SIPREC M. Yan
Internet-Draft P. Kyzivat
Intended status: Informational Huawei
Expires: August 18, 2014 February 14, 2014
Overview for MSRP Recording based on SIPREC
draft-yan-siprec-msrp-recording-00
Abstract
SIPREC is capable of recording interactive text media that is
transmitted via RTP. However that format is not commonly used for
message or chat scenarios. There is also a need for recording text
media carried via MSRP. One case of note is exchange of text between
hearing-impaired users and emergence service bureaus. Also,
recording support is needed for MSRP used in chat conferences and
multimedia conferences.
This document describes how to achieve MSRP channel recording within
the mechanism of SIP Recording (SIPREC).
Requirements Language
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 RFC 2119 [RFC2119].
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
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Internet-Drafts are draft documents valid for a maximum of six months
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on August 18, 2014.
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Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. MSRP Recording Architecture . . . . . . . . . . . . . . . . . 3
3.1. MSRP Client acts as SRC . . . . . . . . . . . . . . . . . 3
3.2. MSRP Relay acts as SRC . . . . . . . . . . . . . . . . . 4
3.3. MSRP Switch acts as SRC . . . . . . . . . . . . . . . . . 4
4. MSRP Recording Protocol . . . . . . . . . . . . . . . . . . . 5
5. Metadata . . . . . . . . . . . . . . . . . . . . . . . . . . 5
6. Open Issues . . . . . . . . . . . . . . . . . . . . . . . . . 5
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
8. Security Considerations . . . . . . . . . . . . . . . . . . . 6
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
9.1. Normative References . . . . . . . . . . . . . . . . . . 6
9.2. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
SIPREC is capable of recording interactive text media that is
transmitted via RTP, as defined by [RFC4103]. However that format is
not commonly used for message or chat scenarios. There is also a
need for recording text media carried via MSRP. One case of note is
exchange of text between hearing-impaired users and emergence service
bureaus. Also, recording support is needed for MSRP used in chat
conferences (as defined by [I-D.ietf-simple-chat]) and multimedia
conferences (as defined by [RFC4597]).
Instant message media is carried by a variety of protocols such as
IRC, MSRP and XMPP/JINGLE. The SIP based protocol MSRP (as defined
by [RFC4975][RFC4976]) supports the delivery of messages and files
from one SIPUA to another. When a SIPREC SRC is recording a CS that
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contains an MSRP channel, it may want to record the messages passing
over that channel. To gain access to the messages, the SRC may act
as an MSRP client, relay, or switch. The SRC needs to replicate and
deliver the messages over an MSRP channel within a Recording Session
(RS) to an SRS. The replicated content could be in Message/CPIM
format containing plain text, HTML, images, etc. In this document,
file delivering sessions have not yet been considered. Other instant
message protocols, like IRC or XMPP, are out of scope.
This document describes how MRSP sessions are established between an
SRC and SRS, and used for conveying the replicated MSRP Media, and
also specifies metadata that describes the recorded MSRP sessions. A
Recording Session employing MSRP is established using the normal
procedures for establishing INVITE initiated dialogs [RFC3261] and
uses SDP for describing the media to be used during the session
[RFC4566] as described by [I-D.ietf-siprec-architecture].
2. Definitions
(TBD...)
3. MSRP Recording Architecture
For consistency with [RFC6341] and [I-D.ietf-siprec-architecture],
MSRP recording needs to deliver duplicated MSRP message content from
the SRC to the SRS, with suitable descriptive metadata. The SRC may
be associated with SIP UA (endpoint) with an MSRP client, or with a
SIP B2BUA that accesses the media via an MRSP Relay. An SRC may also
be associated with a SIP conference focus and an MSRP switch.
3.1. MSRP Client acts as SRC
[RFC4975][RFC4976] describes how an MSRP client communicates to
another MSRP client via a SIP session. A MSRP client that has access
to the MSRP content to be recorded may act as SRC. The MSRP client
may send the replicated media to the SRS along with corresponding
metadata.
If the MSRP client/SRC is aware the MSRP session needs to be
recorded, it can initiate the establishment of a SIP RS by sending an
INVITE to SRS, or vice-versa. The MSRP client/SRC is responsible for
notifying the other MSRP client involved in the CS that the MSRP
session is being recorded. The MSRP client/SRC is responsible for
complying with request from recording aware UAs or through some
configured policies indicating that the CS should not be recorded.
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+-------------+
| MSRP CLIENT |
+-------------+
^
| (Communication Session)
|
| SIP
v
+-------------+ (Recording Session) +-------------+
| MSRP CLIENT |<---------------------->| Recorder |
| (SRC) | SIP/Metadata | (SRS) |
+-------------+ +-------------+
Figure 1: MSRP Client Acts as SRC
3.2. MSRP Relay acts as SRC
(TBD... RFC4976)
+-------------+
| MSRP CLIENT |
+-------------+
^
| (Communication Session)
| SIP
+-------------+ (Recording Session) +-------------+
| MSRP RELAY |<---------------------->| Recorder |
| (SRC) | SIP/Metadata | (SRS) |
+-------------+ +-------------+
|
|
v
+-------------+
| MSRP CLIENT |
+-------------+
Figure 2: MSRP Relay Acts as SRC
3.3. MSRP Switch acts as SRC
(TBD... ietf-simple-chat)
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+-------------+ +-------------+
| MSRP CLIENT | | MSRP CLIENT |
+-------------+ +-------------+
^ ^
\ SIP / (Communication Session)
\ / SIP
+-------------+ +-------------+
| MSRP switch | (Recording Session) | Recorder |
| (SRC) |<------------------->| (SRS) |
+-------------+ SIP/Metadata +-------------+
/ \
/ SIP \ SIP
v v
+-------------+ +-------------+
| MSRP CLIENT | | MSRP CLIENT |
+-------------+ +-------------+
Figure 3: MSRP Switch Acts as SRC
4. MSRP Recording Protocol
There are several possible ways of passing CS MSRP messages from the
SRC to the SRS. Here are three:
1. For each CS MSRP channel that is recorded, a corresponding new
MSRP channel is created in the RS.
2. For each CS MSRP channel that is recorded, a corresponding MSRP
channel is dedicated in the RS. When recording of the CS MSRP
channel ceases, the corresponding MSRP channel may be reassigned.
3. MSRP messages from multiple MSRP participants of a CS are
multiplexed (mixed) over a single MSRP channel in the RS.
5. Metadata
(TBD...)
6. Open Issues
o Is there any need for in-band indication that MSRP is being
recorded?
o MSRP-based file transfers (in scope or not?)
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7. IANA Considerations
This document contains no IANA considerations.
8. Security Considerations
Not explicitly covered in this version.
9. References
9.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 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.
[RFC4975] Campbell, B., Mahy, R., and C. Jennings, "The Message
Session Relay Protocol (MSRP)", RFC 4975, September 2007.
[RFC4976] Jennings, C., Mahy, R., and A. Roach, "Relay Extensions
for the Message Sessions Relay Protocol (MSRP)", RFC 4976,
September 2007.
[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.
[I-D.ietf-simple-chat]
Niemi, A., Garcia, M., and G. Sandbakken, "Multi-party
Chat Using the Message Session Relay Protocol (MSRP)",
draft-ietf-simple-chat-18 (work in progress), January
2013.
9.2. Informative References
[RFC4103] Hellstrom, G. and P. Jones, "RTP Payload for Text
Conversation", RFC 4103, June 2005.
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[RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session
Description Protocol", RFC 4566, July 2006.
[RFC4597] Even, R. and N. Ismail, "Conferencing Scenarios", RFC
4597, August 2006.
Authors' Addresses
Michael Yan
Huawei
Email: michael.yan@huawei.com
Paul H. Kyzivat
Huawei
Email: pkyzivat@alum.mit.edu
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