siprec Ram Mohan. Ravindranath
Internet-Draft Parthasarathi. Ravindran
Intended status: Standards Track Paul. Kyzivat
Expires: September 9, 2011 Cisco Systems, Inc.
March 8, 2011
Session Initiation Protocol (SIP) Recording Metadata Format
draft-ram-siprec-metadata-format-01
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. The requirements for which are described in
[I-D.ietf-siprec-req], the architecture for which is described in
[I-D.ietf-siprec-architecture], and the metadata model viewed by
Session Recording Server is described in [I-D.ram-siprec-metadata].
This document focuses on the Recording metadata format which
describes the communication session.
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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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 9, 2011.
Copyright Notice
Copyright (c) 2011 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
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(http://trustee.ietf.org/license-info) in effect on the date of
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Recording Metadata Format . . . . . . . . . . . . . . . . . . 3
4. SIP Recording Metadata document format . . . . . . . . . . . . 4
4.1. Contents . . . . . . . . . . . . . . . . . . . . . . . . . 4
4.2. XML data format . . . . . . . . . . . . . . . . . . . . . 4
4.2.1. Namespace . . . . . . . . . . . . . . . . . . . . . . 5
4.2.2. recording-metadata . . . . . . . . . . . . . . . . . . 5
4.2.3. recording . . . . . . . . . . . . . . . . . . . . . . 5
4.2.4. group . . . . . . . . . . . . . . . . . . . . . . . . 5
4.2.5. session . . . . . . . . . . . . . . . . . . . . . . . 6
4.2.6. participant . . . . . . . . . . . . . . . . . . . . . 6
4.2.7. stream . . . . . . . . . . . . . . . . . . . . . . . . 6
4.2.8. extensiondata . . . . . . . . . . . . . . . . . . . . 7
4.2.9. start-time/stop-time . . . . . . . . . . . . . . . . . 7
5. SIP Recording Metadata Example . . . . . . . . . . . . . . . . 7
5.1. Complete SIP Recording Metatdata Example . . . . . . . . . 7
5.2. Partial Update of Recording metadata XML body . . . . . . 9
6. XML Schema definition for Recording metadata . . . . . . . . . 9
7. XML element usage in SIP methods . . . . . . . . . . . . . . . 13
8. Example with SIP and metadata XML+SDP . . . . . . . . . . . . 14
8.1. SRC Initiated Recording . . . . . . . . . . . . . . . . . 14
9. Security Considerations . . . . . . . . . . . . . . . . . . . 16
9.1. Connection Security . . . . . . . . . . . . . . . . . . . 16
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
10.1. SIP recording metadata Schema Registration . . . . . . . . 17
11. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 17
12. References . . . . . . . . . . . . . . . . . . . . . . . . . . 17
12.1. Normative References . . . . . . . . . . . . . . . . . . . 17
12.2. Informative References . . . . . . . . . . . . . . . . . . 18
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19
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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. The requirements for which are described in
[I-D.ietf-siprec-req], the architecture for which is described in
[I-D.ietf-siprec-architecture], and the metadata model viewed by
Session Recording Server is described in [I-D.ram-siprec-metadata].
This document focuses on the Recording metadata format which
describes the communication session. The delivery mechanism for
passing metadata is outside the scope of this document.
The Session Recording Client (SRC) SHALL initiate the Recording
Session. It should be noted that the Recording Session is a
completely independent from the Communication Session that is being
recorded at both the SIP dialog level and at the session level.
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. Recording Metadata Format
Recording Metadata is the data that describes the communication
session. Metadata has to be conveyed from SRC to SRS, further the
metadata MAY be conveyed in the Recording Session dialog and SRS may
send metadata to convey Key information to SRC.
The media related details of metadata SHALL be passed across using
session description protocol (SDP) [RFC4566]. SDP attributes
describes about different media formats like audio, video. The other
metadata attributes like participant details MUST be passed across in
new Recording specific XML document namely application/recording.
The linkage between application/recording XML schema and metadata SDP
is done using the SDP label attribute (a=label:xxx) referenced in
[RFC4574].
Metadata is passed across in Recording Session(RS) incrementally
whenever there is a change in CS.
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4. SIP Recording Metadata document format
4.1. Contents
Recording Metadata document is an XML document which will be embedded
as a message body. The document contains
o recording-metadata element MUST present in all recording metadata
XML document. recording-metadata acts as container for all other
elements in this XML document.
o Elements like recording, session, participant, stream are under
recording-metadata element directly with appropriate parent id and
have separate URN UUID for passing the partial information of
metadata. In case of partial metadata, recording-metadata element
and the relevant updated elements will be passed by SRC and the
elements are identified in SRS using URN UUID and parent id.
o Open item: Whether partial data has to be passed in the level
metadata block like stream, participant or individual elements in
metadata block. The current approach is based on metadata block
which helps is reducing the number URN UUID maintained in SRC and
SRS. This decision of which approach needs discussion before
closure
o recording element MUST be present in the first metadata XML
document of a given session. recording element has unique id based
on URN UUID [RFC4122].
o Group element provides the information about the communication
session group
o Session element provides the information about the communication
session
o Participant element provides information regarding the specific
participant involved in the recording
o Stream element indicates SDP media lines associated with the CS
and participants
o ExtensionData element provides the mechanism by which namespace/
element shall be extended with standard or proprietary
information.
4.2. XML data format
Recording-metadata object is a XML document. It MUST have the XML
declaration and it SHOULD contain an encoding declaration in the XML
declaration, e.g., "". 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 conforms to this specification MUST accept the
UTF-8 character encoding to ensure the minimal interoperability.
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Syntax and semantics error in recording XML document has to be
informed to the originator using application specific mechanism.
4.2.1. 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 as follows: urn:ietf:params:xml:ns:recording
4.2.2. recording-metadata
recording-metadata element MUST contain an xmlns namespace attribute
with value as urn:ietf:params:xml:ns:siprec. Atleast one recording-
metadata element MUST present in the all recording metadata XML
document.
recording-metadata element has recording, group, session, stream
elements.
dataMode element shows whether the XML document is complete document
or partial update. The default value is complete.
4.2.3. recording
recording element has unique id based on URN UUID [RFC4122] attribute
and this attribute helps to uniquely identify recording element.
There are other elements associated in the recording element. The
element information is as follows:
o recording requestor attribute indicates whether SRC or SRS
initiates the particular session. The default value is SRC.
o recording type shows whether the type of recording belongs to
selective or persistent. The default value is selective.
4.2.4. group
Each communication session group (CSG) has one group tuple.
Each group element has unique URN UUID attribute which helps to
uniquely identify CSG.
Each group MAY have initiator entity attribute which contains SIP/
SIPS URI to identify the device which acts as Session Recording
Client (SRC). The entity attribute SIP/SIPS URI FQDN or IP address
represents the device and may not have user part.
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4.2.5. session
Each communication session(CS) has one session tuple.
Each session element has unique URN UUID attribute which helps to
uniquely identify CS and group URN UUID to associate session with
specific group element.
Reason element MAY be included to indicate the reason for
termination.
4.2.6. participant
Each communication session user is defined by one participant tuple.
The streams tuple in each participant is associating SDP m-lines with
the participant.
send/recv tuple in each participant is associating SDP m-lines with
the participant. send element indicates that participant is sending
the stream of media with the mentioned media description. recv
element indicates that participant is receiving the stream and by
default all pariticipant will receive the stream. recv element has
relevance in case whisper call scenario wherein few of the
participant in the session receives the stream and not others.
Participant MUST have AOR element which contains SIP/SIPS URI to
identify the participant. AOR element is SIP/SIPS URI FQDN or IP
address which represents the user.
Each participant element has unique URN UUID attribute which helps to
uniquely identify participant and session URN UUID to associate
participant with specific session element. URN UUID of participant
*MUST* used in the scope of CSG and no new URN UUID has to be created
for the same element (participant, stream) between different CS in
the same CSG. In case URN UUID has to be used permanent, careful
usage of URN UUID to original AoR has to be decided by the
implementers and it is implementer's choice.
4.2.7. stream
This element indicates the SDP m-line properties like label
attributes, media mode. Label attribute is used to link m-line SDP
body using label attribute in SDP m-line. The media mode helps in
understanding whether the media is mixed or not.
Each stream element has unique URN UUID attribute which helps to
uniquely identify stream and session URN UUID to associate stream
with specific session element.
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4.2.8. extensiondata
extensiondata element SHALL include any other XML namespace.
Multiple namespace MAY exists under extensiondata. extensiondata
element exist in each level like recording, session, participant,
stream to provide extensiondata specific to each element.
extensiondata element has unique id based on URN UUID [RFC4122]
attribute and its parent id.
4.2.9. start-time/stop-time
start-time/stop-time contains a string indicating the date and time
of the status change of this tuple. The value of this element 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 start-time or stop-time MAY exist in the element namely
group, session, participant, stream 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.
5. SIP Recording Metadata Example
5.1. Complete SIP Recording Metatdata Example
The following example provides all the tuples involved in Recording
Metadata XML body.
SRCselectivesip:alice@cisco.comFOO!bar
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sip:romeo@example.comFOO!barFOO!barsip:romeo@example.comRomeo Montagueurn:uuid:8b53f3de-da39-4846-93c7-ee5e5f8f6f0burn:uuid:50000c9b-9191-40a4-8231-5bcbca5e2b17FOO!barsip:juliet@example.netJuliet Capuleturn:uuid:50000c9b-9191-40a4-8231-5bcbca5e2b17urn:uuid:8b53f3de-da39-4846-93c7-ee5e5f8f6f0b
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FOO!bar2010-12-16T23:41:07Z2010-12-16T23:41:07Z
SIP Recording Metadata Example XML body
5.2. Partial Update of Recording metadata XML body
The following example provides partial update in Recording Metadata
XML body for the above example. The example illustrate the stop time
of the specific stream.
partial2010-12-16T23:41:07Z
2010-12-16T23:41:07Z
Partial update of SIP Recording Example XML body
6. XML Schema definition for Recording metadata
This section defines XML schema for Recording metadata document
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7. XML element usage in SIP methods
Table 1 just provides the guidelines of XML element usage in SIP
methods and the table does not mandate SIP as a transport for this
XML body. Most of the columns are defined in [RFC3261], the column
'PRA' is for the PRACK method [RFC3262],'UPD' is for the UPDATE
method [RFC3311], 'SUB' is for the SUBSCRIBE method [RFC3265], 'NOT'
is for the NOTIFY method [RFC3265] and 'INF' is for the INFO method
[RFC3261] .
+----------------+-----+---+---+---+---+---+---+---+---+---+---+---+
|XML Element |where|ACK|BYE|CAN|INV|OPT|REG|PRA|UPD|SUB|NOT|INF|
+----------------+-----+---+---+---+---+---+---+---+---+---+---+---+
|recording | R | o | o | - | o | - | - | o | o | - | o | o |
| | | | | | | | | | | | | |
|recording | 2xx | - | o | - | o | - | - | - | o | - | - | - |
| | | | | | | | | | | | | |
|group | R | o | o | - | o | - | - | o | o | - | o | o |
| | | | | | | | | | | | | |
|group | 2xx | - | o | - | o | - | - | - | o | - | - | - |
| | | | | | | | | | | | | |
|session | R | o | o | - | o | - | - | o | o | - | o | o |
| | | | | | | | | | | | | |
|session | 2xx | - | o | - | o | - | - | - | o | - | - | - |
| | | | | | | | | | | | | |
|participant | R | o | - | - | o | - | - | o | o | - | o | o |
| | | | | | | | | | | | | |
|participant | 2xx | - | - | - | o | - | - | - | o | - | - | - |
| | | | | | | | | | | | | |
|stream | R | o | - | - | o | - | - | o | o | - | - | - |
| | | | | | | | | | | | | |
|stream | 2xx | - | - | - | o | - | - | - | o | - | - | - |
| | | | | | | | | | | | | |
+------------- --+-----+---+---+---+---+---+---+---+---+---+---+---+
Table 1: XML element usage in SIP Methods
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Open item: Whether it is allowed to have SIP specific table in this
draft? Pls provide your comments.
8. Example with SIP and metadata XML+SDP
This section describes the different use cases/messages for
delivering Metadata in a Recording Sessions.
8.1. SRC Initiated Recording
An SRC initiates Recording Session(RS) for recording a communication
session with audio and video media. SRC initiates the dialog by
sending an INVITE request to the SRS. INVITE is formed as specified
in [RFC3261] , SRC inserts recording metadata as an XML document and
SDP in multipart MIME message body [RFC2046]. The content type of
SIP header is set to application/rs-metadata+xml
[I-D.portman-siprec-protocol]. SRC MUST form SDP offer using the
normal procedures defined in [RFC3261]and [RFC3264]. SRC SHALL
include one m-line for each stream of each participant. If the
recording has to be started immediately then SRC MUST include an SDP
attribute of "a=sendonly" for each media line or "a=inactive" if it
is not ready to transmit the media. SRC MAY also include only one
m-line for all streams of same type for all participants depending on
whether it has the capability to mix the streams. SRC indicates the
mode (mixed or single) for each stream using a mode attribute. An
example wherein INVITE sent by an SRC is shown below:
INVITE sip:1041@recordingserver.cisco.com:5060;transport=tcp SIP/2.0
Max-Forwards: 70
To:
From: RecrdingClient ;tag=ds43d76263
Call-ID: 12548086970261@192.168.1.67
CSeq: 100 INVITE
Content-Length: xxx
Contact: ;audio;
Date: Tue, 23 Mar 2010 23:29:00 GMT
Content-Type: multipart/mixed;boundary=unique-boundary-1
MIME-Version: 1.0
--unique-boundary-1
Content-Type: application/SDP
...
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=label:96
a=sendonly
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...
m=video 49174 RTP/AVPF 96
a=rtpmap:96 H.264/90000
a=label:97
a=sendonly
...
m=audio 51372 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=label:98
a=sendonly
...
m=video 49176 RTP/AVPF 96
a=rtpmap:96 H.264/90000
a=label:99
a=sendonly
....
--unique-boundary-1
Content-type:application/rs-metadata+xml
SRCselectivesip:partha@rc1.cisco.comurn:uuid:8b53f3de-da39-4846-93c7-ee5e5f8f6f0burn:uuid:50000c9b-9191-40a4-8231-5bcbca5e2b17sip:paul@rc1.cisco.com
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urn:uuid:50000c9b-9191-40a4-8231-5bcbca5e2b17urn:uuid:8b53f3de-da39-4846-93c7-ee5e5f8f6f0b2010-12-16T23:41:07Z2010-12-16T23:41:07Z2010-12-16T23:41:07Z2010-12-16T23:41:07Z
--unique-boundary-1--
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 following sections will discuss each
of these aspects in more detail.
9.1. Connection Security
It is RECOMMENDED that a SRC authenticate 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
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MUST ensure integrity and SHOULD ensure confidentially of the
information. In order to achieve these, an end-to-end SIP encryption
mechanism, such as S/MIME described in [RFC3261], SHOULD be used.
If a strong end-to-end security means (such as above) is not
available, it is RECOMMENDED that a SRC use mutual hop-by-hop
Transport Layer Security (TLS) authentication and encryption
mechanisms described in "SIPS URI Scheme" and "Interdomain Requests"
of [RFC3261].
TBD: Other detailed security aspects
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 6.
Its first line is and its last
line is
11. Acknowledgement
We wish to thank Joe Hildebrand(Cisco), Peter Saint-Andre(Cisco) for
the valuable XML related guidance. Thanks to Michael
Benenson(Cisco), Leon Portman(Nice), Henry Lum(Alcatel-lucent), John
Elwell(Siemens) for their inputs and comments.
12. References
12.1. Normative References
[RFC2046] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part Two: Media Types", RFC 2046,
November 1996.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
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Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2141] Moats, R., "URN Syntax", RFC 2141, May 1997.
[RFC2648] Moats, R., "A URN Namespace for IETF Documents", RFC 2648,
August 1999.
[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.
[RFC3262] Rosenberg, J. and H. Schulzrinne, "Reliability of
Provisional Responses in Session Initiation Protocol
(SIP)", RFC 3262, June 2002.
[RFC3264] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model
with Session Description Protocol (SDP)", RFC 3264,
June 2002.
[RFC3265] Roach, A., "Session Initiation Protocol (SIP)-Specific
Event Notification", RFC 3265, June 2002.
[RFC3311] Rosenberg, J., "The Session Initiation Protocol (SIP)
UPDATE Method", RFC 3311, October 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.
[RFC4122] Leach, P., Mealling, M., and R. Salz, "A Universally
Unique IDentifier (UUID) URN Namespace", RFC 4122,
July 2005.
[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.
12.2. Informative References
[I-D.ietf-siprec-req]
Rehor, K., Portman, L., Hutton, A., and R. Jain,
"Requirements for SIP-based Media Recording (SIPREC)",
draft-ietf-siprec-req-07 (work in progress), March 2011.
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[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-01
(work in progress), October 2010.
[I-D.ram-siprec-metadata]
R, R., R, P., and P. Kyzivat, "Session Initiation Protocol
(SIP) Recording Metadata", draft-ram-siprec-metadata-04
(work in progress), March 2011.
[I-D.portman-siprec-protocol]
Portman, L., Lum, H., Johnston, A., and A. Hutton, "The
SIP-based Media Recording Protocol (SIPREC)",
draft-portman-siprec-protocol-03 (work in progress),
March 2011.
Authors' Addresses
Ram Mohan Ravindranath
Cisco Systems, Inc.
Cessna Business Park,
Kadabeesanahalli Village, Varthur Hobli,
Sarjapur-Marathahalli Outer Ring Road
Bangalore, Karnataka 560103
India
Email: rmohanr@cisco.com
Parthasarathi Ravindran
Cisco Systems, Inc.
Cessna Business Park,
Kadabeesanahalli Village, Varthur Hobli,
Sarjapur-Marathahalli Outer Ring Road
Bangalore, Karnataka 560103
India
Email: partr@cisco.com
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P. Kyzivat
Cisco Systems, Inc.
1414 Massachusetts Avenue
Boxborough, MA 01719
USA
Email: pkyzivat@cisco.com
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