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Versions: (draft-ram-siprec-metadata) 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 RFC 7865

SIPREC                                           Ram Mohan. Ravindranath
Internet-Draft                                       Cisco Systems, Inc.
Intended status: Standards Track                Parthasarathi. Ravindran
Expires: August 15, 2014                    Nokia Solutions and Networks
                                                           Paul. Kyzivat
                                                                  Huawei
                                                       February 11, 2014


          Session Initiation Protocol (SIP) Recording Metadata
                     draft-ietf-siprec-metadata-15

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 describes the metadata model as
   viewed by Session Recording Server(SRS) and the Recording metadata
   format.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on August 15, 2014.

Copyright Notice

   Copyright (c) 2014 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



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   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.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  4
   3.  Definitions  . . . . . . . . . . . . . . . . . . . . . . . . .  4
   4.  Metadata Model . . . . . . . . . . . . . . . . . . . . . . . .  5
   5.  Recording Metadata Format  . . . . . . . . . . . . . . . . . .  6
     5.1.  XML data format  . . . . . . . . . . . . . . . . . . . . .  6
       5.1.1.  Namespace  . . . . . . . . . . . . . . . . . . . . . .  7
       5.1.2.  recording  . . . . . . . . . . . . . . . . . . . . . .  7
   6.  Recording Metadata classes . . . . . . . . . . . . . . . . . .  7
     6.1.  Recording Session  . . . . . . . . . . . . . . . . . . . .  8
       6.1.1.  Attributes . . . . . . . . . . . . . . . . . . . . . .  8
       6.1.2.  Linkages . . . . . . . . . . . . . . . . . . . . . . .  8
       6.1.3.  XML element  . . . . . . . . . . . . . . . . . . . . .  8
     6.2.  Communication Session Group  . . . . . . . . . . . . . . .  9
       6.2.1.  Attributes . . . . . . . . . . . . . . . . . . . . . .  9
       6.2.2.  Linkages . . . . . . . . . . . . . . . . . . . . . . .  9
       6.2.3.  XML element  . . . . . . . . . . . . . . . . . . . . . 10
     6.3.  Communication Session  . . . . . . . . . . . . . . . . . . 10
       6.3.1.  Attributes . . . . . . . . . . . . . . . . . . . . . . 11
       6.3.2.  Linkages . . . . . . . . . . . . . . . . . . . . . . . 11
       6.3.3.  XML element  . . . . . . . . . . . . . . . . . . . . . 12
     6.4.  CSRSAssociation  . . . . . . . . . . . . . . . . . . . . . 12
       6.4.1.  Attributes . . . . . . . . . . . . . . . . . . . . . . 13
       6.4.2.  Linkages . . . . . . . . . . . . . . . . . . . . . . . 13
       6.4.3.  XML element  . . . . . . . . . . . . . . . . . . . . . 13
     6.5.  Participant  . . . . . . . . . . . . . . . . . . . . . . . 13
       6.5.1.  Attributes . . . . . . . . . . . . . . . . . . . . . . 14
       6.5.2.  Linkages . . . . . . . . . . . . . . . . . . . . . . . 14
       6.5.3.  XML element  . . . . . . . . . . . . . . . . . . . . . 14
     6.6.  ParticipantCSAssociation . . . . . . . . . . . . . . . . . 15
       6.6.1.  Attributes . . . . . . . . . . . . . . . . . . . . . . 15
       6.6.2.  Linkages . . . . . . . . . . . . . . . . . . . . . . . 16
       6.6.3.  XML element  . . . . . . . . . . . . . . . . . . . . . 16
     6.7.  Media Stream . . . . . . . . . . . . . . . . . . . . . . . 16
       6.7.1.  Attributes . . . . . . . . . . . . . . . . . . . . . . 17
       6.7.2.  Linkages . . . . . . . . . . . . . . . . . . . . . . . 17
       6.7.3.  XML element  . . . . . . . . . . . . . . . . . . . . . 17
     6.8.  ParticipantStream Association  . . . . . . . . . . . . . . 18



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       6.8.1.  Attributes . . . . . . . . . . . . . . . . . . . . . . 18
       6.8.2.  Linkages . . . . . . . . . . . . . . . . . . . . . . . 18
       6.8.3.  XML element  . . . . . . . . . . . . . . . . . . . . . 19
     6.9.  associate-time/disassociate-time . . . . . . . . . . . . . 19
     6.10. Unique ID format . . . . . . . . . . . . . . . . . . . . . 19
     6.11. Metadata version Indicator . . . . . . . . . . . . . . . . 19
   7.  SIP Recording Metadata Example . . . . . . . . . . . . . . . . 20
     7.1.  Complete SIP Recording Metadata Example  . . . . . . . . . 20
     7.2.  Partial Update of Recording metadata XML body  . . . . . . 22
   8.  XML Schema definition for Recording metadata . . . . . . . . . 22
   9.  Security Considerations  . . . . . . . . . . . . . . . . . . . 26
     9.1.  Connection Security  . . . . . . . . . . . . . . . . . . . 26
   10. IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 27
     10.1. SIP recording metadata Schema Registration . . . . . . . . 27
   11. Acknowledgement  . . . . . . . . . . . . . . . . . . . . . . . 27
   12. References . . . . . . . . . . . . . . . . . . . . . . . . . . 28
     12.1. Normative References . . . . . . . . . . . . . . . . . . . 28
     12.2. Informative References . . . . . . . . . . . . . . . . . . 28
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 29
































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1.  Introduction

   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 focuses on the Recording metadata
   which describes the communication session.  The document describes a
   metadata model as viewed by Session Recording Server and the
   Recording metadata format, the requirements for which are described
   in [RFC6341] and the architecture for which is described in
   [I-D.ietf-siprec-architecture].


2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].  This
   document only uses these key words when referencing normative
   statements in existing RFCs."


3.  Definitions

   Metadata Model: An abstract representation of metadata using a
   Unified Modelling Language(UML) class diagram.

   Metadata classes: Each block in the model represents a class.  A
   class is a construct that is used as a blueprint to create
   instances(called objects) of itself.  The description of each class
   also has representation of its attributes in a second compartment
   below the class name.

   Attributes: Attributes represent the elements listed in each of the
   classes.  The attributes of a class are listed in the second
   compartment below the class name.  Each instance of class conveys
   values for these attributes which adds to the recording's Metadata.

   Linkages: Linkages represent the relationship between the classes in
   the model.  Each represents a logical connection between classes(or
   objects) in class diagrams/ object diagrams.  The linkages used in
   the Metadata model of this document are associations.







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4.  Metadata Model

   Metadata is the information that describes recorded media and the CS
   to which they relate.  The diagram below shows a model for Metadata
   as viewed by a Session Recording Server (SRS).




             +-------------------------------+
             |    Recording Session (RS)     |
             +-------------------------------+
                   |1..*           | 1..*
                   |               |
                   |               | 0..*
                   |        +-----------------+
   +------------+  |        | Communication   |
   | CSRS       |  |        |  Session (CS)   |
   | Association|--+        |    Group        |
   |            |  |        +-----------------+
   +------------+  |              | 0..1
                   |              |
                   |0..*          | 1..*
   +-------------------------------+
   |   Communication Session (CS)  |
   |                               |
   +-------------------------------+
         | 1..*                   |0..1
   +-----+                        |
   |     | 0..*                   |0..*
   | +-------------+ receives +----------------+
   | | Participant |----------|  Media Streams |
   | |             |0..*  0..*|                |
   | |             |          |                |
   | |             |          |                |
   | |             |  sends   |                |
   | |             |----------|                |
   | |             |1.*   0..*|                |
   | +-------------+          +----------------+
   |        |                        |
   |        |                        |
   |        +------------------------+------------+
   |                                              |
   |                                              |
   |           +------------------+    +----------------------+
   |           |ParticipantCS     |    |  ParticipantStream   |
   +-----------|  Association     |    |    Association       |
               |                  |    |                      |



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               +------------------+    +----------------------+



   The Metadata model is a class diagram in Unified Modelling
   Language(UML).  The model describes the structure of a metadata in
   general by showing the classes, their attributes, and the
   relationships among the classes.  Each block in the model above
   represents a class.  The linkages between the classes represents the
   relationships which can be associations or Composition.  The metadata
   is conveyed from SRC to SRS.

   The model allows the capture of a snapshot of a recording's Metadata
   at a given instant in time.  Metadata changes to reflect changes in
   what is being recorded.  For example, if a participant joins a
   conference, then the SRC sends the SRS a snapshot of metadata having
   that participant information (with attributes like name/AoR pair and
   associate-time.)

   Some of the metadata is not required to be conveyed explicitly from
   the SRC to the SRS, if it can be obtained contextually by the
   SRS(e.g., from SIP or SDP signalling).


5.  Recording Metadata Format

   This section gives an overview of the Recording Metadata Format.
   Some data from the metadata model is assumed to be made available to
   the SRS through Session Description Protocol (SDP)[RFC4566], and
   therefore this data is not represented in the XML document format
   specified in this document.  SDP attributes describe different media
   formats like audio, video.  The other metadata attributes, such as
   participant details, are represented in a new Recording specific XML
   document of type 'application/rs-metadata+xml'.  The SDP label
   attribute [RFC4574] provides an identifier by which a metadata XML
   document can refer to a specific media description in the SDP sent
   from the SRC to the SRS.

   The XML document format can be used to represent either the complete
   metadata or a partial update to the metadata.  The latter includes
   only elements that have changed compared to the previously reported
   metadata.

5.1.  XML data format

   Every recording metadata XML document MUST contain a <recording>
   element.  The <recording> element acts as a container for all other
   elements in this XML document.



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   A recording object is a XML document.  It MUST have the XML
   declaration and it SHOULD contain an encoding declaration in the XML
   declaration, e.g., "<?xml version='1.0' encoding='UTF-8'?>".  If the
   charset parameter of the MIME content type declaration is present and
   it is different from the encoding declaration, the charset parameter
   takes precedence.

   Every application conforming to this specification MUST accept the
   UTF-8 character encoding to ensure the minimal interoperability.

   Syntax and semantic errors in an XML document should be reported to
   the originator using application specific mechanisms.

5.1.1.  Namespace

   The namespace URI for elements defined by this specification is a
   Uniform Resource Namespace (URN) [RFC2141], using the namespace
   identifier 'ietf' defined by [RFC2648] and extended by [RFC3688].

   The URN is: urn:ietf:params:xml:ns:recording

5.1.2.  recording

   The <recording> element MUST contain an xmlns namespace attribute
   with value as urn:ietf:params:xml:ns:recording.  One recording
   element MUST be present in every recording metadata XML document.

   A recording element MAY contain a <dataMode> element indicating
   whether the XML document is a complete document or a partial update.
   If no <dataMode> element is present then the default value is
   "complete".


6.  Recording Metadata classes

   This section describes each class of the metadata model, and the
   attributes of each class.  This section also describes how different
   classes are linked and the XML element for each of them.













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6.1.  Recording Session


   +-------------------------------+
   | Recording Session (RS)        |
   +-------------------------------+
   |                               |
   |     Start/End Time            |
   |                               |
   |                               |
   |                               |
   +-------------------------------+
         |1..*            | 1..*
         |                |
         |0..*            | 0..*
    Communication    Communication
    Session          Session Group(CS Group)


   Each instance of a Recording Session class (namely the Recording
   Session Object) represents a SIP session created between an SRC and
   SRS for the purpose of recording a Communication Session.

6.1.1.  Attributes

   A Recording Session class has the following attributes:
   o  Start/End Time - Represents the Start/End time of a Recording
      Session object.

6.1.2.  Linkages

   Each instance of Recording Session has:

   o  Zero or more instances of Communication Session Group (CSG).
   o  Zero or more instances of Communication Session objects.

   CSs and CSGs are optional to accommodate persistent recording, where
   there may sometimes be none.

6.1.3.  XML element

   A Recording Session object is represented by a <recording> XML
   element.  That in turn relies on the SIP/SDP session with which the
   XML document is associated to provide some of the attributes of the
   Recording Session element.

   Start and End time value are derivable from Date header(if present in
   SIP message) in RS.  In cases where Date header is not present,



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   Start/End time are derivable from the time at which SRS receives the
   notification of SIP message to setup RS / disconnect RS.

6.2.  Communication Session Group


    Recording Session (RS)
              | 1..*
              |
              | 0..*
   +-------------------------------+
   | Communication Session         |
   |     Group                     |
   +-------------------------------+
   |  Unique-ID                    |
   |  associate-time               |
   |  disassociate-time            |
   |                               |
   +-------------------------------+
              | 0..1
              |
              | 1..*
    Communication Session (CS)


   One instance of a Communication Session Group class (namely the
   Communication Session Group object) provides association or linking
   of Communication Sessions.

6.2.1.  Attributes

   A CS Group has the following attributes:
   o  Unique-ID - This Unique-ID is to group different CSs that are
      related.  SRC (or SRS) is responsible for ensuring the uniqueness
      of Unique-ID in case multiple SRC interacts with the same SRS.
      The mechanism by which SRC groups the CS is outside the scope of
      SIPREC.
   o  Associate-time - Associate-time for CS-Group shall be calculated
      by SRC as the time when a grouping is formed.  The rules that
      determine how a grouping of different Communication Session
      objects is done by SRC is outside the scope of SIPREC.
   o  Disassociate-time - Disassociate-time for CS-Group shall be
      calculated by SRC as the time when the grouping ends

6.2.2.  Linkages

   The linkages between Communication Session Group class and other
   classes are associations.  A communication Session Group is



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   associated with RS and CS in the following manner:

   o  There are one or more Recording Session objects per Communication
      Session Group.
   o  Each Communication Session Group object has to be associated with
      one or more RS [Here each RS can be setup by the potentially
      different SRCs]
   o  There are one or more Communication Sessions per CS Group [e.g.
      Consult Transfer]

6.2.3.  XML element

   The <group> element is an optional element provides the information
   about the communication session group

   Each communication session group (CSG)object is represented using one
   group element.  Each <group> element has a unique 'group-id'
   attribute which uniquely identifies the CSG.

6.3.  Communication Session



   Recording              Communication
   Session            Session Group(CS Group)
      |1..*                  | 0..1
      |                      |
      |0..*                  | 1..*
   +-------------------------------+
   |   Communication Session (CS)  |
   |                               |
   +-------------------------------+
   |   CS Identifier               |
   |   Termination Reason          |
   |   Start-time                  |
   |   Stop-time                   |
   +-------------------------------+
      |                      |
      | 0..*                 |0..1
      |                      |
      | 0..*                 |0..*
   Participant              Media Stream



   A Communication Session class and its object in the metadata model
   represents a Communication Session and its properties needed as seen
   by the SRC.



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6.3.1.  Attributes

   A communication Session class has the following attributes:

   o  Termination Reason - This represents the reason why a CS was
      terminated.  The communication session MAY contain a Call
      Termination Reason.  This MAY be derived from SIP Reason header
      [RFC3326] of CS.
   o  CS Identifier - This attribute is used to uniquely identify a CS.
   o  Start-time - This optional attribute represents start time of CS
      as seen by SRC
   o  Stop-time - This optional attribute represents stop time of CS as
      seen by SRC

   This document does not specify attributes relating to what should
   happen to a recording of a CS after it has been delivered to the SRS.
   (E.g., how long to retain the recording, what access controls to
   apply.)  The SRS is assumed to behave in accordance with policy.  The
   ability for the SRC to influence this policy is outside the scope of
   this document.  However if there are implementations where SRC has
   enough information, this could be sent as Extension Data attached to
   the CS

6.3.2.  Linkages

   A Communication Session is linked to CS-Group, Participant, Media
   Stream and Recording Session classes using the association
   relationship.  Association between CS and Participant allows:

   o  CS to have zero or more participants
   o  Participant is associated with zero or more CSs.  This includes
      participants who are not directly part of any CS.  An example of
      such a case is participants in a premixed media stream.  The SRC
      may have knowledge of such Participants, yet not have any
      signaling relationship with them.  This might arise if one
      participant in CS is a conference focus.  To summarize, even if
      the SRC does not have direct signalling relationships with all
      participants in a CS, it should nevertheless create a Participant
      object for each participant that it knows about.
   o  The model also allows participants in CS that are not participants
      in the media.  An example is the identity of a 3pcc controller
      that has initiated a CS to two or more participants of the CS.
      Another example is the identity of a conference focus.  Of course
      a focus is probably in the media, but since it may only be there
      as a mixer, it may not report itself as a participant in any of
      the media streams.

   Association between CS and Media Stream allows:



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   o  A CS to have zero or more Streams
   o  A stream can be associated with at most one CS.  Stream in
      persistent RS is not required to be associated with any CS before
      CS is created and hence the zero association is allowed.

   Association between CS and RS allows:

   o  Each instance of RS has Zero or more instances of Communication
      Session objects.
   o  Each CS has to be associated with one more RS [ Here each RS can
      be potentially setup by different SRCs]

6.3.3.  XML element

   The <session> element provides the information about the
   Communication Session

   Each communication session(CS) object is represented by one session
   element.  Each session element has unique 'session_id' attribute
   which helps to uniquely identify the CS.

   The XML <reason> element MAY be included in metadata to represent a
   CS Termination Reason.  There MAY be multiple instances of the XML
   <reason> element inside a session element.  The <reason> XML element
   has 'protocol' as an attribute, which indicates the protocol from
   which the reason string is derived.  The default value for protocol
   attribute is "SIP".  The <reason> element can be derived from a SIP
   Reason header in the CS.

   A <group-ref> element MAY be present to indicate the group to which
   the enclosing session belongs.

6.4.  CSRSAssociation



                        1..*            0..*
      Recording                             Communication
       Session        ----------+---------- Session
                                |
                                |
                                |
                      +-------------------+
                      | CSRSAssociation   |
                      +-------------------+
                      | Association-Time  |
                      | Disassociaton-Time|
                      +-------------------+



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   The CSRS Association class describes the association of a CS to an RS
   for a period of time.  A single CS may be associated with different
   RSs (perhaps by different SRCs) and may be associated and dissociated
   several times.

6.4.1.  Attributes

   CSRS association class has the following attributes:

   o  Associate-time - associate-time is calculated by SRC as the time
      it sees a CS is associated to a RS
   o  Disassociate-time- Disassociate-time is calculated by SRC as the
      time it see a CS disassociate from a RS.

6.4.2.  Linkages

   CSRS association class is linked to CS and RS classes.

6.4.3.  XML element

   The <sessionrecordingassoc> XML element represents the CSRS
   association object.  The 'session_id' attribute is used to uniquely
   identify this element and link with a specific session.  The
   recording object is implicitly defined by the enclosing <recording>
   element.

6.5.  Participant


    Communication Session (CS)
              | 0..*
              |
              | 0..*
   +-------------------------------+
   |          Participant          |
   |                               |
   +-------------------------------+
   |  AoR / Name Pair list         |
   |                               |
   |                               |
   +-------------------------------+
           | 0..*       1..*|
   receives|                |sends
           | 0..*       0..*|
             Media Stream






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   A Participant class and its objects has information about a device
   that is part of a CS and/or contributes/consumes media stream(s)
   belonging to a CS.

6.5.1.  Attributes

   Participant has a single defined attribute:

   o  AoR / Name pair list - This attribute is a list of Name/AoR
      tuples.  An AoR MAY be a SIP/SIPS/TEL URI.  Name represents
      Participant name(SIP display name) or dialed number (DN) (when
      known).  Multiple tuples are allowed for cases where a participant
      has more than one AoR.  (For example a P-Asserted-identity header
      [RFC3325] can have both SIP and TEL URIs.)

   This document does not specify other attributes relating to
   participant e.g.  Participant Role, Participant type.  An SRC which
   has information of these attributes can indicate the same as part of
   extension data to Participant from SRC to SRS.

6.5.2.  Linkages

   The participant class is linked to MS and CS class using association
   relationship.  The association between participant and Media Stream
   allows:

   o  Participant to receive zero or more media streams
   o  Participant to send zero or more media streams.  (Same participant
      provides multiple streams e.g. audio and video)
   o  Media stream to be received by zero or more participants.  Its
      possible, though perhaps unlikely, that a stream is generated but
      sent only to the SRC and SRS, not to any participant.  E.g.  In
      conferencing where all participants are on hold and the SRC is
      collocated with the focus.  Also a media stream may be received by
      multiple participants (e.g.  Whisper calls, side conversations).
   o  Media stream to be sent by one or more participants (pre-mixed
      streams).

   Example of a case where a participant receives zero or more streams -
   a supervisor may have side conversation with agent, while agent
   converses with customer.

6.5.3.  XML element

   A <participant> element represents a Participant object.

   Participant MUST have a NameID complex element which contains AoR as
   attribute and Name as element.  AOR element is SIP/SIPS URI FQDN or



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   IP address which represents the user. name is an optional element to
   represent display name.

   Each participant has a unique 'participant_id' attribute.  This MUST
   be used for all references to a participant within a CSG, and MAY be
   used to reference the same participant more globally.  (The decision
   to use a participant_id across multiple CSGs or recording sessions is
   at the discretion of the implementer.)

6.6.  ParticipantCSAssociation



                        1..*            0..*
      Communication
       Session        ----------+---------- Participant
                                |
                                |
                                |
                      +-------------------+
                      | ParticipantCS     |
                      | Association       |
                      +-------------------+
                      | Capabilities      |
                      | Association-Time  |
                      | Disassociaton-Time|
                      +-------------------+


   The Participant CS Association class describes the association of a
   Participant to an CS for a period of time.  A participant may be
   associated and dissociated from a CS several times.  (For example,
   connecting to a conference, then disconnecting, then connecting
   again.)

6.6.1.  Attributes

   ParticipantCS association class has the following attributes:

   o  Associate-time - associate-time is calculated by SRC as the time
      it sees a participant is associated to CS
   o  Disassociate-time- Disassociate-time is calculated by the SRC as
      the time it sees a participant disassociate from a CS.  It is
      possible that a given participant can have multiple associate/
      disassociate times within given communication session.
   o  Capabilities - An optional attribute describing the capabilities
      of a participant in a CS, as defined in [RFC3840].  Each
      participant may have zero or more capabilities.  A participant may



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      use different capabilities depending on the role it plays at a
      particular instance.  For example if a participant moves across
      different CSs (e.g., due to transfer) or is simultaneously present
      in different CSs its role may be different and hence the
      capability used.

6.6.2.  Linkages

   The participantCS association class is linked to participant and CS
   classes.

6.6.3.  XML element

   The <participantsessionassoc> XML element represents a participantCS
   association object.  The 'participant_id' and 'session_id' attributes
   are used to uniquely identify this element.

   NOTE: RFC 4235 encoding shall be used to represent capabilities
   attribute in XML.

6.7.  Media Stream


                                   Participant
                               | 0..*       1..*|
                       receives|                |sends
                               | 0..*       0..*|
                            +-------------------------+
                            |          Media Stream   |
                            |                         |
   Communication 0..1  0..* +-------------------------+
     Session    ------------|                         |
                            |  Media Stream Reference |
                            |  Content-type           |
                            |                         |
                            +-------------------------+



   A Media Stream class (and its objects) has the properties of media as
   seen by SRC and sent to SRS.  Different snapshots of a media stream
   object may be sent whenever there is a change in media (e.g.
   direction change like pause/resume and/or codec change and/or
   participant change.).







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6.7.1.  Attributes

   A Media Stream class has the the following attributes:

   o  Media Stream Reference - In implementations this references an
      m-line
   o  Content - The content of an MS element will be described in terms
      of value from the [RFC4796] registry.

   The metadata model should include media streams that are not being
   delivered to the SRS.  Examples include cases where SRC offered
   certain media types but SRS chooses to accept only a subset of them
   OR an SRC may not even offer a certain media type due it its
   restrictions to record

6.7.2.  Linkages

   A Media Stream is linked to participant and CS classes using the
   association relationship.  The details of association with the
   Participant are described in the Participant class section.  The
   details of association with CS is mentioned in the CS section.

6.7.3.  XML element

   The <stream> element represents a Media Stream object.  Stream
   element indicates SDP media lines associated with the session and
   participants.

   The <label> element within the <stream> element references an SDP
   "a=label" attribute that identifies an m-line within the RS SDP.
   That m-line carries the media stream from the SRC to the SRS.

   Each stream element has unique 'stream_id' attribute which helps to
   uniquely identify stream and 'session_id' attribute to associate the
   stream with specific session element.

   If the SRC wishes to convey the Content-type to the SRS, it does so
   by including an 'a=content' attribute with the m-line in the RS SDP.













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6.8.  ParticipantStream Association



   +-------------------+
   | ParticipantSteam  |
   | Association       |
   +-------------------+   +----------Participant
   | Association-Time  |   |       0..*| 1..*|
   | Disassociaton-Time|---+       recv|     |sends
   | Recv              |   |       0..*| 0..*|
   | Send              |   |           |     |
   +-------------------+   |           |     |
                           +----------Media Stream



   A ParticipantStream association class describes the association of a
   Participant to a Media Stream for a period of time, as a sender or as
   a receiver, or both.

6.8.1.  Attributes

   A participantStream association class has the following attributes:

   o  Associate-Time: This attribute indicates the time a Participant
      started contributing to a Media Stream
   o  Disassociate-Time: This attribute indicates the time a Participant
      stopped contributing to a Media Stream
   o  Recv: This attribute indicates whether a Participant is receiving
      a media stream or not.  This attribute has a value which points to
      a stream represented by its Unique_id.  The presence of this
      attribute indicates that a participant is receiving a stream
      represented by the Unique_id.  If due to changes in CS(like hold)
      the participants stops receiving a stream, a snapshot MUST be sent
      from SRC to SRS with no Recv element for that stream.
   o  Send: This attribute indicates whether a participant is
      contributing to a stream or not.  This attribute has a value which
      points to stream represented by its unique_id.  The presence of
      this attribute indicates that a participant is contributing to a
      stream represented by the Unique_id.  If due to changes in CS if a
      participant stops contributing to a stream, a snapshot MUST be
      sent from SRC to SRS with no Send element for that stream.

6.8.2.  Linkages

   The participantStream association class is linked to participant and
   Stream classes.



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6.8.3.  XML element

   The <participantstreamassoc> XML element represents the participant
   to stream association object.  This XML element is used to represent
   a snapshot of a participant association with a stream.  The send and
   recv XML elements MUST be used to indicate whether a participant is
   contributing to a stream or receiving a stream.  There MAY be
   multiple instances of the send and recv XML elements inside a
   particpantstreamassoc element.  If a metadata snapshot is sent with a
   participantstreamassoc that does not have any send and recv elements,
   it means that participant is neither contributing to any streams nor
   receiving any streams.

6.9.  associate-time/disassociate-time

   The XML <associate-time> and <disassociate-time> elements contain
   strings indicating the date and time of the status change of this
   tuple.  The value of these elements MUST follow the IMPP datetime
   format [RFC3339].  Timestamps that contain 'T' or 'Z' MUST use the
   capitalized forms.  At a time, any of the time tuple associate-time
   or disassociate-time MAY exist in the element namely group, session,
   participant and not both timestamp at the same time.

   As a security measure, the timestamp element SHOULD be included in
   all tuples unless the exact time of the status change cannot be
   determined.

6.10.  Unique ID format

   A Unique id is generated in two steps:
   o  the UUID is created using [RFC4122]
   o  the UUID is encoded using base64 as defined in [RFC4648]

   The above mentioned unique-id mechanism SHOULD be used for each
   metadata element.  Multiple SRCs can refer to the same element/UUID
   (how each SRC learns the UUID here is out of scope of SIPREC)

6.11.  Metadata version Indicator

   This section defines a version indicator for metadata XML.

   This version value allows the SRS to know the exact metadata XML
   schema used by the SRC.  This document describes version 1.
   Implementations may not interoperate if the version implemented by
   the sender is not known by the receiver.  No negotiation of versions
   is provided.  There is no significance to the version number although
   documents which update or obsolete this document (possibly including
   drafts of such documents) should include a higher version number if



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   the metadata XML schema changes.


7.  SIP Recording Metadata Example

7.1.  Complete SIP Recording Metadata Example

   The following example provides all the tuples involved in Recording
   Metadata XML body.


 <?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>
              <!-- Standardized extension -->
             <call-center xmlns='urn:ietf:params:xml:ns:callcenter'>
               <supervisor>sip:alice@atlanta.com</supervisor>
             </call-center>
             <mydata xmlns='http://example.com/my'>
               <structure>FOO!</structure>
               <whatever>bar</whatever>
             </mydata>
           </group>
           <session session_id="hVpd7YQgRW2nD22h7q60JQ==">
             <group-ref>7+OTCyoxTmqmqyA/1weDAg==
             </group-ref>
              <!-- Standardized extension -->
              <uniqueid>FaXHlc+3WruaroDaNE87am==</uniqueid>
             <structure>FOO!</structure>
             <whatever>bar</whatever>
           </session>
           <sessionrecordingassoc session_id="hVpd7YQgRW2nD22h7q60JQ==">
           <associate-time>2010-12-16T23:41:07Z</associate-time>
           </sessionrecordingassoc>
           <participant
              participant_id="srfBElmCRp2QB23b7Mpk0w==">
              <nameID aor=sip:bob@biloxi.com>
                            <name xml:lang="it">Bob B</name>
                           </nameID>
              <!-- Standardized extension -->
             <structure>FOO!</structure>
             <whatever>bar</whatever>
           </participant>
           <participantsessionassoc
              participant_id="srfBElmCRp2QB23b7Mpk0w=="
              session_id="hVpd7YQgRW2nD22h7q60JQ==">



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            <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:Paul@biloxy.com>
                            <name xml:lang="it">Paul</name>
                           </nameID>
               <!-- Standardized extension -->
             <structure>FOO!</structure>
             <whatever>bar</whatever>
           </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 stream_id="UAAMm5GRQKSCMVvLyl4rFw=="
               session 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>
      </recording>




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                  SIP Recording Metadata Example XML body

7.2.  Partial Update of Recording metadata XML body

   The following example provides partial update in Recording Metadata
   XML body for the above example.  The example has a snapshot that
   carries the disassociate-time for a participant from a session.


    <?xml version="1.0" encoding="UTF-8"?>
       <recording xmlns='urn:ietf:params:xml:ns:recording:1'>
         <dataMode>partial</dataMode>
         <participant
            participant_id="srfBElmCRp2QB23b7Mpk0w==">
            <name ID=sip:bob@biloxi.com>
                      <name xml:lang="it">Bob R</name>
                    </nameID>
             <structure>FOO!</structure>
             <whatever>bar</whatever>
         </participant>
         <participantsessionassoc
               participant_id="srfBElmCRp2QB23b7Mpk0w=="
               session_id="hVpd7YQgRW2nD22h7q60JQ==">
             <disassociate-time>2010-12-16T23:41:07Z</disassociate-time>
          </participantsessionassoc>
       </recording>


             Partial update of SIP Recording Example XML body


8.  XML Schema definition for Recording metadata

   This section defines XML schema for Recording metadata document


<?xml version="1.0" encoding="UTF-8"?>
   <xs:schema targetNamespace="urn:ietf:params:xml:ns:recording:1"
      xmlns:xs="http://www.w3.org/2001/XMLSchema"
      xmlns:tns="urn:ietf:params:xml:ns:recording"
      elementFormDefault="qualified"
      attributeFormDefault="unqualified">
     <!-- This import brings in the XML language attribute xml:lang-->
     <xs:import namespace="http://www.w3.org/XML/1998/namespace"/>
     <xs:element name="recording" type="tns:recording"/>
     <xs:complexType name="recording">
         <xs:sequence>
             <xs:element name="datamode" type="tns:dataMode"



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                  minOccurs="0"/>
           <xs:element name="group" type="tns:group"
                  minOccurs="0" maxOccurs="unbounded"/>
             <xs:element name="session" type="tns:session"
                  minOccurs="0" maxOccurs="unbounded"/>
             <xs:element name="participant" type="tns:participant"
                  minOccurs="0" maxOccurs="unbounded"/>
             <xs:element name="stream" type="tns:stream"
                 minOccurs="0" maxOccurs="unbounded"/>
            <xs:element name="sessionrecordingassoc"
                 type="tns:sessionrecordingassoc"
                 minOccurs="0" maxOccurs="unbounded"/>
            <xs:element name="participantsessionassoc"
                 type="tns:participantsessionassoc"
                 minOccurs="0" maxOccurs="unbounded"/>
            <xs:element name="participantstreamassoc"
                 type="tns:participantstreamassoc"
                 minOccurs="0" maxOccurs="unbounded"/>
            <xs:any namespace='##other'
                     minOccurs='0'
                     maxOccurs='unbounded'
                     processContents='lax'/>
         </xs:sequence>
     </xs:complexType>
     <xs:complexType name="group">
         <xs:sequence>
           <xs:element name="associate-time" type="xs:dateTime"
              minOccurs="0"/>
           <xs:element name="disassociate-time" type="xs:dateTime"
              minOccurs="0"/>
          <xs:any namespace='##other'
                     minOccurs='0'
                     maxOccurs='unbounded'
                     processContents='lax'/>
         </xs:sequence>
         <xs:attribute name="group_id" type="xs:base64Binary"
              use="required"/>
     </xs:complexType>

     <xs:complexType name="session">
         <xs:sequence>
           <xs:element name="reason" type="tns:reason" minOccurs="0"
                   maxOccurs="unbounded"/>
           <xs:element name="group-ref" type="xs:base64Binary"
                  minOccurs="0" maxOccurs="1"/>
           <xs:element name="start-time" type="xs:dateTime"
                  minOccurs="0" maxOccurs="1"/>
           <xs:element name="stop-time" type="xs:dateTime"



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                  minOccurs="0" maxOccurs="1"/>
              <xs:any namespace='##other'
                     minOccurs='0'
                     maxOccurs='unbounded'
                     processContents='lax'/>
         </xs:sequence>
         <xs:attribute name="session_id" type="xs:base64Binary"
              use="required"/>
     </xs:complexType>
     <xs:complexType name="sessionrecordingassoc">
         <xs:sequence>
           <xs:element name="associate-time" type="xs:dateTime"
                  minOccurs="0"/>
           <xs:element name="disassociate-time" type="xs:dateTime"
                  minOccurs="0"/>
           <xs:any namespace='##other'
                     minOccurs='0'
                     maxOccurs='unbounded'
                     processContents='lax'/>
         </xs:sequence>
         <xs:attribute name="session_id" type="xs:base64Binary"
              use="required"/>
     </xs:complexType>
     <xs:complexType name="participant">
         <xs:sequence>
             <xs:element name="nameID" type="tns:nameID"
                     maxOccurs='unbounded'/>
             <xs:element name="param" minOccurs="0" maxOccurs="unbounded">
               <xs:complexType>
                  <xs:attribute name="pname" type="xs:string" use="required"/>
                  <xs:attribute name="pval" type="xs:string" use="required"/>
                </xs:complexType>
             </xs:element>
          <xs:any namespace='##other'
                     minOccurs='0'
                     maxOccurs='unbounded'
                     processContents='lax'/>
         </xs:sequence>
         <xs:attribute name="participant_id" type="xs:base64Binary"
              use="required"/>
  </xs:complexType>
     <xs:complexType name="participantsessionassoc">
         <xs:sequence>
         <xs:element name="associate-time" type="xs:dateTime"
                  minOccurs="0"/>
         <xs:element name="disassociate-time" type="xs:dateTime"
                  minOccurs="0"/>
           <xs:any namespace='##other'



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                     minOccurs='0'
                     maxOccurs='unbounded'
                     processContents='lax'/>
         </xs:sequence>
         <xs:attribute name="participant_id" type="xs:base64Binary"
              use="required"/>
         <xs:attribute name="session_id" type="xs:base64Binary"
              use="required"/>
     </xs:complexType>
     <xs:complexType name="participantstreamassoc">
         <xs:sequence>
             <xs:element name="send" type="xs:base64Binary"
               minOccurs="0" maxOccurs="unbounded"/>
             <xs:element name="recv" type="xs:base64Binary"
               minOccurs="0" maxOccurs="unbounded"/>
               <xs:element name="associate-time" type="xs:dateTime"
                  minOccurs="0"/>
            <xs:element name="disassociate-time" type="xs:dateTime"
                  minOccurs="0"/>
               <xs:any namespace='##other'
                     minOccurs='0'
                     maxOccurs='unbounded'
                     processContents='lax'/>
         </xs:sequence>
         <xs:attribute name="participant_id" type="xs:base64Binary"
              use="required"/>
     </xs:complexType>
     <xs:complexType name="stream">
         <xs:sequence>
           <xs:element name="label" type="xs:string"
               minOccurs="0" maxOccurs="1"/>
            <xs:any namespace='##other'
                     minOccurs='0'
                     maxOccurs='unbounded'
                     processContents='lax'/>
         </xs:sequence>
         <xs:attribute name="stream_id" type="xs:base64Binary"
              use="required"/>
         <xs:attribute name="session_id" type="xs:base64Binary"/>
     </xs:complexType>
       <xs:simpleType name="dataMode">
           <xs:restriction base="xs:string">
              <xs:enumeration value="complete"/>
                      <xs:enumeration value="partial"/>
           </xs:restriction>
     </xs:simpleType>
     <xs:complexType name="nameID">
      <xs:sequence>



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         <xs:element name="name" type ="tns:name" minOccurs="0"
                            maxOccurs="1"/>
      </xs:sequence>
      <xs:attribute name="aor" type="xs:anyURI" use="required"/>
    </xs:complexType>
   <xs:complexType name="name">
   <xs:simpleContent>
          <xs:extension base="xs:string">
           <xs:attribute ref="xml:lang" use="optional"/>
          </xs:extension>
         </xs:simpleContent>
    </xs:complexType>
    <xs:complexType name="reason">
      <xs:simpleContent>
       <xs:extension base="xs:string">
          <xs:attribute type="xs:short" name="cause" use="required"/>
          <xs:attribute type="xs:string" name="protocol" default="SIP"/>
       </xs:extension>
      </xs:simpleContent>
    </xs:complexType>
</xs:schema>



9.  Security Considerations

   The metadata information sent from SRC to SRS MAY reveal sensitive
   information about different participants in a session.  For this
   reason, it is RECOMMENDED that a SRC use a strong means for
   authentication and metadata information protection and that it apply
   comprehensive authorization rules when using the metadata format
   defined in this document.  The below section discusses each of these
   aspects in more detail.

9.1.  Connection Security

   It is RECOMMENDED that a SRC authenticate the SRS using the normal
   SIP authentication mechanisms, such as Digest as defined in Section
   22 of [RFC3261].  The mechanism used for conveying the metadata
   information MUST ensure integrity and SHOULD ensure confidentially of
   the information.  In order to achieve these, an end-to-end SIP
   encryption mechanism, such as S/MIME described in [RFC3261], SHOULD
   be used.

   If a strong end-to-end security means (such as above) is not
   available, it is RECOMMENDED that a SRC use mutual hop-by-hop
   Transport Layer Security (TLS) authentication and encryption
   mechanisms described in "SIPS URI Scheme" and "Interdomain Requests"



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   of [RFC3261].

   This document describes an extensive set of metadata that may be
   recorded by the SRS.  Most of the metadata could be considered
   private data.  Some implementations may have SRC choose parts of
   Metadata that can be sent to SRS.  In other cases, SRCs may send
   metadata that is not appropriate for the SRS to record.  What of this
   metadata is actually recorded by the SRS must be carefully considered
   (a "retention policy") to balance privacy concerns with usability.
   Implementations MUST control what metadata is recorded, and MUST NOT
   save metadata sent by the SRC that does not conform to the retention
   policy of the SRS.


10.  IANA Considerations

   This specification registers a new XML namespace, and a new XML
   schema.

10.1.  SIP recording metadata Schema Registration

   URI: urn:ietf:params:xml:ns:recording

   Registrant Contact: IETF SIPREC working group, Ram mohan
   R(rmohanr@cisco.com)

   XML: the XML schema to be registered is contained in Section 8.

   Its first line is <?xml version="1.0" encoding="UTF-8"?> and its last
   line is </xs:schema>


11.  Acknowledgement

   We wish to thank John Elwell, Henry Lum, Leon Portman, De Villers,
   Andrew Hutton(Siemens-Enterprise), Deepanshu Gautam(Huawei),Charles
   Eckel(Cisco), Muthu Arul Mozhi (Cisco), Michael Benenson(Cisco),
   Hadriel Kaplan (ACME), Brian Rosen, Scott Orton(Broadsoft), Ofir Roth
   (NICE), Mary Barnes(Polycom), Ken Rehor(Cisco) for their valuable
   comments and inputs.

   We wish to thank Joe Hildebrand(Cisco), Peter Saint-Andre(Cisco),
   Matt Miller(Cisco) for the valuable XML related guidance and Martin
   Thompson for validating the XML schema and providing comments on the
   same.


12.  References



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12.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2141]  Moats, R., "URN Syntax", RFC 2141, May 1997.

   [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.

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              January 2004.

   [RFC3339]  Klyne, G., Ed. and C. Newman, "Date and Time on the
              Internet: Timestamps", RFC 3339, July 2002.

   [RFC4566]  Handley, M., Jacobson, V., and C. Perkins, "SDP: Session
              Description Protocol", RFC 4566, July 2006.

   [RFC4574]  Levin, O. and G. Camarillo, "The Session Description
              Protocol (SDP) Label Attribute", RFC 4574, August 2006.

   [RFC4796]  Hautakorpi, J. and G. Camarillo, "The Session Description
              Protocol (SDP) Content Attribute", RFC 4796,
              February 2007.

   [RFC3840]  Rosenberg, J., Schulzrinne, H., and P. Kyzivat,
              "Indicating User Agent Capabilities in the Session
              Initiation Protocol (SIP)", RFC 3840, August 2004.

   [RFC4122]  Leach, P., Mealling, M., and R. Salz, "A Universally
              Unique IDentifier (UUID) URN Namespace", RFC 4122,
              July 2005.

   [RFC4648]  Josefsson, S., "The Base16, Base32, and Base64 Data
              Encodings", RFC 4648, October 2006.

12.2.  Informative References

   [RFC6341]  Rehor, K., Portman, L., Hutton, A., and R. Jain, "Use
              Cases and Requirements for SIP-Based Media Recording
              (SIPREC)", RFC 6341, August 2011.

   [I-D.ietf-siprec-architecture]
              Hutton, A., Portman, L., Jain, R., and K. Rehor, "An
              Architecture for Media Recording using the Session



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              Initiation Protocol", draft-ietf-siprec-architecture-11
              (work in progress), December 2013.

   [RFC2648]  Moats, R., "A URN Namespace for IETF Documents", RFC 2648,
              August 1999.

   [RFC3326]  Schulzrinne, H., Oran, D., and G. Camarillo, "The Reason
              Header Field for the Session Initiation Protocol (SIP)",
              RFC 3326, December 2002.

   [RFC3325]  Jennings, C., Peterson, J., and M. Watson, "Private
              Extensions to the Session Initiation Protocol (SIP) for
              Asserted Identity within Trusted Networks", RFC 3325,
              November 2002.


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 Solutions and Networks
   Bangalore, Karnataka
   India

   Email: partha@parthasarathi.co.in


   Paul Kyzivat
   Huawei
   Hudson, MA
   USA

   Email: pkyzivat@alum.mit.edu








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