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-14
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
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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 . . . . . . . . . . . . . . . . . . 29
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"/>
<!-- This import brings in the RFC 4235 dialog-info participant params -->
<xs:import namespace='urn:ietf:params:xml:ns:dialog-info'
schemaLocation='http://iana.org/assignments/xml-registry/schema/dialog-info.xsd'/>
<xs:element name="recording" type="tns:recording"/>
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<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="reason" type="tns:reason" minOccurs="0"
maxOccurs="unbounded"/>
<xs:element name="group-ref" type="xs:base64Binary"
minOccurs="0" maxOccurs="1"/>
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<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: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"/>
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<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: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>
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</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: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
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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].
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.
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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
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.
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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
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
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Paul Kyzivat
Huawei
Hudson, MA
USA
Email: pkyzivat@alum.mit.edu
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