resumption, a snapshot shown below will be sent from the SRC
to the SRS.

Metadata snapshot when a CS participant resumes and
the SRC is mixing the streams:

RE-INVITE SRC --------------> SRS

INVITE sip:[email protected] SIP/2.0
Via: SIP/2.0/TCP src.example.com;branch=z9hG4bKdf6b622b648d9
From: <sip:[email protected]>;tag=35e195d2-947d-4585-946f-09839247
To: <sip:[email protected]>
Call-ID: d253c800-b0d1ea39-4a7dd-3f0e20a
Session-ID: a358d2b81a444a8c8fb05950cef331e7
;remote=f81d4fae7dec11d0a76500a0c91e6bf6
CSeq: 101 INVITE
Max-Forwards: 70
Require: siprec
Accept: application/sdp, application/rs-metadata,
application/rs-metadata-request
Contact: <sip:[email protected]>;+sip.src
Content-Type: multipart/mixed;boundary=foobar
Content-Length: [length]

Ravindranath, et al. Informational [Page 24]

RFC 8068 SIP Recording Call Flows February 2017

--foobar
Content-Type: application/SDP
...
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=label:96
a=sendonly

....
--foobar
Content-Type: application/rs-metadata
Content-Disposition: recording-session

<?xml version="1.0" encoding="UTF-8"?>
<recording xmlns='urn:ietf:params:xml:ns:recording:1'>
<datamode>partial</datamode>
<stream stream_id="i1Pz3to5hGk8fuXl+PbwCw=="
session_id="hVpd7YQgRW2nD22h7q60JQ==">
<label>96</label>
</stream>
<participantstreamassoc
participant_id="srfBElmCRp2QB23b7Mpk0w==">
<send>i1Pz3to5hGk8fuXl+PbwCw==</send>
<recv>i1Pz3to5hGk8fuXl+PbwCw==</recv>
</participantstreamassoc>
<participantstreamassoc
participant_id="zSfPoSvdSDCmU3A3TRDxAw==">
<send>i1Pz3to5hGk8fuXl+PbwCw==</send>
<recv>i1Pz3to5hGk8fuXl+PbwCw==</recv>
</participantstreamassoc>
</recording>

3.3.3. Example 3: Metadata Snapshot of Joining/Dropping of a
Participant to a Session

In a conference model, participants can join and drop a session any
time during the session. Below is a snapshot sent from the SRC to
the SRS in this case. Note the SRC here can be a focus or a
participant in the conference. In the case where the SRC is a
participant, it may learn the information required for metadata by
subscribing to a conference event package [RFC4575]. Assume Alice
and Bob were in the conference and a third participant (Carol) joins,
then the SRC sends the below snapshot with the indication of new
participant.

Ravindranath, et al. Informational [Page 25]

RFC 8068 SIP Recording Call Flows February 2017

Metadata snapshot for a new participant joining CS:

RE-INVITE SRC --------------> SRS

INVITE sip:[email protected] SIP/2.0
Via: SIP/2.0/TCP src.example.com;branch=z9hG4bKdf6b622b648d9
From: <sip:[email protected]>;tag=35e195d2-947d-4585-946f-09839247
To: <sip:[email protected]>
Call-ID: d253c800-b0d1ea39-4a7dd-3f0e20a
Session-ID: a358d2b81a444a8c8fb05950cef331e7
;remote=f81d4fae7dec11d0a76500a0c91e6bf6
CSeq: 101 INVITE
Max-Forwards: 70
Require: siprec
Accept: application/sdp, application/rs-metadata,
application/rs-metadata-request
Contact: <sip:[email protected]>;+sip.src
Content-Type: multipart/mixed;boundary=foobar
Content-Length: [length]

--foobar
Content-Type: application/SDP
...
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=label:96
a=sendonly

....
--foobar
Content-Type: application/rs-metadata
Content-Disposition: recording-session

<?xml version="1.0" encoding="UTF-8"?>
<recording xmlns='urn:ietf:params:xml:ns:recording:1'>
<datamode>partial</datamode>
<session session_id="hVpd7YQgRW2nD22h7q60JQ==">
<sipSessionID>fa3b60f27e91441e84c55a9a0095f075
;remote=a358d2b81a444a8c8fb05950cef331e7</sipSessionID>
<sipSessionID>ca718e1430474b5485a53aa5d0bea45e
;remote=68caf509b9284b7ea45f84a049febf0a</sipSessionID>
<sipSessionID>497c0f13929643b4a16858e2a3885edc
;remote=0e8a82bedda74f57be4a4a4da54167c4</sipSessionID>
</session>
<participant
participant_id="Atnm1ZRnOC6Pm5MApkrDzQ==">
<nameID aor="sip:[email protected]">
<name xml:lang="it">Carol</name>

Ravindranath, et al. Informational [Page 26]

RFC 8068 SIP Recording Call Flows February 2017

</nameID>
</participant>
<participantsessionassoc
participant_id="Atnm1ZRnOC6Pm5MApkrDzQ=="
session_id="hVpd7YQgRW2nD22h7q60JQ==">
<associate-time>2013-12-16T23:41:07Z</associate-time>
</participantsessionassoc>
<participantstreamassoc
participant_id="Atnm1ZRnOC6Pm5MApkrDzQ==">
<send>i1Pz3to5hGk8fuXl+PbwCw==</send>
<recv>i1Pz3to5hGk8fuXl+PbwCw==</recv>
</participantstreamassoc>
</recording>

After some time, Alice drops from the conference. The SRC generates
a new snapshot showing Alice disassociating from the session.

Metadata snapshot for a participant dropping from CS:

RE-INVITE SRC --------------> SRS

INVITE sip:[email protected] SIP/2.0
Via: SIP/2.0/TCP src.example.com;branch=z9hG4bKdf6b622b648d9
From: <sip:[email protected]>;tag=35e195d2-947d-4585-946f-09839247
To: <sip:[email protected]>
Call-ID: d253c800-b0d1ea39-4a7dd-3f0e20a
Session-ID: a358d2b81a444a8c8fb05950cef331e7
;remote=f81d4fae7dec11d0a76500a0c91e6bf6
CSeq: 101 INVITE
Max-Forwards: 70
Require: siprec
Accept: application/sdp, application/rs-metadata,
application/rs-metadata-request
Contact: <sip:[email protected]>;+sip.src
Content-Type: multipart/mixed;boundary=foobar
Content-Length: [length]

--foobar
Content-Type: application/SDP
...
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=label:96
a=sendonly

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....
--foobar
Content-Type: application/rs-metadata
Content-Disposition: recording-session

<?xml version="1.0" encoding="UTF-8"?>
<recording xmlns='urn:ietf:params:xml:ns:recording:1'>
<datamode>partial</datamode>
<session session_id="hVpd7YQgRW2nD22h7q60JQ==">
<sipSessionID>ca718e1430474b5485a53aa5d0bea45e
;remote=68caf509b9284b7ea45f84a049febf0a</sipSessionID>
<sipSessionID>497c0f13929643b4a16858e2a3885edc
;remote=0e8a82bedda74f57be4a4a4da54167c4</sipSessionID>
</session>
<participantsessionassoc
participant_id="srfBElmCRp2QB23b7Mpk0w=="
session_id="hVpd7YQgRW2nD22h7q60JQ==">
<disassociate-time>2010-12-16T23:41:07Z</disassociate-time>
</participantsessionassoc>
</recording>

3.3.4. Example 4: Call Disconnect

When a CS is disconnected, the SRC sends a BYE with a snapshot of
metadata having a session stop time and participant disassociation
times. The snapshot looks the same as listed in Section 3.2.4.

3.4. Call Scenarios with Persistent RS between SRC and SRS

This section shows the snapshots of metadata for the cases where a
persistent RS exists between the SRC and the SRS. An SRC here may be
a SIP UA or a B2BUA, or it may be part of a conference model as
either the focus or a participant in a conference. The SRS here
could be a SIP UA or an entity part of the MEDIACTRL architecture.
Except in the disconnect case, the snapshot remains same as mentioned
in previous sections.

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RFC 8068 SIP Recording Call Flows February 2017

3.4.1. Example 1: Metadata Snapshot during CS Disconnect with
Persistent RS between SRC and SRS

Metadata snapshot for a CS disconnect with a persistent RS:

RE-INVITE sent from SRC -----------> SRS

INVITE sip:[email protected] SIP/2.0
Via: SIP/2.0/UDP src.example.com;branch=z9hG4bK47c8eb30
From: <sip:[email protected]>;tag=35e195d2-947d-4585-946f-09839247
To: <sip:[email protected]>
Call-ID: d253c800-b0d1ea39-4a7dd-3f0e20a
Session-ID: ab30317f1a784dc48ff824d0d3715d86
;remote=f81d4fae7dec11d0a76500a0c91e6bf6
CSeq: 101 INVITE
Max-Forwards: 70
Require: siprec
Accept: application/rs-metadata,
application/rs-metadata-request
Contact: <sip:[email protected]>;+sip.src
Content-Type: multipart/mixed;boundary=foobar
Content-Length: [length]

--foobar
Content-Type: application/rs-metadata

<?xml version="1.0" encoding="UTF-8"?>
<recording xmlns='urn:ietf:params:xml:ns:recording:1'>
<datamode>partial</datamode>
<session session_id="hVpd7YQgRW2nD22h7q60JQ==">
<stop-time>2010-12-16T23:41:07Z</stop-time>
</session>
<participantsessionassoc
participant_id="srfBElmCRp2QB23b7Mpk0w=="
session_id="hVpd7YQgRW2nD22h7q60JQ==">
<disassociate-time>2010-12-16T23:41:07Z</disassociate-time>
</participantsessionassoc>

<participantsessionassoc
participant_id="zSfPoSvdSDCmU3A3TRDxAw=="
session_id="hVpd7YQgRW2nD22h7q60JQ==">
<disassociate-time>2010-12-16T23:41:07Z</disassociate-time>
</participantsessionassoc>
</recording>

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3.5. Turret-Case: Multiple CS into Single RS with Mixed Stream

In trading-floor environments, in order to minimize storage and
recording system resources, it may be preferable to mix multiple
concurrent calls (each call is one CS) on different handsets/speakers
on the same turret into a single RS. This would mean media in each
CS is mixed and recorded as part of single media stream, and multiple
such CSs are recording in one RS from an SRC to an SRS.

Taking an example where there are two CSs [CS1 and CS2]: assume
mixing is done in each of these CSs and both these CSs are recorded
as part of single RS from a single SRC, which is part of both the
CSs. There are three possibilities here:

o CS1 and CS2 use the same focus for mixing, and that focus is also
acting as SRC in each of the CSs.

o One CS (e.g. CS1) SRC is the focus and the other CS (e.g. CS2),
SRC is just one of the participants of the conference.

o In both CS1 and CS2, the SRC is just a participant of conference.

The following example shows the first possibility where CS1 and CS2
use the same focus for mixing, and that focus is also acting as SRC
in each of the CSs.

Metadata snapshot with two CSs recorded as part of the same RS:

INVITE SRC --------------> SRS

INVITE sip:[email protected] SIP/2.0
Via: SIP/2.0/TCP src.example.com;branch=z9hG4bKdf6b622b648d9
From: <sip:[email protected]>;tag=35e195d2-947d-4585-946f-09839247
To: <sip:[email protected]>
Call-ID: d253c800-b0d1ea39-4a7dd-3f0e20a
Session-ID: a358d2b81a444a8c8fb05950cef331e7
;remote=00000000000000000000000000000000
Content-Type: application/SDP
...
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=label:96
a=sendonly
...

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<?xml version="1.0" encoding="UTF-8"?>
<recording xmlns='urn:ietf:params:xml:ns:recording:1'>
<datamode>complete</datamode>
<group group_id="7+OTCyoxTmqmqyA/1weDAg==">
<associate-time>2010-12-16T23:41:07Z</associate-time>
</group>
<session session_id="hVpd7YQgRW2nD22h7q60JQ==">
<sipSessionID>fa3b60f27e91441e84c55a9a0095f075
;remote=a358d2b81a444a8c8fb05950cef331e7</sipSessionID>
<sipSessionID>ca718e1430474b5485a53aa5d0bea45e
;remote=a358d2b81a444a8c8fb05950cef331e7</sipSessionID>
<sipSessionID>497c0f13929643b4a16858e2a3885edc
;remote=a358d2b81a444a8c8fb05950cef331e7</sipSessionID>
<group-ref>7+OTCyoxTmqmqyA/1weDAg==</group-ref>
<start-time>2010-12-16T23:41:07Z</start-time>
</session>
<session session_id="e6370VVGEeWAG6886p18uA==">
<sipSessionID>ae10731ca50343a5aaae2dd0904a65de
;remote=a358d2b81a444a8c8fb05950cef331e7</sipSessionID>
<sipSessionID>33c77aac7deb414cbc8c10f363fccb71
;remote=a358d2b81a444a8c8fb05950cef331e7</sipSessionID>
<sipSessionID>fd6932e9e5fc489fae2d5b3779723b7e
;remote=a358d2b81a444a8c8fb05950cef331e7</sipSessionID>
<group-ref>7+OTCyoxTmqmqyA/1weDAg==</group-ref>
<start-time>2010-12-16T23:43:07Z</start-time>
</session>
<participant
participant_id="srfBElmCRp2QB23b7Mpk0w==">
<nameID aor="sip:[email protected]">
<name xml:lang="it">Alice</name>
</nameID>
</participant>
<participant
participant_id="zSfPoSvdSDCmU3A3TRDxAw==">
<nameID aor="sip:[email protected]">
<name xml:lang="it">Bob</name>
</nameID>
</participant>
<participant
participant_id="EiXGlc+4TruqqoDaNE76ag==">
<nameID aor="sip:[email protected]">
<name xml:lang="it">Carol</name>
</nameID>
</participant>
<stream stream_id="UAAMm5GRQKSCMVvLyl4rFw=="
session_id="hVpd7YQgRW2nD22h7q60JQ==">
<label>96</label>
</stream>

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<participantsessionassoc
participant_id="srfBElmCRp2QB23b7Mpk0w=="
session_id="hVpd7YQgRW2nD22h7q60JQ==">
<associate-time>2010-12-16T23:41:07Z</associate-time>
</participantsessionassoc>
<participantsessionassoc
participant_id="zSfPoSvdSDCmU3A3TRDxAw=="
session_id="hVpd7YQgRW2nD22h7q60JQ==">
<associate-time>2010-12-16T23:41:07Z</associate-time>
</participantsessionassoc>
<participantsessionassoc
participant_id="zSfPoSvdSDCmU3A3TRDxAw=="
session_id="e6370VVGEeWAG6886p18uA==">
<associate-time>2010-12-16T23:43:07Z</associate-time>
</participantsessionassoc>
<participantsessionassoc
participant_id="EiXGlc+4TruqqoDaNE76ag=="
session_id="e6370VVGEeWAG6886p18uA==">
<associate-time>2010-12-16T23:43:07Z</associate-time>
</participantsessionassoc>

<participantstreamassoc
participant_id="srfBElmCRp2QB23b7Mpk0w==">
<send>UAAMm5GRQKSCMVvLyl4rFw==</send>
<recv>UAAMm5GRQKSCMVvLyl4rFw==</recv>
</participantstreamassoc>
<participantstreamassoc
participant_id="zSfPoSvdSDCmU3A3TRDxAw==">
<send>UAAMm5GRQKSCMVvLyl4rFw==</send>
<recv>UAAMm5GRQKSCMVvLyl4rFw==</recv>
</participantstreamassoc>
<participantstreamassoc
participant_id="EiXGlc+4TruqqoDaNE76ag==">
<send>UAAMm5GRQKSCMVvLyl4rFw==</send>
<recv>UAAMm5GRQKSCMVvLyl4rFw==</recv>
</participantstreamassoc>
</recording>

4. Security Considerations

Security and privacy considerations mentioned in [RFC7865] and
[RFC7866] have to be followed by the SRC and the SRS for setting up
RS SIP dialogs and sending metadata.

5. IANA Considerations

This document does not require any IANA actions.

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RFC 8068 SIP Recording Call Flows February 2017

6. References

6.1. Normative References

[RFC6341] Rehor, K., Ed., Portman, L., Ed., Hutton, A., and R. Jain,
"Use Cases and Requirements for SIP-Based Media Recording
(SIPREC)", RFC 6341, DOI 10.17487/RFC6341, August 2011,
<http://www.rfc-editor.org/info/rfc6341>.

[RFC7865] Ravindranath, R., Ravindran, P., and P. Kyzivat, "Session
Initiation Protocol (SIP) Recording Metadata", RFC 7865,
DOI 10.17487/RFC7865, May 2016,
<http://www.rfc-editor.org/info/rfc7865>.

[RFC7866] Portman, L., Lum, H., Ed., Eckel, C., Johnston, A., and A.
Hutton, "Session Recording Protocol", RFC 7866,
DOI 10.17487/RFC7866, May 2016,
<http://www.rfc-editor.org/info/rfc7866>.

[RFC7245] Hutton, A., Ed., Portman, L., Ed., Jain, R., and K. Rehor,
"An Architecture for Media Recording Using the Session
Initiation Protocol", RFC 7245, DOI 10.17487/RFC7245, May
2014, <http://www.rfc-editor.org/info/rfc7245>.

6.2. Informative References

[RFC4575] Rosenberg, J., Schulzrinne, H., and O. Levin, Ed., "A
Session Initiation Protocol (SIP) Event Package for
Conference State", RFC 4575, DOI 10.17487/RFC4575, August
2006, <http://www.rfc-editor.org/info/rfc4575>.

[RFC4353] Rosenberg, J., "A Framework for Conferencing with the
Session Initiation Protocol (SIP)", RFC 4353,
DOI 10.17487/RFC4353, February 2006,
<http://www.rfc-editor.org/info/rfc4353>.

[RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
A., Peterson, J., Sparks, R., Handley, M., and E.
Schooler, "SIP: Session Initiation Protocol", RFC 3261,
DOI 10.17487/RFC3261, June 2002,
<http://www.rfc-editor.org/info/rfc3261>.

[RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session
Description Protocol", RFC 4566, DOI 10.17487/RFC4566,
July 2006, <http://www.rfc-editor.org/info/rfc4566>.

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Acknowledgements

Thanks to Ofir Rath, Charles Eckel, Yaron Pdut, Dmitry Andreyev, and
Charles Armitage for their review comments.

Thanks to Alissa Cooper, Stephen Farrell, Kathleen Moriarty, Suresh
Krishnan, Benoit Claise, Carlos Pignataro, Dan Romascanu, and Derek
Atkins for their feedback and comments during IESG reviews.

Authors' Addresses

Ram Mohan Ravindranath
Cisco Systems, Inc.
Cessna Business Park,
Kadabeesanahalli Village, Varthur Hobli,
Sarjapur-Marathahalli Outer Ring Road
Bangalore, Karnataka 560103
India

Email: [email protected]

Parthasarathi Ravindran
Nokia Networks
Bangalore, Karnataka
India

Email: [email protected]

Paul Kyzivat
Huawei
Hudson, MA
United States of America

Email: [email protected]

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