SIPREC                                           Ram Mohan. Ravindranath
Internet-Draft                                       Cisco Systems, Inc.
Intended status: Standards Track                Parthasarathi. Ravindran
Expires: January 22, September 1, 2015                                Nokia Networks
                                                           Paul. Kyzivat
                                                                  Huawei
                                                           July 21, 2014
                                                       February 28, 2015

         Session Initiation Protocol (SIP) Recording Call Flows
                     draft-ietf-siprec-callflows-03
                     draft-ietf-siprec-callflows-04

Abstract

   Session recording is a critical requirement in many communications
   environments such as call centers and financial trading.  In some of
   these environments, all calls must be recorded for regulatory,
   compliance, and consumer protection reasons.  Recording of a session
   is typically performed by sending a copy of a media stream to a
   recording device.  This document lists call flows that has snapshot
   of metadata sent from SRC to SRS, the metadata format for which is
   described in [I-D.ietf-siprec-metadata] . SRS.  This is purely an informational
   document that is written to support the model defined in the metadata
   draft.

Status of this Memo

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   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on January 22, September 1, 2015.

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Table of Contents

   1.  Overview . . . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  3
   3.  Metadata XML schema Instances  . . . . . . . . . . . . . . . .  3
     3.1.  Sample Call flow . . . . . . . . . . . . . . . . . . . . .  3
     3.2.  Call Scenarios with SRC recording streams with out
           mixing . . . . . . . . . . . . . . . . . . . . . . . . . .  5
       3.2.1.  Example 1: Basic Call  . . . . . . . . . . . . . . . .  5
       3.2.2.  Example 2: Hold/resume . . . . . . . . . . . . . . . .  7
       3.2.3.  Example 3:Call Transfer (RE-INVITE and REFER based)  . 10 11
       3.2.4.  Example 4: Call disconnect . . . . . . . . . . . . . . 17
     3.3.  Call Scenarios with SRC recording streams by mixing  . . . 19
       3.3.1.  Example 1: Basic call with SRC mixing streams  . . . . 19
       3.3.2.  Example 2: Hold/resume with SRC recording by
               mixing streams . . . . . . . . . . . . . . . . . . . . 21
       3.3.3.  Example 3: Metadata snapshot of joining/dropping
               of a participant to a session  . . . . . . . . . . . . 24 25
       3.3.4.  Example 4: Call disconnect . . . . . . . . . . . . . . 27 28
     3.4.  Call scenarios with persistent RS between SRC and SRS  . . 27 28
       3.4.1.  Example 1: Metadata snapshot during CS disconnect
               with persistent RS between SRC and SRS . . . . . . . . 27 28
     3.5.  Turrent-Case: Multiple CS into single RS with mixed
           stream . . . . . . . . . . . . . . . . . . . . . . . . . . 28 29
   4.  Security Considerations  . . . . . . . . . . . . . . . . . . . 30 32
   5.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 30 32
   6.  Acknowledgement  . . . . . . . . . . . . . . . . . . . . . . . 31 32
   7.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 31 33
     7.1.  Normative References . . . . . . . . . . . . . . . . . . . 31 33
     7.2.  Informative References . . . . . . . . . . . . . . . . . . 31 33
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 31 33

1.  Overview

   [I-D.ietf-siprec-metadata] document focuses on the Recording metadata
   which describes the communication session.  The document lists a few
   examples and shows the snapshots of metadata sent from SRC to SRS.
   For the sake of simplicity the entire SIP [RFC3261] messages are not
   shown at various points, instead only a snippets of the SIP/SDP
   messages and the XML snapshot of metadata is shown.

2.  Terminology

   The terms using in this defined are defined in
   [I-D.ietf-siprec-metadata].  No new terms/definitions are introduced
   in this document.

3.  Metadata XML schema Instances

   This section describes the metadata model XML instances for different
   use cases of SIPREC.  For the sake of simplicity the complete SIP/SDP
   snippets are NOT shown here.

3.1.  Sample Call flow

   The following is a sample call flow that shows the SRC establishing a
   recording session towards the SRS.  The SRC in this example could be
   part of any one of the architectures described in section 3 of
   [RFC7245].

               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 describes the snapshot of metadata
   sent from SRC to SRS for each of the above transactions (F1 ...
   Fn-1).  There may be multiple UPDATES/RE-INVITES mid call to
   indicates snapshots of different CS changes.  Depending on the
   architecture described in section 3 of [RFC7245] an SRC may be a
   endpoint or B2BUA or as part of MEDIACTRL or Conference Focus.  The
   subsequent sections in this document tries to list some example
   metadata snapshots for three major categories.

   o  SRC recording streams unmixed to SRS.  This includes cases where
      SRC is SIP UA or B2BUA.
   o  SRC recording mixed streams to SRS.  This includes cases where SRC
      is part of SIP conference model explained in [RFC4353] [RFC4353].
   o  SRC having a persistent RS with SRS SRS.
   o  Special flows like Turrent flows flows.

   Note that only those examples for which metadata changes are listed
   in each category.  For some of the call flows the snapshots may be
   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 with out mixing

   The section covers the models mentioned in the architecture document
   in section 3 of [RFC7245] where an SRC may be a SIP-UA or B2BUA.  The
   SRS here could be a SIP-UA or an entity part of MEDIACTRL
   architecture described in [RFC6230].

3.2.1.  Example 1: Basic Call

   Basic call between two Participants Alice and Bob who are part of one
   CS.  In this use case each participant sends two Media Streams.
   Media Streams sent by each participant are received all other
   participants 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 that has complete metadata.  For the sake of simplicity only
   snippets of SIP/SDP are shown.  The SRCs records the streams of each
   participant to SRS with out mixing in this example.

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

      INVITE sip:recorder@example.com SIP/2.0
      Via: SIP/2.0/TCP src.example.com;branch=z9hG4bKdf6b622b648d9
      From: <sip:2000@example.com>;tag=35e195d2-947d-4585-946f-09839247
      To: <sip:recorder@example.com>
      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:2000@src.example.com>;+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
   <?xml version="1.0" encoding="UTF-8"?>
       <recording xmlns='urn:ietf:params:xml:ns:recording'>
              <datamode>complete</datamode>
         <session session_id="hVpd7YQgRW2nD22h7q60JQ==">
            <start-time>2010-12-16T23:41:07Z</start-time>
            <sipSessionID>47755a9de7794ba387653f2099600ef2
            ;remote=3363127f0d084c10876dddd4f8e5eeb9</sipSessionID>
         </session>
          <participant
             participant_id="srfBElmCRp2QB23b7Mpk0w==">
            <nameID aor=sip:alice@atlanta.com>
             <name xml:lang="it">Alice</name>
            </nameID>
          </participant>
          <participantsessionassoc
             participant_id="srfBElmCRp2QB23b7Mpk0w=="
             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>
          <participant
              participant_id="zSfPoSvdSDCmU3A3TRDxAw==">
              <nameID aor=sip:bob@biloxy.com>
               <name xml:lang="it">Bob</name>
            </nameID>
          </participant>
          <participantsessionassoc
              participant_id="zSfPoSvdSDCmU3A3TRDxAw=="
                   session_id="hVpd7YQgRW2nD22h7q60JQ==">
             <associate-time>2010-12-16T23:41:07Z</associate-time>
          </participantsessionassoc>
          <participantstreamassoc
              participant_id="zSfPoSvdSDCmU3A3TRDxAw==">
            <send>8zc6e0lYTlWIINA6GR+3ag==</send>
            <send>EiXGlc+4TruqqoDaNE76ag==</send>
            <recv>UAAMm5GRQKSCMVvLyl4rFw==</recv>
            <recv>i1Pz3to5hGk8fuXl+PbwCw==</recv>
          </participantstreamassoc>
          <stream id="UAAMm5GRQKSCMVvLyl4rFw=="
              session_id="hVpd7YQgRW2nD22h7q60JQ==">
              <label>96</label>
          </stream>
          <stream id="i1Pz3to5hGk8fuXl+PbwCw=="
              session_id="hVpd7YQgRW2nD22h7q60JQ==">
              <label>97</label>
          </stream>
          <stream id="8zc6e0lYTlWIINA6GR+3ag=="
              session_id="zSfPoSvdSDCmU3A3TRDxAw==">
              <label>98</label>
          </stream>
          <stream id="EiXGlc+4TruqqoDaNE76ag=="
              session_id="zSfPoSvdSDCmU3A3TRDxAw==">
              <label>99</label>
          </stream>
     </recording>

3.2.2.  Example 2: Hold/resume

   Assume a call between two Participants Alice and Bob is established
   and a RS is created for recording as in example1.  This is the
   continuation of above use-case.  One of the participants Bob puts
   Alice hold and then resumes as part of the same session.  The send
   and recv XML elements of a participant is used to indicate whether a
   participant is sending not sending a particular media stream whose
   properties are represented by stream element.  The metadata  SRC sends a snapshot
   looks as below
   with only the changed XML elements.

   During hold
      F2 mid call  RE-INVITE SRC-------------------->SRS

      INVITE sip:recorder@example.com SIP/2.0
      Via: SIP/2.0/TCP src.example.com;branch=z9hG4bKdf6b622b648d9
      From: <sip:2000@example.com>;tag=35e195d2-947d-4585-946f-09839247
      To: <sip:recorder@example.com>
      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:2000@src.example.com>;+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

      <?xml version="1.0" encoding="UTF-8"?>
        <recording xmlns='urn:ietf:params:xml:ns:recording'>
          <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 during snippet, Alice with participant_id
   srfBElmCRp2QB23b7Mpk0w== only receives media streams since Alice is
   put on hold and does not
   send any media.  The same is indicated by the absence of send XML
   element.  Bob(participant_id zSfPoSvdSDCmU3A3TRDxAw==) on the other
   hand would be sending media but does not receive any media from Alice
   and so 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.

      F3 mid call  RE-INVITE SRC-------------------->SRS

      INVITE sip:recorder@example.com SIP/2.0
      Via: SIP/2.0/TCP src.example.com;branch=z9hG4bKdf6b622b648d9
      From: <sip:2000@example.com>;tag=35e195d2-947d-4585-946f-09839247
      To: <sip:recorder@example.com>
      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:2000@src.example.com>;+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

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

   Basic call between two Participants Alice and Bob is connected and
   SRC
   SRC(B2BUA as per section 3.1.1 of [RFC7245]) has sent a snapshot as
   in example 1.  Transfer is initiated by one of the
   participants(Alice).  After the transfer is completed, SRC sends a
   snapshot of the participant changes to SRS.  In this transfer
   scenario, Alice drops out after transfer is completed and Bob and
   Carol gets connected and recording of media between Bob and Carol is
   done by SRC.  There may be two cases here as described below.

   Transfer with in the same session - (.e.g.  RE-INVITE based
   transfer).  Participant Alice drops out and Carol is added to the
   same session.  No change to session/group element.  A
   participantsessassoc 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 UUID tuples which corresponds
   to Bob and Carol is sent in the snapshot from SRC to SRS.  Note that
   one half of the session ID that corresponds to Bob remains same.

     mid call  RE-INVITE SRC-------------------->SRS

     INVITE sip:recorder@example.com SIP/2.0
     Via: SIP/2.0/TCP src.example.com;branch=z9hG4bKdf6b622b648d9
     From: <sip:2000@example.com>;tag=35e195d2-947d-4585-946f-09839247
     To: <sip:recorder@example.com>
     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:2000@src.example.com>;+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

  <?xml version="1.0" encoding="UTF-8"?>
      <recording xmlns='urn:ietf:params:xml:ns:recording'>
             <datamode>partial</datamode>
              <session session_id="hVpd7YQgRW2nD22h7q60JQ==">
           <sipSessionID>3363127f0d084c10876dddd4f8e5eeb9
           ;remote=2272bb7e70fe41dba0025ae9a26d54cf</sipSessionID>
        </session>
              <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>
         <participant
            participant_id="Atnm1ZRnOC6Pm5MApkrDzQ==">
            <nameIDaor=sip:carol@example.com>
             <name xml:lang="it">Carol</name>
           </nameID>
         </participant>
         <participantsessionassoc
            participant_id="Atnm1ZRnOC6Pm5MApkrDzQ=="
            session_id="hVpd7YQgRW2nD22h7q60JQ==">
            <associate-time>2013-12-16T23:41:07Z</associate-time>
         </participantsession>
         <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>

   Transfer with 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 SRC).

   SRC first sends an optional snapshot indicating disassociation of
   participant from the old CS.  Please note this is a optional message.
   An SRC may choose to just send a INVITE with a new session element to
   implicitly indicate that the participants are now part of a different
   CS with out sending disassociation from the old CS.  Also note that
   the SRC in this example uses the same RS.  In case it decides to use
   a new RS, it will tear down the current RS using normal SIP
   procedures (BYE) with metadata as in example 4.

     mid call  RE-INVITE SRC-------------------->SRS

     INVITE sip:recorder@example.com SIP/2.0
     Via: SIP/2.0/TCP src.example.com;branch=z9hG4bKdf6b622b648d9
     From: <sip:2000@example.com>;tag=35e195d2-947d-4585-946f-09839247
     To: <sip:recorder@example.com>
     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:2000@src.example.com>;+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

          <?xml version="1.0" encoding="UTF-8"?>
      <recording xmlns='urn:ietf:params:xml:ns:recording'>
             <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==">
            <disasociate-time>2010-12-16T23:41:07Z</disassociate-time>
          </participantsessionassoc>
    </recording>

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

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

      mid call  RE-INVITE SRC-------------------->SRS

      INVITE sip:recorder@example.com SIP/2.0
      Via: SIP/2.0/TCP src.example.com;branch=z9hG4bKdf6b622b648d9
      From: <sip:2000@example.com>;tag=35e195d2-947d-4585-946f-09839247
      To: <sip:recorder@example.com>
      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:2000@src.example.com>;+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

   <?xml version="1.0" encoding="UTF-8"?>
       <recording xmlns='urn:ietf:params:xml:ns:recording'>
              <datamode>complete</datamode>
          <session session_id="bfLZ+NTFEeCNxQTuRyQBmw==">
            <start-time>2010-12-16T23:41:07Z</start-time>
            <sipSessionID>3363127f0d084c10876dddd4f8e5eeb9
            ;remote=2272bb7e70fe41dba0025ae9a26d54cf</sipSessionID>
          </session>
          <participant
              participant_id="zSfPoSvdSDCmU3A3TRDxAw==">
              <nameID aor=sip:Bob@biloxy.com/>
           </participant>
          <participantsessionassoc
              participant_id="zSfPoSvdSDCmU3A3TRDxAw=="
              session_id="bfLZ+NTFEeCNxQTuRyQBmw==">
              <associate-time>2010-12-16T23:32:03Z</associate-time>
           </participantsessionassoc>
          <participantstreamassoc
              participant_id="zSfPoSvdSDCmU3A3TRDxAw==">
            <send>8zc6e0lYTlWIINA6GR+3ag==</send>
            <send>EiXGlc+4TruqqoDaNE76ag==</send>
            <recv>60JAJm9UTvik0Ltlih/Gzw==</recv>
            <recv>AcR5FUd3Edi8cACQJy/3JQ==</recv>
          </participantstreamassoc>
          <participant
             participant_id="Atnm1ZRnOC6Pm5MApkrDzQ==">
             <nameID aor=sip:carol@example.com/>
          </participant>
          <participantsessionassoc
             participant_id="Atnm1ZRnOC6Pm5MApkrDzQ=="
             session_id="bfLZ+NTFEeCNxQTuRyQBmw==">
           <associate-time>2010-12-16T23:41:07Z</associate-time>
          </participantsessionassoc>
          <participantstreamassoc
             participant_id="Atnm1ZRnOC6Pm5MApkrDzQ==">
           <send>60JAJm9UTvik0Ltlih/Gzw==</send>
           <send>AcR5FUd3Edi8cACQJy/3JQ==</send>
           <recv>8zc6e0lYTlWIINA6GR+3ag==</recv>
           <recv>EiXGlc+4TruqqoDaNE76ag==</recv>
           </participantstreamassoc>
          <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>
     </recording>

3.2.4.  Example 4: Call disconnect

   This example shows a snapshot of metadata sent by an SRC at CS
   disconnect where the participants of CS are Alice and Bob
           SRC                                                   SRS
               |                                                     |
               |(1) BYE (metadata snapshot)   F1                     |
               |---------------------------------------------------->|
               |                            200 OK    F2             |
               |<----------------------------------------------------|

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

   BYE sip:2001@8.3.2.12:5060 sip:2001@example.com SIP/2.0
   Via: SIP/2.0/UDP 8.3.2.34:5060;branch=z9hG4bK47c8eb30 src.example.com;branch=z9hG4bK47c8eb30
   From: <sip:2000@example.com>;tag=35e195d2-947d-4585-946f-09839247
   To: <sip:recorder@example.com>
   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:2000@src.example.com>;+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'>
              <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==">
             <disasociate-time>2010-12-16T23:41:07Z</disassociate-time>
           </participantsessionassoc>
      </recording>

3.3.  Call Scenarios with SRC recording streams by mixing

   The section covers the models mentioned in the architecture document
   in section 3 of [RFC7245] where an SRC may be part of Conference
   model either as Focus or a participant in Conference.  The SRS here
   could be a SIP UA or an entity part of 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

   Basic call between two Participants Alice and Bob who are part of one
   CS.  In this use case each participant sends one Media Streams.
   Media Streams sent by each participant is received by the other
   participant.  Below is the initial snapshot sent by SRC in the INVITE
   to SRS that has complete metadata.  For the sake of simplicity only
   snippets of SIP/SDP are shown.  The SRCs records the streams of each
   participant to SRS by mixing in this example.  The SRC here could be is part
   of conference Focus model described in section 3 of [RFC7245]. [RFC7245] as a Focus
   and does mixing.  The SRC here is not a participant by itself and
   hence it does not contribute to streams.

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

      INVITE sip:recorder@example.com SIP/2.0
      Via: SIP/2.0/TCP src.example.com;branch=z9hG4bKdf6b622b648d9
      From: <sip:2000@example.com>;tag=35e195d2-947d-4585-946f-09839247
      To: <sip:recorder@example.com>
      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:2000@src.example.com>;+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'>
              <datamode>complete</datamode>
         <session session_id="hVpd7YQgRW2nD22h7q60JQ==">
            <start-time>2010-12-16T23:41:07Z</start-time>
            <sipSessionID>fa3b60f27e91441e84c55a9a0095f075
             ;remote=a358d2b81a444a8c8fb05950cef331e7</sipSessionID>
             <sipSessionID>ca718e1430474b5485a53aa5d0bea45e
             ;remote=a358d2b81a444a8c8fb05950cef331e7</sipSessionID>
         </session>
          <participant
             participant_id="srfBElmCRp2QB23b7Mpk0w==">
            <nameID aor=sip:alice@atlanta.com>
             <name xml:lang="it">Alice</name>
            </nameID>
          </participant>
          <participantsessionassoc
             participant_id="srfBElmCRp2QB23b7Mpk0w=="
             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>
          <participant
              participant_id="zSfPoSvdSDCmU3A3TRDxAw==">
              <nameID aor=sip:bob@biloxy.com>
               <name xml:lang="it">Bob</name>
            </nameID>
          </participant>
          <participantsessionassoc
              participant_id="zSfPoSvdSDCmU3A3TRDxAw=="
                   session_id="hVpd7YQgRW2nD22h7q60JQ==">
             <associate-time>2010-12-16T23:41:07Z</associate-time>
          </participantsessionassoc>
          <participantstreamassoc
              participant_id="zSfPoSvdSDCmU3A3TRDxAw==">
            <send>i1Pz3to5hGk8fuXl+PbwCw==</send>
            <recv>i1Pz3to5hGk8fuXl+PbwCw==</recv>
          </participantstreamassoc>
          <stream id="i1Pz3to5hGk8fuXl+PbwCw=="
              session_id="hVpd7YQgRW2nD22h7q60JQ==">
              <label>96</label>
          </stream>
     </recording>

   In the above example there are two participants Alice and Bob in the
   conference.  Among other things, SRC sends Session-ID in the metadata
   snapshot.  There are two Session-ID's here, one that corresponds to
   the SIP session between Alice and Conference Focus and the other for
   the SIP session between Bob and Conference Focus.  One half of both
   these Session-ID's will have the same value (which is added by the
   Focus).

3.3.2.  Example 2: Hold/resume with SRC recording by mixing streams

   Assume a call between two Participants Alice and Bob is established
   and a RS is created for recording as in example 5.  This is the
   continuation of above use-case.  One of the participants Bob puts
   Alice hold and then resumes as part of the same session.  The send
   and recv XML elements of a participant is used to indicate whether a
   participant is sending not sending a particular media stream whose
   properties are represented by stream element.  The metadata snapshot
   looks as below:

   During hold
      mid call hold   RE-INVITE SRC --------------> SRS

      INVITE sip:recorder@example.com SIP/2.0
      Via: SIP/2.0/TCP src.example.com;branch=z9hG4bKdf6b622b648d9
      From: <sip:2000@example.com>;tag=35e195d2-947d-4585-946f-09839247
      To: <sip:recorder@example.com>
      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:2000@src.example.com>;+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'>
              <datamode>partial</datamode>
          <participantstreamassoc
             participant_id="srfBElmCRp2QB23b7Mpk0w==">
              <recv>i1Pz3to5hGk8fuXl+PbwCw==</recv>
          </participantstreamassoc>
          <participantstreamassoc
              participant_id="zSfPoSvdSDCmU3A3TRDxAw==">
            <send>i1Pz3to5hGk8fuXl+PbwCw==</send>
          </participantstreamassoc>
          <stream id="i1Pz3to5hGk8fuXl+PbwCw=="
              session_id="hVpd7YQgRW2nD22h7q60JQ==">
              <label>96</label>
          </stream>
     </recording>

   During resume a snapshot shown below will be sent from SRC to SRS
           mid call resume   RE-INVITE SRC --------------> SRS

      INVITE sip:recorder@example.com SIP/2.0
      Via: SIP/2.0/TCP src.example.com;branch=z9hG4bKdf6b622b648d9
      From: <sip:2000@example.com>;tag=35e195d2-947d-4585-946f-09839247
      To: <sip:recorder@example.com>
      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:2000@src.example.com>;+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'>
              <datamode>partial</datamode>
          <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>
          <stream id="i1Pz3to5hGk8fuXl+PbwCw=="
              session_id="hVpd7YQgRW2nD22h7q60JQ==">
              <label>96</label>
          </stream>
     </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.  The below shows a snapshot sent from SRC to
   SRC in these case.  Note the SRC here can be a focus or a participant
   in the conference.  In case where the SRC is a participant it may
   learn the information required for metadata by subscribing to
   conference event package [RFC4575].  Assume Alice and Bob were in the
   conference and a third participant Carol joins, then SRC sends the
   below snapshot with the indication of new participant.

           mid call resume   RE-INVITE SRC --------------> SRS

      INVITE sip:recorder@example.com SIP/2.0
      Via: SIP/2.0/TCP src.example.com;branch=z9hG4bKdf6b622b648d9
      From: <sip:2000@example.com>;tag=35e195d2-947d-4585-946f-09839247
      To: <sip:recorder@example.com>
      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:2000@src.example.com>;+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'>
              <datamode>partial</datamode>
              <session session_id="hVpd7YQgRW2nD22h7q60JQ==">

            <sipSessionID>fa3b60f27e91441e84c55a9a0095f075
             ;remote=a358d2b81a444a8c8fb05950cef331e7</sipSessionID>
             <sipSessionID>ca718e1430474b5485a53aa5d0bea45e
             ;remote=a358d2b81a444a8c8fb05950cef331e7</sipSessionID>
             <sipSessionID>497c0f13929643b4a16858e2a3885edc
             ;remote=a358d2b81a444a8c8fb05950cef331e7</sipSessionID>
         </session>
              <participant
             participant_id="Atnm1ZRnOC6Pm5MApkrDzQ==">
             <nameIDaor=sip:carol@example.com>
              <name xml:lang="it">Carol</name>
            </nameID>
          </participant>
          <participantsessionassoc
             participant_id="Atnm1ZRnOC6Pm5MApkrDzQ=="
             session_id="hVpd7YQgRW2nD22h7q60JQ==">
             <associate-time>2013-12-16T23:41:07Z</associate-time>
          </participantsession>
          <participantstreamassoc
             participant_id="Atnm1ZRnOC6Pm5MApkrDzQ==">
             <send>i1Pz3to5hGk8fuXl+PbwCw==</send>
             <recv>i1Pz3to5hGk8fuXl+PbwCw==</recv>
          </participantstreamassoc>
     </recording>

   Assume Alice drops after some time from the conference.  SRC
   generates a new snapshot showing Alice disassociating from the
   session
           mid call resume   RE-INVITE SRC --------------> SRS

      INVITE sip:recorder@example.com SIP/2.0
      Via: SIP/2.0/TCP src.example.com;branch=z9hG4bKdf6b622b648d9
      From: <sip:2000@example.com>;tag=35e195d2-947d-4585-946f-09839247
      To: <sip:recorder@example.com>
      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:2000@src.example.com>;+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'>
              <datamode>partial</datamode>
              <session session_id="hVpd7YQgRW2nD22h7q60JQ==">
             <sipSessionID>ca718e1430474b5485a53aa5d0bea45e
             ;remote=a358d2b81a444a8c8fb05950cef331e7</sipSessionID>
             <sipSessionID>497c0f13929643b4a16858e2a3885edc
             ;remote=a358d2b81a444a8c8fb05950cef331e7</sipSessionID>
         </session>
              <participantsessionassoc
             participant_id="srfBElmCRp2QB23b7Mpk0w=="
             session_id="hVpd7YQgRW2nD22h7q60JQ==">
           <associate-time>2010-12-16T23:41:07Z</associate-time>
          </participantsessionassoc>
      </recording>

3.3.4.  Example 4: Call disconnect

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

3.4.  Call scenarios with persistent RS between SRC and SRS

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

3.4.1.  Example 1: Metadata snapshot during CS disconnect with
        persistent RS between SRC and SRS

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

   INVITE sip:2001@8.3.2.12:5060 sip:2001@example.com SIP/2.0
   Via: SIP/2.0/UDP 8.3.2.34:5060;branch=z9hG4bK47c8eb30 src.example.com;branch=z9hG4bK47c8eb30
   From: <sip:2000@example.com>;tag=35e195d2-947d-4585-946f-09839247
   To: <sip:recorder@example.com>
   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:2000@src.example.com>;+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'>
              <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==">
             <disasociate-time>2010-12-16T23:41:07Z</disassociate-time>
           </participantsessionassoc>
      </recording>

3.5.  Turrent-Case: Multiple CS into single RS with mixed stream

   In trading turret, audio mixing is done locally before forwarding floor environments, in order to minimize storage and
   recording system resources, it may be preferable to mix multiple
   concurrent calls (Communication Sessions) on different handsets/
   speakers on the same turret into a single recording server.  Sender and receiver audio session.  This
   would means media in each CS is mixed for and recorded as part of single
   media stream and multiple such CSs are recording in one Recording
   Session from a SRC to SRS.

   Lets take a example where there are two CS[CS1 and CS2].  Assume
   mixing is done in each
   communication session.  The audio of these CS and both these CS are recorded as
   part of single RS from multiple communication
   sessions a single SRC which is part of both the CS.
   There are three possibilities here:

   o  CS1 and CS2 uses the same Focus for fixing and that Focus is also mixed, or multiplexed,
      acting as SRC in each of the CS.
   o  In of the CS(say CS1), SRC is Focus and in the other CS(say CS2),
      SRC is just one of the participant of the conference.
   o  In both CS1 and CS2, SRC is just a single RTP session to participant of Conference.

   The following example shows the recording server. first possibility where CS1 and CS2
   uses the same Focus for fixing and that Focus is also acting as SRC
   in each of the CS.

      snapshot of metadata  INVITE SRC --------------> SRS

      INVITE sip:recorder@example.com SIP/2.0
      Via: SIP/2.0/TCP src.example.com;branch=z9hG4bKdf6b622b648d9
      From: <sip:2000@example.com>;tag=35e195d2-947d-4585-946f-09839247
      To: <sip:recorder@example.com>
      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
      ...
   <?xml version="1.0" encoding="UTF-8"?>
       <recording xmlns='urn:ietf:params:xml:ns:recording'>
              <datamode>complete</datamode>
           <group group_id="7+OTCyoxTmqmqyA/1weDAg==">
                  <associate-time>2010-12-16T23:41:07Z</associate-time>
          </group>
          <session session_id="hVpd7YQgRW2nD22h7q60JQ==">
             <group-ref>7+OTCyoxTmqmqyA/1weDAg==</group-ref>
            <start-time>2010-12-16T23:41:07Z</start-time>
             <sipSessionID>fa3b60f27e91441e84c55a9a0095f075
             ;remote=a358d2b81a444a8c8fb05950cef331e7</sipSessionID>
             <sipSessionID>ca718e1430474b5485a53aa5d0bea45e
             ;remote=a358d2b81a444a8c8fb05950cef331e7</sipSessionID>
             <sipSessionID>497c0f13929643b4a16858e2a3885edc
             ;remote=a358d2b81a444a8c8fb05950cef331e7</sipSessionID>
          </session>
         <session session_id="zzlafnvvjlCHllaHF6mn8kkSS==">
             <group-ref>7+OTCyoxTmqmqyA/1weDAg==</group-ref>
            <start-time>2010-12-16T23:43:07Z</start-time>
            <sipSessionID>ae10731ca50343a5aaae2dd0904a65de
            ;remote=a358d2b81a444a8c8fb05950cef331e7</sipSessionID>
            <sipSession>33c77aac7deb414cbc8c10f363fccb71
            ;remote=a358d2b81a444a8c8fb05950cef331e7</sipSessionID>
            <sipSessionID>fd6932e9e5fc489fae2d5b3779723b7e
           ;remote=a358d2b81a444a8c8fb05950cef331e7</sipSessionID>
          </session>
          <participant
             participant_id="srfBElmCRp2QB23b7Mpk0w==">
            <nameID aor=sip:ram@example.com> aor=sip:alice@atlanta.com>
             <name xml:lang="it">RamMohan R</name> xml:lang="it">Alice</name>
            </nameID>
          </participant>
          <participantsessionassoc
             participant_id="srfBElmCRp2QB23b7Mpk0w=="
             session_id="hVpd7YQgRW2nD22h7q60JQ==">
           <associate-time>2010-12-16T23:41:07Z</associate-time>
          </participantsessionassoc>
          <participantstreamassoc
             participant_id="srfBElmCRp2QB23b7Mpk0w==">
             <send>UAAMm5GRQKSCMVvLyl4rFw==</send>
             <recv>UAAMm5GRQKSCMVvLyl4rFw==</recv>
          </participantstreamassoc>
          <participant
              participant_id="zSfPoSvdSDCmU3A3TRDxAw==">
              <nameID aor=sip:partha@example.com> aor=sip:Bob@biloxy.com>
               <name xml:lang="it">Parthasarathi R</name> xml:lang="it">Bob</name>
            </nameID>
          </participant>
          <participantsessionassoc
              participant_id="zSfPoSvdSDCmU3A3TRDxAw=="
              session_id="hVpd7YQgRW2nD22h7q60JQ==">
             <associate-time>2010-12-16T23:41:07Z</associate-time>
          </participantsessionassoc>
          <participantsessionassoc
              participant_id="zSfPoSvdSDCmU3A3TRDxAw=="
              session_id="zzlafnvvjlCHllaHF6mn8kkSS==">
             <associate-time>2010-12-16T23:43:07Z</associate-time>
          </participantsessionassoc>
          <participantstreamassoc
              participant_id="zSfPoSvdSDCmU3A3TRDxAw==">
            <send>UAAMm5GRQKSCMVvLyl4rFw==</send>
            <recv>UAAMm5GRQKSCMVvLyl4rFw==</recv>
          </participantstreamassoc>
          <participant
             participant_id="EiXGlc+4TruqqoDaNE76ag==">
            <nameID aor=sip:paul@example.com> aor=sip:Carol@example.com>
             <name xml:lang="it">Paul</name> xml:lang="it">Carol</name>
            </nameID>
          </participant>
          <participantsessionassoc
              participant_id="EiXGlc+4TruqqoDaNE76ag=="
              session_id="zzlafnvvjlCHllaHF6mn8kkSS==">
             <associate-time>2010-12-16T23:43:07Z</associate-time>
          </participantsessionassoc>

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

          <stream id="UAAMm5GRQKSCMVvLyl4rFw=="
              session_id="hVpd7YQgRW2nD22h7q60JQ==">
              <label>96</label>
          </stream>
     </recording>

4.  Security Considerations

   There is no security consideration as it is informatioal informational callflow
   document.

5.  IANA Considerations

   This document has no IANA considerations

6.  Acknowledgement

   Thanks to Ofir Rath, Charles Eckel for their review comments.

7.  References
7.1.  Normative References

   [RFC3261]  Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
              A., Peterson, J., Sparks, R., Handley, M., and E.
              Schooler, "SIP: Session Initiation Protocol", RFC 3261,
              June 2002.

7.2.  Informative References

   [I-D.ietf-siprec-metadata]
              R, R., Ravindran, P., and P. Kyzivat, "Session Initiation
              Protocol (SIP) Recording Metadata",
              draft-ietf-siprec-metadata-15
              draft-ietf-siprec-metadata-17 (work in progress),
              February 2014. 2015.

   [RFC7245]  Hutton, A., Portman, L., Jain, R., and K. Rehor, "An
              Architecture for Media Recording Using the Session
              Initiation Protocol", RFC 7245, May 2014.

   [RFC4575]  Rosenberg, J., Schulzrinne, H., and O. Levin, "A Session
              Initiation Protocol (SIP) Event Package for Conference
              State", RFC 4575, August 2006.

   [RFC4353]  Rosenberg, J., "A Framework for Conferencing with the
              Session Initiation Protocol (SIP)", RFC 4353,
              February 2006.

   [RFC6230]  Boulton, C., Melanchuk, T., and S. McGlashan, "Media
              Control Channel Framework", RFC 6230, May 2011.

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: rmohanr@cisco.com
   Parthasarathi Ravindran
   Nokia Networks
   Bangalore, Karnataka
   India

   Email: partha@parthasarathi.co.in

   Paul Kyzivat
   Huawei
   Hudson, MA
   USA

   Email: pkyzivat@alum.mit.edu