SIPREC R. Ravindranath
Internet-Draft Cisco Systems
Intended status: Standards Track Parthasarathi. Ravindran
Expires: September 19, 2016 Nokia Networks
Paul. Kyzivat
Huawei
March 18, 2016

Session Initiation Protocol (SIP) Recording Metadata
draft-ietf-siprec-metadata-21

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 September 19, 2016.

Copyright Notice

Copyright (c) 2016 IETF Trust and the persons identified as the document authors. All rights reserved.

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Table of Contents

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(SRS) and the Recording metadata format, the requirements for which are described in [RFC6341] and the architecture for which is described in [RFC7245].

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) [UML-REF] 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(or object diagrams). The linkages used in the metadata model of this document are associations.

This document also refers to the terminlogy defined in [RFC6341].

4. Metadata Model

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

				

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

The metadata model is a class diagram in UML. The model describes the structure of 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 represent the relationships which can be associations or composition. The metadata is conveyed from SRC to SRS.

The model allows metadata describing communications sessions to be communicated to the SRS as a series of snapshots, each representing the state as seen by a single SRC at a particular instant in time. Metadata changes from one snapshot to another 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). For example, the label attribute within the 'stream' XML element references an SDP 'a=label' attribute that identifies an m-line within the Recording Session(RS) SDP. The SRS would learn the media properties from media line.

5. Recording metadata format from SRC to SRS

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 sent from SRC to SRS contain a'recording' element. The 'recording' element acts as a container for all other elements in this XML document. A 'recording' object is an XML document. It has the XML declaration and 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

This document defines a new namespace URI for elements defined by this specification is the following URN:

urn:ietf:params:xml:ns:recording:1

5.1.2. recording

The 'recording' element MUST contain an xmlns namespace attribute with value as urn:ietf:params:xml:ns:recording:1. Exactly 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.

6.1. Recording Session

					
+-------------------------------+
| Recording Session (RS)        | 
+-------------------------------+
|                               |1..*     0..*
|     start-time                |-------------- Media Stream
|     end-time                  |
|                               |
|                               |
+-------------------------------+ 
      |1..*            | 1..* 
      |                |      
      |0..*            | 0..* 
 Communication    Communication 
 Session          Session Group(CS Group)
					
				

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

RS object is represented in XML schema using 'recording' element. That in turn relies on the SIP/SDP session with which the XML document is associated to provide the attributes of the RS element.

6.1.1. Attributes

An RS class has the following attributes:

'start-time' and 'end-time' attribute values are derivable from Date header(if present in SIP message) in RS. In cases where Date header is not present, 'start-time' is derivable from the time at which SRS receives the notification of SIP message to setup RS and and 'end-time' is derivable from the time at which SRS receives disconnect on the RS SIP dialog.

6.1.2. Linkages

Each instance of RS has:

CSs and CS-Groups are optional to accommodate persistent recording, where there may sometimes be none. A persistent RS is a SIP dialog that is setup between SRC to SRS even before any CS is setup. The metadata sent from SRC to SRS when the persistent RS SIP dialog is setup may not have any CS(and the related CS-Group) elements in the XML as there may be no session that is associated to the RS yet. For e.g; a phone acting as SRC can setup a RS with SRS possibly even before phone is part of a CS. Once the phone joins a CS, the same RS would be used to convey the CS metadata.

6.2. Communication Session Group

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

One instance of a Communication Session Group(CS-Group) class namely the CS-Group object provides association or grouping all related CS. For e.g, in a contact center flow a call can get transferred to multiple agents. Each of these can trigger setup of new CS. In cases where the SRC knows the related CSs it can group them using the CS-Group element. CS-Group object is represented in XML schema using 'group' element.

6.2.1. Attributes

A CS-Group has the following attributes:

6.2.2. Linkages

The linkages between CS-Group class and other classes are associations. A CS-Group is associated with RS and CS in the following manner:

6.3. Communication Session

					
 
Recording	       Communication 
Session            Session Group(CS Group)
   |1..*                  | 0..1
   |                      | 
   |0..*                  | 1..* 
+-------------------------------+
|   Communication Session (CS)  | 
+-------------------------------+ 
|   session_id                  | 
|   sipSessionID                |
|   reason                      |
|   group-ref                   |
|   start-time                  |
|   stop-time                   |
+-------------------------------+
   |                      |
   | 0..*                 |0..1              
   |                      |                  
   | 0..*                 |0..*              
Participant              Media Stream

					
				

A Communication Session(CS) class and its object in the metadata model represents the CS and its properties as seen by SRC. CS object is represented in XML schema using 'session' element.

6.3.1. Attributes

A CS class has the following attributes:

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 its local policy. The ability for the SRC to influence this policy is outside the scope of this document. However if there are implementations where SRC desires to specify its own policy preferences, this could be sent as extension data attached to the CS.

6.3.2. Linkages

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

Association between CS and Media Stream allows:

Association between CS and RS allows:

6.4. CSRSAssociation

					
					
                     1..*            0..*
   Recording                             Communication  
    Session        ----------+---------- Session
                             |
                             |
                             |
                   +-----------------------+
                   | CSRSAssociation       |
                   |                       |
                   +-----------------------+
                   | associate-time        |
                   | disassociate-time     |
                   | session_id            |
                   +-----------------------+
					
				

The CSRSAssociation 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.

The CSRSAssociation is represented in XML using 'sessionrecordingassoc' XML element.

6.4.1. Attributes

CSRSAssociation class has the following attributes:

6.4.2. Linkages

CSRSAssociation class is linked to CS and RS classes.

6.5. Participant

					
 Communication Session (CS)
           | 0..*
           | 
           | 0..* 
+-------------------------------+               
|          Participant          |
+-------------------------------+               
|  nameID                       |
|  participant_id               |
|                               |
+-------------------------------+
        | 0..*       1..*|                            
receives|                |sends                    
        | 0..*       0..*|                        
          Media Stream
		  

				

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.

Participant object is represented in XML schema using 'participant' element.

6.5.1. Attributes

A participant class has two attributes:

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 MediaStream (MS) and CS class using association relationship. The association between participant and MS allows:

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.

6.6. ParticipantCSAssociation

					
					
                     1..*            0..*
   Communication
    Session        ----------+---------- Participant
                             |
                             |
                             |
                   +-------------------------+
                   | ParticipantCSAssociation|
                   |                         |
                   |                         |
                   +-------------------------+
                   | associate-time          |
                   | disassociate-time       |
                   | param                   |
                   | participant_id          |
                   | session_id              |
                   +-------------------------+
					
				

The ParticipantCSAssociation 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.)

ParticipantCSAssociation object is represented in XML schema using 'participantsessionassoc' element.

6.6.1. Attributes

ParticipantCS association class has the following attributes:

6.6.2. Linkages

The participantCSAssociation class is linked to participant and CS classes.

6.7. Media Stream

					
                                Participant
                            | 0..*       1..*|
                    receives|                |sends
                            | 0..*       0..*|
                         +-------------------------+
                         |          Media Stream   |
Communication 0..1  0..* +-------------------------+
  Session    ------------|                         |
                         |  label                  |
                         |  content-type           |
                         |  stream_id              |
                         |  session_id             |
                         +-------------------------+
                                  0..*| 
                                      |
                                      |
                                  1..*| 
                                Recording Session  

					
				

A MS class (and its objects) has the properties of media as seen by SRC and sent to SRS. Different snapshots of a MS objects 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.).

MS object is represented in XML schema using 'stream' element.

6.7.1. Attributes

A MS class has the the following attributes:

The metadata model can include media streams that are not being delivered to the SRS. For example, an SRC offers audio, video towards SRS which in response accepts only audio. The metadata snapshots sent from SRC to SRS can continue to indicate the changes to video stream as well.

6.7.2. Linkages

A MS class 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.

6.8. ParticipantStreamAssociation

					

+-------------------------+
| ParticipantStream       |
| Association             |
+-------------------------+   +----------Participant
| association-time        |   |       0..*| 1..*|
| disassociaton-time      |---+       recv|     |sends
| send                    |   |       0..*| 0..*|
| recv                    |   |           |     |
| participant_id          |   |           |     | 
+-------------------------+   |           |     |
                              +----------Media Stream

				
				

A ParticipantStreamAssociation class describes the association of a Participant to a MS for a period of time, as a sender or as a receiver, or both.

This class is represented in XML using <participantstreamassoc> element.

6.8.1. Attributes

A ParticipantStreamAssociation class has the following attributes:

<participantstreamassoc> XML element is used to represent 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' element that does not have any 'send' and 'recv' elements, it means that participant is neither contributing to any streams nor receiving any streams.

6.8.2. Linkages

The ParticipantStreamAssociation class is linked to participant and MS classes.

6.9. Syntax of date/time XML elements

XML elements <associate-time>, <disassociate-time>, <start-time> and <stop-time> contain strings representing the date and time. The value of these elements MUST follow the IMPP datetime format [RFC3339]. Timestamps that contain 'T' or 'Z' MUST use the capitalized forms.

As a security measure, the timestamp element MUST 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:

The above mentioned unique-id mechanism SHOULD be used for each metadata element. Multiple SRC's can refer to the same element/UUID (how each SRC learns the UUID here is out of scope of this document). If two SRCs use the same UUID, it MUST retain the UUID/element mapping. If the SRS detects that a UUID is mapped to more than one element at any point of time it MUST treat this as a error. For example, the SRS may choose to reject or ignore the portions of metadata where it detects same UUID is mapped to a different elements other than the expected element (the SRS learns the mapped UUID when it sees a element for the first time in a metadata instance).

6.11. Metadata version Indicator

Metadata version is defined to help SRC and SRS to know the version of metadata XML schema used. SRCs and SRSs that support this specification MUST use version 1 in the namespace(urn:ietf:params:xml:ns:recording:1) in all the XML documents. 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 the metadata XML schema changes.

7. Recording metadata snapshot request format

SRS can explicitly request metadata snapshot from SRC. To request a metadata snapshot the SRS MUST send a SIP request message with a XML document having the namespace urn:ietf:params:xml:ns:recording:1. The XML document has the following elements.

The example below shows a metadata snapshot request from SRS.

		     	
<?xml version="1.0" encoding="UTF-8"?>
  <requestsnapshot xmlns='urn:ietf:params:xml:ns:recording:1'>
  <requestreason xml:lang="it">SRS internal error</requestreason>
</requestsnapshot>
		      
		     

Example metadata snapshot request from SRS to SRC

8. SIP Recording Metadata Example

8.1. 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==">
	<sipSessionID>ab30317f1a784dc48ff824d0d3715d86;
        remote=47755a9de7794ba387653f2099600ef2</sipSessionID>
	<group-ref>7+OTCyoxTmqmqyA/1weDAg==</group-ref>
	<!-- Standardized extension -->
    <mydata xmlns='http://example.com/my'>
	  <structure>FOO!</structure>
	   <whatever>bar</whatever>
	</mydata>
  </session>
  <participant participant_id="srfBElmCRp2QB23b7Mpk0w==">
	<nameID aor="sip:bob@biloxi.com">
	   <name xml:lang="it">Bob B</name>
	</nameID>
	<!-- Standardized extension -->
	<mydata xmlns='http://example.com/my'>
		<structure>FOO!</structure>
		<whatever>bar</whatever>
	</mydata>
  </participant>
  <participant participant_id="zSfPoSvdSDCmU3A3TRDxAw==">
	<nameID aor="sip:Paul@biloxy.com">
	  <name xml:lang="it">Paul</name>
	</nameID>
	<!-- Standardized extension -->
	<mydata xmlns='http://example.com/my'>
	   <structure>FOO!</structure>
	   <whatever>bar</whatever>
	</mydata>
  </participant>
  <stream stream_id="UAAMm5GRQKSCMVvLyl4rFw=="
          session_id="hVpd7YQgRW2nD22h7q60JQ==">
	<label>96</label>
  </stream>
  <stream stream_id="i1Pz3to5hGk8fuXl+PbwCw=="
           session_id="hVpd7YQgRW2nD22h7q60JQ==">
	 <label>97</label>
  </stream>
  <stream stream_id="8zc6e0lYTlWIINA6GR+3ag=="
           session_id="hVpd7YQgRW2nD22h7q60JQ==">
	<label>98</label>
  </stream>
  <stream stream_id="EiXGlc+4TruqqoDaNE76ag=="
           session_id="hVpd7YQgRW2nD22h7q60JQ==">
	<label>99</label>
  </stream>
  <sessionrecordingassoc session_id="hVpd7YQgRW2nD22h7q60JQ==">
		<associate-time>2010-12-16T23:41:07Z</associate-time>
  </sessionrecordingassoc>
  <participantsessionassoc
       participant_id="srfBElmCRp2QB23b7Mpk0w=="
       session_id="hVpd7YQgRW2nD22h7q60JQ==">
	<associate-time>2010-12-16T23:41:07Z</associate-time>
  </participantsessionassoc>
  <participantsessionassoc
       participant_id="zSfPoSvdSDCmU3A3TRDxAw=="
       session_id="hVpd7YQgRW2nD22h7q60JQ==">
	   <associate-time>2010-12-16T23:41:07Z</associate-time>
  </participantsessionassoc>
  <participantstreamassoc
       participant_id="srfBElmCRp2QB23b7Mpk0w==">
	   <send>i1Pz3to5hGk8fuXl+PbwCw==</send>
	   <send>UAAMm5GRQKSCMVvLyl4rFw==</send>
	   <recv>8zc6e0lYTlWIINA6GR+3ag==</recv>
	   <recv>EiXGlc+4TruqqoDaNE76ag==</recv>
  </participantstreamassoc>
  <participantstreamassoc
      participant_id="zSfPoSvdSDCmU3A3TRDxAw==">
	  <send>8zc6e0lYTlWIINA6GR+3ag==</send>
	  <send>EiXGlc+4TruqqoDaNE76ag==</send>
	  <recv>UAAMm5GRQKSCMVvLyl4rFw==</recv>
	  <recv>i1Pz3to5hGk8fuXl+PbwCw==</recv>
  </participantstreamassoc>
</recording>
                           
					

Example metadata snapshot from SRC to SRS

8.2. 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==">
      <nameID aor="sip:bob@biloxi.com">
		<name xml:lang="it">Bob R</name>
	  </nameID>     
    </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

9. 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:1"
      elementFormDefault="qualified"
      attributeFormDefault="unqualified">
    <!-- This import brings in the XML language attribute xml:lang-->
    <xs:import namespace="http://www.w3.org/XML/1998/namespace"
                 schemaLocation="https://www.w3.org/2001/xml.xsd"/>
    <xs:element name="recording" type="tns:recording"/>
    <xs:complexType name="recording">
        <xs:sequence>
            <xs:element name="datamode" type="tns:dataMode"
                  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="sipSessionID" type="xs:string" minOccurs="0"
                   maxOccurs="unbounded"/>
           <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"
                  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: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: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: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>
        <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:element name="requestsnapshot" type="tns:requestsnapshot"/>
    <xs:complexType name="requestsnapshot">
       <xs:sequence>
          <xs:element name="requestreason" type="tns:name"  minOccurs="0"/>
          <xs:any namespace='##other'
            minOccurs='0'
            maxOccurs='unbounded'
            processContents='lax'/>
       </xs:sequence>
     </xs:complexType>
</xs:schema>
            
	   

10. Security Considerations

This document describes an extensive set of metadata that may be recorded by the SRS. Most of the metadata could be considered private data. The procedures mentioned in security consideration section of [I-D.ietf-siprec-protocol] MUST be implemented by SRC and SRS for mutual authentication and to protect the content of the metadata in the RS.

An SRC MAY, by policy, choose to limit the parts of the metadata sent to the SRS for recording. And the policy of the SRS might not require all the metadata it receives. For the sake of data minimization, the SRS MUST NOT record additional metadata that is not explicitly required by local policy. Metadata in storage needs to be provided with a level of security that is comparable to that of the recording session.

11. IANA Considerations

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

11.1. SIP recording metadata Schema Registration

URI: urn:ietf:params:xml:ns:recording:1

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>

12. Acknowledgement

Thanks to John Elwell, Henry Lum, Leon Portman, De Villers, Andrew Hutton, Deepanshu Gautam,Charles Eckel, Muthu Arul Mozhi, Michael Benenson, Hadriel Kaplan, Brian Rosen, Scott Orton, Ofir Roth, Mary Barnes, Ken Rehor, Gonzalo Salgueiro, Yaron Pdut, Alissa Cooper, Stephen Farrell and Ben Campbell for their valuable comments and inputs.

Thanks to Joe Hildebrand, Peter Saint-Andre, Matt Miller for helping in writing the XML schema and Martin Thomson for validating the XML schema and providing comments on the same.

13. References

13.1. Normative References

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997.
[RFC2141] Moats, R., "URN Syntax", RFC 2141, DOI 10.17487/RFC2141, 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, DOI 10.17487/RFC3261, June 2002.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, January 2004.
[RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet: Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002.
[RFC4566] Handley, M., Jacobson, V. and C. Perkins, "SDP: Session Description Protocol", RFC 4566, DOI 10.17487/RFC4566, July 2006.
[RFC4574] Levin, O. and G. Camarillo, "The Session Description Protocol (SDP) Label Attribute", RFC 4574, DOI 10.17487/RFC4574, August 2006.
[RFC4796] Hautakorpi, J. and G. Camarillo, "The Session Description Protocol (SDP) Content Attribute", RFC 4796, DOI 10.17487/RFC4796, February 2007.
[RFC3840] Rosenberg, J., Schulzrinne, H. and P. Kyzivat, "Indicating User Agent Capabilities in the Session Initiation Protocol (SIP)", RFC 3840, DOI 10.17487/RFC3840, August 2004.
[RFC4122] Leach, P., Mealling, M. and R. Salz, "A Universally Unique IDentifier (UUID) URN Namespace", RFC 4122, DOI 10.17487/RFC4122, July 2005.
[RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006.
[I-D.ietf-siprec-protocol] Portman, L., Lum, H., Eckel, C., Johnston, A. and A. Hutton, "Session Recording Protocol", Internet-Draft draft-ietf-siprec-protocol-18, September 2015.

13.2. Informative References

[RFC6341] Rehor, K., Portman, L., Hutton, A. and R. Jain, "Use Cases and Requirements for SIP-Based Media Recording (SIPREC)", RFC 6341, DOI 10.17487/RFC6341, August 2011.
[I-D.ietf-insipid-session-id] Jones, P., Salgueiro, G., Pearce, C. and P. Giralt, "End-to-End Session Identification in IP-Based Multimedia Communication Networks", Internet-Draft draft-ietf-insipid-session-id-18, February 2016.
[RFC7245] Hutton, A., Portman, L., Jain, R. and K. Rehor, "An Architecture for Media Recording Using the Session Initiation Protocol", RFC 7245, DOI 10.17487/RFC7245, May 2014.
[RFC2648] Moats, R., "A URN Namespace for IETF Documents", RFC 2648, DOI 10.17487/RFC2648, August 1999.
[RFC3326] Schulzrinne, H., Oran, D. and G. Camarillo, "The Reason Header Field for the Session Initiation Protocol (SIP)", RFC 3326, DOI 10.17487/RFC3326, 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, DOI 10.17487/RFC3325, November 2002.
[RFC4235] Rosenberg, J., Schulzrinne, H. and R. Mahy, "An INVITE-Initiated Dialog Event Package for the Session Initiation Protocol (SIP)", RFC 4235, DOI 10.17487/RFC4235, November 2005.
[UML-REF] OMG, "Unified Modeling Language (UML)", 2011.

Authors' Addresses

Ram Mohan Ravindranath Cisco Systems Cessna Business Park Bangalore, Karnataka 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