| SIPREC | R. Ravindranath |
| Internet-Draft | Cisco Systems |
| Intended status: Standards Track | Parthasarathi. Ravindran |
| Expires: August 2, 2016 | Nokia Networks |
| Paul. Kyzivat | |
| Huawei | |
| January 30, 2016 |
Session Initiation Protocol (SIP) Recording Metadata
draft-ietf-siprec-metadata-19
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.
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This Internet-Draft will expire on August 2, 2016.
Copyright (c) 2016 IETF Trust and the persons identified as the document authors. All rights reserved.
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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].
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."
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(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].
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.
+-------------------------------+
| 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 |
| | | |
+------------------+ +----------------------+
The metadata model is a class diagram in Unified Modelling Language(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 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).
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.
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.
A recording object is an 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.
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:1
The <recording> element MUST contain an xmlns namespace attribute with value as urn:ietf:params:xml:ns:recording:1. 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".
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.
+-------------------------------+
| Recording Session (RS) |
+-------------------------------+
| |
| start-time |
| end-time |
| |
| |
+-------------------------------+
|1..* | 1..*
| |
|0..* | 0..*
Communication Communication
Session Session Group(CS Group)
Each instance of a Recording Session(RS) class namely the Recording Session Object represents a SIP session created between an SRC and SRS for the purpose of recording a Communication Session.
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.
A 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.
Each instance of RS has:
CSs and CSGs are optional to accommodate persistent recording, where there may sometimes be none.
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 Communication Session Group object provides association or linking of Communication Sessions.
CS-Group object is represented in XML schema using <group> element.
A CS-Group has the following attributes:
The linkages between CS-Group class and other classes are associations. A CS-Group is associated with RS and CS in the following manner:
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 a Communication Session and its properties needed as seen by SRC.
CS object is represented in XML schema using <session> element.
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.
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:
1..* 0..*
Recording Communication
Session ----------+---------- Session
|
|
|
+-----------------------+
| CSRSAssociation |
| |
+-----------------------+
| association-time |
| disassociaton-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.
CSRSAssociation class has the following attributes:
CSRSAssociation class is linked to CS and RS classes.
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.
Participant has a single defined attribute:
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.
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.
1..* 0..*
Communication
Session ----------+---------- Participant
|
|
|
+-------------------------+
| ParticipantCSAssociation|
| |
| |
+-------------------------+
| associateTime |
| disassociateTime |
| 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.
ParticipantCS association class has the following attributes:
The participantCSAssociation class is linked to participant and CS classes.
Participant
| 0..* 1..*|
receives| |sends
| 0..* 0..*|
+-------------------------+
| Media Stream |
Communication 0..1 0..* +-------------------------+
Session ------------| |
| label |
| content-type |
| stream_id |
| session_id |
+-------------------------+
A MS 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.).
MS object is represented in XML schema using <stream> element.
A MS class has the the following attributes:
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
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.
+-------------------------+
| ParticipantStream |
| Association |
+-------------------------+ +----------Participant
| association-time | | 0..*| 1..*|
| disassociaton-time |---+ recv| |sends
| send | | 0..*| 0..*|
| recv | | | |
| participant_id | | | |
+-------------------------+ | | |
+----------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.
This class is represented in XML using <participantstreamassoc> element.
A ParticipantStream association class has the following attributes:
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.
The participantStream association class is linked to participant and Stream classes.
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.
A Unique id is generated in two steps:
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)
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 the metadata XML schema changes.
This section gives an details of metadata snapshot request format. When SRS wishes to request metadata snapshot from SRC it MUST follow the syntax described in this section. The SRS requests metadata snapshot in a request message and SHOULD insert a XML document having the namespace urn:ietf:params:xml:ns:recording:1. The Request can have the following elements.
A <requestsnapshot> XML element MUST be present as the top level element in the XML document. A <requestreason> XML element that indicates the reason for requesting snapshot as a string MAY be present as a child XML element of <requestsnapshot>.
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>
SIP Recording Metadata Example 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
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"/>
<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>
This document describes an extensive set of metadata that may be recorded by the SRS. Most of the metadata could be considered private data. 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.
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 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" of [RFC3261].
Some implementations may have the SRC choose parts of metadata that can be sent to the SRS. In other cases, SRCs may send metadata that is not appropriate for the SRS to record. Which metadata is actually recorded by the SRS must be carefully considered 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 recording policy of the SRS. Metadata in storage needs to be provided with a level of security that is comparable to that of the recording session.
This specification registers a new XML namespace, and a new XML schema.
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>
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 and Alissa Cooper for their valuable comments and inputs.
Thanks to Joe Hildebrand, Peter Saint-Andre, Matt Miller for helping in writing the XML schema and Martin Thompson for validating the XML schema and providing comments on the same.