One document matched: draft-portman-siprec-protocol-03.txt
Differences from draft-portman-siprec-protocol-02.txt
SIPREC L. Portman, Ed.
Internet-Draft NICE Systems
Intended status: Informational H. Lum
Expires: September 2, 2011 Genesys, Alcatel-Lucent
A. Johnston
Avaya
A. Hutton
Siemens Enterprise Communications
March 1, 2011
The SIP-based Media Recording Protocol (SIPREC)
draft-portman-siprec-protocol-03
Abstract
SIPREC Session Recording Protocol is used for establishing recording
session and reporting of the metadata of the communication session.
This document specifies the SIPREC Protocol (SIPREC). SIPREC is used
between Session Recording Client (SRC) and Session Recording Server
(SRS).
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 2, 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
(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
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. Overview of operations . . . . . . . . . . . . . . . . . . . . 5
4.1. Delivering recorded media . . . . . . . . . . . . . . . . 5
4.2. Conference focus as an SRC . . . . . . . . . . . . . . . . 6
4.3. Delivering recording metadata . . . . . . . . . . . . . . 7
5. SIP Extensions for Recording Session . . . . . . . . . . . . . 9
5.1. Callee Capabilities Extensions for SIP Recording . . . . . 9
5.1.1. src Feature Tag . . . . . . . . . . . . . . . . . . . 10
5.1.2. srs Feature Tag . . . . . . . . . . . . . . . . . . . 10
5.2. SDP handling . . . . . . . . . . . . . . . . . . . . . . . 10
5.3. Metadata . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.3.1. Requesting for metadata snapshot . . . . . . . . . . . 14
5.3.2. Recording Pause and Resume . . . . . . . . . . . . . . 14
6. SIP Extensions for Recording-aware User Agents . . . . . . . . 15
6.1. Recording awareness . . . . . . . . . . . . . . . . . . . 15
6.2. Providing recording indication . . . . . . . . . . . . . . 15
6.3. Recording preference . . . . . . . . . . . . . . . . . . . 16
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
7.1. New Content-Disposition Parameter Registrations . . . . . 16
7.2. Media Type Registration . . . . . . . . . . . . . . . . . 16
7.2.1. Registration of MIME Type application/rs-metadata . . 16
7.2.2. Registration of MIME Type
application/rs-metadata-request . . . . . . . . . . . 17
7.3. Info Package . . . . . . . . . . . . . . . . . . . . . . . 17
7.4. SDP Attributes . . . . . . . . . . . . . . . . . . . . . . 17
7.4.1. 'recording-aware' SDP Attribute . . . . . . . . . . . 17
7.4.2. 'record' SDP Attribute . . . . . . . . . . . . . . . . 18
7.4.3. 'recordpref' SDP Attribute . . . . . . . . . . . . . . 18
8. Security Considerations . . . . . . . . . . . . . . . . . . . 18
8.1. Authentication and Authorization . . . . . . . . . . . . . 18
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 19
9.1. Normative References . . . . . . . . . . . . . . . . . . . 19
9.2. Informative References . . . . . . . . . . . . . . . . . . 19
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 20
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1. Introduction
Communication Session recording requires establishment of the
recording session between communication system and recording system.
In order to allow access to such recordings, information about the
communication session (metadata) is also shared between SRC and SRS.
The SIPREC Requirements [I-D.ietf-siprec-req] list a set of
requirements that need to be met by session recording protocols. The
SIPREC protocol, which is specified in this document, meets these
requirements.
The SIPREC protocol uses SIP as the protocol for session
establishment with special attention to reducing size of the required
SIP messages. In addition, it is designed for future extendability
and protocol version management to ensure backward compatability.
The remainder of this document is organized as follows: Section 2
defines the terminology used throughout this document, Section 3
discusses the scope of SIPREC (i.e., which tasks fall within the
scope of SIPREC and which ones are performed using different
mechanisms), Section 4 provides a non-normative overview of SIPREC
operation, and subsequent sections provide the normative
specification of SIPREC.
2. Definitions
The core SIPREC defintions are taken from the requirements document
[I-D.ietf-siprec-req].
Session Recording Server (SRS): A Session Recording Server (SRS)
is a SIP User Agent (UA) that is a specialized media server or
collector that acts as the sink of the recorded media. An SRS is
a logical function that typically archives media for extended
durations of time and provides interfaces for search and retrieval
of the archived media. An SRS is typically implemented as a
multi-port device that is capable of receiving media from several
sources simultaneously. An SRS is typically also the sink of the
recorded session metadata.
Session Recording Client (SRC) A Session Recording Client (SRC) is a
SIP User Agent (UA) that acts as the source of the recorded media,
sending it to the SRS. An SRC is a logical function. Its
capabilities may be implemented across one or more physical
devices. In practice, an SRC could be a personal device (such as
a SIP phone), a SIP Media Gateway (MG), a Session Border
Controller (SBC) or a SIP Media Server (MS) integrated with an
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Application Server (AS). This specification defines the term SRC
such that all such SIP entities can be generically addressed under
one definition. The SRC itself or another entity working on its
behalf (such as a SIP Application Server) may act as the source of
the recording metadata.
Communication Session (CS) A session created between two or more SIP
User Agents (UAs) that is the target for recording.
Recording Session (RS) The SIP session created between an SRC and
SRS for the purpose of recording a Communication Session.
Metadata Information that describes recorded media and the CS to
which they relate.
SIPREC The set of SIP extensions that supports recording of
Communication Sessions.
Pause during a Communication Session: The action of temporarily
discontinuing the transmission and collection of RS media.
Resume during a Communication Session: The action of recommencing
the transmission and collection of RS media.
Figure 1 shows the relationship between the defintions.
+-------------+ +-----------+
| | Communication Session | |
| A |<------------------------------------>| B |
| | | |
+-------------+ +-----------+
..................................................................
. Session .
. Recording .
. Client .
..................................................................
|
| Recording
| Session
|
v
+------------+
| Session |
| Recording |
| Server |
+------------+
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Figure 1: Relationship between CS, SRC, SRS, and RS
3. Scope
The scope of the SIPREC protocol includes the establishment of the
recording sessions and the reporting of the metadata. The following
items, which is not an exhaustive list, do not represent the SIPREC
protcol itself and are considered out of the scope of the SIPREC
protocol:
o Recording policies that determine whether the CS should be
recorded
o Retention policies that determine how long a recording is stored
o Searching and accessing the recorded media and metadata
o Delivering recording session metadata through non-SIP mechanism
4. Overview of operations
This section is informative and provides a description of SIPREC
operations.
As mentioned in the architecture document
[I-D.ietf-siprec-architecture], there are a couple of types of call
flows based on the location of the Session Recording Client. The
following sample call flows provide a quick overview of the
operations between the SRC and the SRS.
4.1. Delivering recorded media
When the SRC is deployed as a B2BUA, the SRC can route call requests
from UA(A) to UA(B). As a SIP B2BUA, the SRC has access to the media
path between the user agents. When the SRC is aware that it should
be recording the conversation, the SRC may bridge the media between
UA(A) and UA(B). The SRC then establishes the Recording Session with
the SRS and sends replicated media towards the SRS.
An endpoint can also be acting as the SRC, and the endpoint itself
will be establishing the Recording Session to the SRS. Since the
endpoint has access to the media in the communication session, the
endpoint can send replicated media towards the SRS.
The following basic call flow shows the SRC establishing a recording
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session towards the SRS. The call flow is essentially identical when
the SRC is a B2BUA or as the endpoint itself.
UA A SRC UA B SRS
|(1)CS INVITE | | |
|------------->| | |
| |(2)CS INVITE | |
| |---------------------->| |
| | (3)OK | |
| |<----------------------| |
| (4)OK | | |
|<-------------| | |
| |(5)RS INVITE (CallId + Participants) with SDP |
| |--------------------------------------------->|
| | | (6)OK with SDP |
| |<---------------------------------------------|
|(7)CS RTP | | |
|=============>|======================>| |
|<=============|<======================| |
| |(8)RS RTP | |
| |=============================================>|
| |=============================================>|
|(9)CS BYE | | |
|------------->| | |
| |(10)CS BYE | |
| |---------------------->| |
| |(11)RS BYE | |
| |--------------------------------------------->|
| | | |
Figure 2: Basic Recording Call flow
4.2. Conference focus as an SRC
A conference focus may also act as an SRC since it has access to all
the media from each conference participant. In this example, a user
agent may REFER the conference focus to the SRS, and the SRC may
choose to mix media streams from all participants as a single media
stream towards the SRS. In order to tell the conference focus to
start a recording session to the SRS, the user agent can include the
srs feature tag in the Refer-To header as per [RFC4508].
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UA A Focus UA B SRS
| (SRC) | |
| | | |
| (already in a conference) | |
|<==================>|<==================>| |
|(1)REFER sip:Conf-ID Refer-To:<SRS>;srs | |
|------------------->| |
|(2)202 Accepted | |
|<-------------------| |
| (3)NOTIFY (Trying)| |
|<-------------------| |
|(4)200 OK | |
|------------------->| |
| |(5)INVITE Contact:Conf-ID;isfocus |
| |--------------------------------------->|
| | (6)200 OK |
| |<---------------------------------------|
| | (7)RTP (mixed or unmixed) |
| |=======================================>|
| (8)NOTIFY (OK) | |
|<-------------------| |
|(9)200 OK | |
|------------------->| |
Figure 3: Recording call flow - SRC as a conference focus
4.3. Delivering recording metadata
Certain metadata, such as the attributes of the recorded media
stream, are already included in the SDP of the recording session.
This information is reused as part of the metadata. The SRC may
provide an initial metadata snapshot about recorded media streams in
the initial INVITE content in the recording session. Subsequent
metadata updates can be represented as a stream of events in UPDATE
or reINVITE requests sent by the SRC. These metadata updates are
normally incremental updates to the initial metadata snapshot to
optimize on the size of updates, however, the SRC may also decide to
send a new metadata snapshot anytime.
The SRS also has the ability to sent a request to the SRC to request
to receive a new metadata snapshot update when the SRS fails to
understand the current stream of incremental updates for whatever
reason (ie. SRS gets a syntax/semantic error in metadata update, the
SRS crashes and restarts), and the SRS may attach a reason along with
the snapshot request. This request allows both SRC and SRS to
restart the states with a new metadata snapshot so that further
metadata incremental updates will be based on the latest metadata
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snapshot. The metadata snapshot request will be provided as an INFO
package [RFC6086] and sent as mid-dialog messages within the
recording session by the SRS.
SRC SRS
| |
|(1) INVITE (metadata snapshot) |
|---------------------------------------------------->|
| (2)200 OK |
|<----------------------------------------------------|
|(3) ACK |
|---------------------------------------------------->|
|(4) RTP |
|====================================================>|
|(5) UPDATE (metadata update 1) |
|---------------------------------------------------->|
| (6) 200 OK |
|<----------------------------------------------------|
|(7) UPDATE (metadata update 2) |
|---------------------------------------------------->|
| (8) 200 OK |
|<----------------------------------------------------|
| (9) INFO (metadata snapshot request) |
|<----------------------------------------------------|
| (10) 200 OK |
|---------------------------------------------------->|
|(11) UPDATE (metadata snapshot 2) |
|---------------------------------------------------->|
| (12) 200 OK |
|<----------------------------------------------------|
|(13) UPDATE (metadata update 1 based on snapshot 2) |
|---------------------------------------------------->|
| (14) 200 OK |
|<----------------------------------------------------|
Figure 4: Delivering metadata via SIP INFO
In some cases session metadata can be conveyed through non-SIP
mechanism such as HTTP or JTAPI. These non-SIP mechanisms are
considered out of the scope of the SIPREC protocol, however, it is
envisoned that a link with a URI can be provided in the recording
session INVITE message so that the SRS can access the session
metadata via the URI provided that the SRS supports the type of URI.
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5. SIP Extensions for Recording Session
The following sections describe SIP extensions for the Recording
Session.
The From header must contain the identity of the SRC. Participants
information is not recorded in the From or To header; they are
included in the metadata information.
Note that a recording session does not have to have live within the
scope of a single communication session. As outline in REQ-005 of
[I-D.ietf-siprec-req], the recording session can be established in
the absence of a communication session. In this case, the SRC must
offer an SDP with zero m= lines.
Recorded media from multiple communication sessions may be handled in
a single recording session. The SRC provides a reference of each
recorded media stream to the metadata described in the next section.
The SRC must be able to accept re-INVITE from SRS with the updated
SDP as part of the session timer mechanism.
5.1. Callee Capabilities Extensions for SIP Recording
This section discusses how the callee capabilities defined in
[RFC3840] can be extended for SIP call recording.
SIP Callee Capabilities defines feature tags which are used to
represent characteristics and capabilities of a UA. From RFC 3840:
"Capability and characteristic information about a UA is carried
as parameters of the Contact header field. These parameters can
be used within REGISTER requests and responses, OPTIONS responses,
and requests and responses that create dialogs (such as INVITE)."
Note that feature tags are also used in dialog modifying requests and
responses such as re-INVITE and responses to a re-INVITE, and UPDATE.
The 'isfocus' feature tag, defined in [RFC4579] is similar
semantically to this case: it indicates that the UA is acting as a
SIP conference focus, and is performing a specific action (mixing) on
the resulting media stream. This information is available from
OPTIONS queries, dialog package notifications, and the SIP
registration event package.
We propose the definition of two new feature tags: 'src' and 'srs'.
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5.1.1. src Feature Tag
The 'src' feature tag is used in Contact URIs by the Session
Recording Client (SRC) related to recording sessions. A Session
Recording Server uses the presence of this feature tag in dialog
creating and modifying requests and responses to confirm that the
dialog being created is for the purpose of a Recording Session. In
addition, a registrar could discover that a UA is an SRC based on the
presence of this feature tag in a registration. Other SIP Recording
extensions and behaviors can be triggered by the presence of this
feature tag.
Note that we could use a single feature tag, such as 'recording' used
by either an SRC or SRS to identify that the session is a recording
session. However, due to the differences in functionality and
behavior between an SRC and SRS, using only one feature tag for both
is not ideal. For instance, if a routing mistake resulted in a
request from a SRC being routed back to another SRC, if only one
feature tag were defined, they would not know right away about the
error and could become confused. With separate feature tags, they
would realize the error immediately and terminate the session. Also,
call logs would clearly show the routing error.
5.1.2. srs Feature Tag
The 'srs' feature tag is used in Contact URIs by the Session
Recording Server (SRS) related to recording sessions. A Session
Recording Client uses the presence of this feature tag in dialog
creating and modifying requests and responses to confirm that the
dialog being created is for the purpose of a Recording Session
(REQ-30). In addition, a registrar could discover that a UA is an
SRS based on the presence of this feature tag in a registration.
Other SIP Recording extensions and behaviors can be triggered by the
presence of this feature tag.
To ensure a recording session is redirected to an SRS, an SRC can
utilize the SIP Caller Preferences extensions, defined in [RFC3841].
The presence of a Accept-Contact: *;sip.srs allows a UA to request
that the INVITE be routed to an SRS. Note that to be completely
sure, the SRC would need to include a Require: prefs header field
field in the request.
5.2. SDP handling
SRC can include one or more media streams to the SRS. The SRS must
respond with the same number of media descriptors in the SDP body of
the 200 OK.
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The SRC should use a=sendonly attribute as the SRC does not expect to
receive media from the SRS. As SRS only receives RTP streams from
SRS, the 200 OK response will normally contain SDP with a=recvonly
attribute.
Since the SRC may send recorded media of different participants (or
even mixed streams) to the SRS, the SDP must provide a label on each
media stream in order to identify the recorded stream with the rest
of the metadata. The a=label attribute [RFC4574] will be used to
identify each recorded media stream, and the label name will be used
as the reference for the metadata. Note that a participant may have
multiple streams (audio and video) and each stream is labeled
separately.
v=0
o=SRS 0 0 IN IP4 172.22.3.8
s=SRS
c=IN IP4 172.22.3.8
t=0 0
m=audio 12241 RTP/AVP 0 4 8
a=sendonly
a=label:1
m=audio 12242 RTP/AVP 98
a=rtpmap:98 H264/90000
a=fmtp:98 ...
a=sendonly
a=label:2
m=audio 12243 RTP/AVP 0 4 8
a=sendonly
a=label:3
m=audio 12244 RTP/AVP 98
a=rtpmap:98 H264/90000
a=fmtp:98 ...
a=sendonly
a=label:4
Figure 6: Sample SDP with audio and video streams
To remove a recorded media stream from the recording session, send a
reINVITE and set the port to zero in the m= line.
To add a recorded media stream, send a reINVITE and add a new m=
line.
The SRS may respond with a=inactive attribute as part of the SDP in
the 200 OK response when the SRS is not ready to receive recorded
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media. The SRS can send re-INVITE to update the SDP with a=recvonly
when it is ready to receive media.
The following sequence diagram shows an example of SRS responds with
SDP that contain a=inactive, and then later update media information
update with re-INVITE.
SRC SRS
| |
|(1) INVITE (no offer) |
|---------------------------------------------------->|
| (2)200 OK with SDP inactive |
|<----------------------------------------------------|
|(3) ACK with SDP inactive |
|---------------------------------------------------->|
| ... |
| (4) re-INVITE with SDP recvonly |
|<----------------------------------------------------|
|(5)200 OK with SDP sendonly |
|---------------------------------------------------->|
| (6) ACK with SDP |
|<----------------------------------------------------|
|(7) RTP |
|====================================================>|
| ... |
|(8) BYE |
|---------------------------------------------------->|
| (9) OK |
|<----------------------------------------------------|
Figure 7: SRS to offer with a=inactive
5.3. Metadata
The format of the full metadata will be described as part of the
mechanism in [I-D.ram-siprec-metadata].
As mentioned in the previous section, the SDP of the recording
session is the metadata for all recorded media streams. The label
attribute contains a reference to the rest of the metadata
information.
For all basic metadata information such as communication session,
participants, call identifiers and direction, they can be included in
the initial INVITE request sent by the SRC. Metadata can be included
as content in the INVITE or UPDATE request. A new "disposition-type"
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of Content-Disposition is defined for this purpose and the value is
"recording-session".
The following SIP example for RS establishment between SRC and SRS
with metadata as content.
INVITE sip:97753210@10.240.3.10:5060 SIP/2.0
From: <sip:2000@10.226.240.3>;tag=35e195d2-947d-4585-946f-098392474
To: <sip:Recorder@10.240.3.10>
Call-ID: d253c800-b0d1ea39-4a7dd-3f0e20a@10.226.240.3
CSeq: 101 INVITE
Date: Thu, 26 Nov 2009 02:38:49 GMT
Supported: timer
Supported: replaces
User-Agent: B2BUA
Max-Forwards: 70
Allow: INVITE,OPTIONS,INFO,BYE,CANCEL,ACK,PRACK,UPDATE,
REFER,SUBSCRIBE,NOTIFY,PUBLISH
Allow-Events: presence,kpml
Min-SE: 90
Contact: <sip:2000@10.226.240.3:5060;transport=tcp>;isfocus;src
Via: SIP/2.0/TCP 10.226.240.3:5060;branch=z9hG4bKdf6b622b648d9
Session-Expires: 1800
Content-Type: multipart/mixed;boundary=foobar
Content-Length: [length]
--foobar
Content-Type: application/sdp
v=0
o=SRS 0 0 IN IP4 10.226.240.3
c=IN IP4 10.226.240.3
t=0 0
m=audio 12241 RTP/AVP 0 4 8
a=sendonly
a=label:1
--foobar
Content-Type: application/rs-metadata
Content-Disposition: recording-session
[metadata content]
Figure 8: Sample INVITE request for the recording session
Further updates to recording metadata can be deliverd as a sequence
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events reported in SIP UPDATE or reINVITE requests and the SRS must
receive the sequence of events in order. Since there can only be a
single INVITE or UPDATE transaction happening at a time within a SIP
dialog, using sequence number CSeq in the dialog can be a reliable
way for the SRS to identify the receipt of the next metadata update.
At any time during Recording Session, the SRC may send a new metadata
snapshot in SIP UPDATE or reINVITE request. All subsequent metadata
updates will be based on the new metadata snapshot.
5.3.1. Requesting for metadata snapshot
The SRS may send an INFO request to request for a metadata snapshot
any time after the Recording Session has been established. The INFO
package is "recording-session-srs". The format of the metadata
snapshot request is described in [I-D.ram-siprec-metadata]. This
request allows the SRS to request for a metadata snapshot from the
SRC, and is used in scenarios where the SRS is failing to process
further metadata incremental updates. Failure scenarios can include
failure to parse metadata information (syntax error), failure to
match metadata information with the current metadata snapshot
(semantic error), or failure at the SRS. The SRS should include the
reason why a snapshot request is being made.
When the SRC receives the INFO request for a metadata snapshot, the
SRC should wait for any existing dialog modifying transactions to
complete and then send a UPDATE request with a new metadata snapshot.
All subsequent metadata updates sent by the SRC will be based on the
new metadata snapshot.
5.3.2. Recording Pause and Resume
To temporarily discontinue streaming and collection of recorded media
from the SRC to the SRS, the SRC must send a reINVITE and set
a=inactive for each recorded media stream to be paused.
To resume streaming and collection of recorded media, the SRC must
send a reINVITE and set a=sendonly for each recorded media stream to
resume.
Note that when a media stream in the CS is muted/unmuted, this
information may conveyed in the metadata by the SRC. The SRC should
not modify the recorded media stream with a=inactive for mute since
this operation is reserved for pausing the RS media.
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6. SIP Extensions for Recording-aware User Agents
The following sections describe SIP extensions for recording-aware
UA.
6.1. Recording awareness
A recording-aware UA MUST include the 'a=recording-aware' SDP
attribute to indicate that the user agent can accept other recording
SDP attributes listed in this section. This is a session level
attribute.
If the offerer is recording-aware and the answerer is also recording-
aware, the answer MUST contain the recording-aware attribute.
If the offerer is not recording-aware, the answerer MUST be prepared
to provide recording indication through other existing mechanisms
such as in-band media.
6.2. Providing recording indication
While there are existing mechanisms for providing an indication that
a CS is being recorded, these mechanisms are usually delivered on the
CS media streams such as playing an in-band tone or an announcement
to the participants. A new SDP attribute is introduced to allow a
recording-aware UA to render recording indication at the user
interface.
The 'record' SDP attribute may appear at the session level or the
media level, and may appear in either SDP offer or answer. When the
attribute is set at the session level, then the recording indication
applies to all media streams within the session. When the attribute
is set at the media level, then the recording indication applies to
the specified media stream only. The following is the ABNF of the
'record' attribute:
record-attr = "a=record:" indication
indication = "on" / "off" / "paused"
on Recording is in progress.
off No recording is in progress.
paused Recording is in progress by media is paused.
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6.3. Recording preference
A recording-aware UA involved in a CS may request the CS to be
recorded or not recorded. This indication of recording preference
may be sent at session establishment time or during the session.
A new SDP attribute "recordpref" is introduced. The SDP attribute
may appear at the session level or the media level and can only
appear in an SDP offer. When the attribute is set at the session
level, then the recording indication applies to all media streams
within the session. When the attribute is set at the media level,
then the recording indication applies to the specified media stream
only. The following is the ABNF of the recordpref attribute:
recordpref-attr = "a=recordpref:" pref
pref = "record" / "norecord" / "pause" / "resume"
record Request for recording if it has not already been started.
norecord Request for no recording. If recording has already been
started, then this preference indicates a request to stop
recording.
pause Request to pause recording if recording is currently in
progress.
resume Request to resume recording if recording is currently paused.
7. IANA Considerations
7.1. New Content-Disposition Parameter Registrations
This document registers a new "disposition-type" value in Content-
Disposition header: recording-session.
recording-session the body describes the metadata information about
the recording session
7.2. Media Type Registration
7.2.1. Registration of MIME Type application/rs-metadata
This document registers the application/rs-metadata MIME media type
in order to describe the recording session metadata. This media type
is defined by the following information:
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Media type name: application
Media subtype name: rs-metadata
Required parameters: none
Options parameters: none
7.2.2. Registration of MIME Type application/rs-metadata-request
This document registers the application/rs-metadata-request MIME
media type in order to describe a recording session metadata snapshot
request. This media type is defined by the following information:
Media type name: application
Media subtype name: rs-metadata-request
Required parameters: none
Options parameters: none
7.3. Info Package
This document registers a new INFO package for transpoting metadata
requests from the SRS within a Recording Session.
Info Package Name: recording-session-srs
Reference: [RFCXXXX]
7.4. SDP Attributes
This document registers the following new SDP attributes.
7.4.1. 'recording-aware' SDP Attribute
Attribute name: recording-aware
Type of attribute: session level
Subject to charset: no
This attribute indicates that the user agent supports recording
extensions. This is a property attribute which does not take a
value.
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7.4.2. 'record' SDP Attribute
Attribute name: record
Long form attribute name: Recording Indication
Type of attribute: session level or media level
Subject to charset: no
This attribute provides the recording indication for the session or
media stream.
Allowed attribute values: on, off, paused
7.4.3. 'recordpref' SDP Attribute
Attribute name: recordpref
Long form attribute name: Recording Preference
Type of attribute: session level or media level
Subject to charset: no
This attribute provides the recording indication for the session or
media stream.
Allowed attribute values: nopref, record, norecord, pause, resume
8. Security Considerations
The recording session is fundamentally a standard SIP dialog
[RFC3261], therefore, the recording session can reuse any of the
existing SIP security mechanism available for securing the recorded
media as well as metadata.
8.1. Authentication and Authorization
The recording session reuses the SIP mechanism to challenge requests
that is based on HTTP authentication. The mechanism relies on 401
and 407 SIP responses as well as other SIP header fields for carrying
challenges and credentials.
The SRS may have its own set of recording policies to authorize
recording requests from the SRC. The use of recording policies is
outside the scope of the SIPREC protocol.
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9. References
9.1. Normative 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-06 (work in progress),
December 2010.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2804] IAB and IESG, "IETF Policy on Wiretapping", RFC 2804,
May 2000.
[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.
[RFC3265] Roach, A., "Session Initiation Protocol (SIP)-Specific
Event Notification", RFC 3265, June 2002.
[RFC3840] Rosenberg, J., Schulzrinne, H., and P. Kyzivat,
"Indicating User Agent Capabilities in the Session
Initiation Protocol (SIP)", RFC 3840, August 2004.
[RFC3841] Rosenberg, J., Schulzrinne, H., and P. Kyzivat, "Caller
Preferences for the Session Initiation Protocol (SIP)",
RFC 3841, August 2004.
[RFC4574] Levin, O. and G. Camarillo, "The Session Description
Protocol (SDP) Label Attribute", RFC 4574, August 2006.
[RFC6086] Holmberg, C., Burger, E., and H. Kaplan, "Session
Initiation Protocol (SIP) INFO Method and Package
Framework", RFC 6086, January 2011.
9.2. Informative References
[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]
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R, R., R, P., and P. Kyzivat, "Session Initiation Protocol
(SIP) Recording Metadata", draft-ram-siprec-metadata-03
(work in progress), January 2011.
[RFC4508] Levin, O. and A. Johnston, "Conveying Feature Tags with
the Session Initiation Protocol (SIP) REFER Method",
RFC 4508, May 2006.
[RFC4579] Johnston, A. and O. Levin, "Session Initiation Protocol
(SIP) Call Control - Conferencing for User Agents",
BCP 119, RFC 4579, August 2006.
Authors' Addresses
Leon Portman (editor)
NICE Systems
8 Hapnina
Ra'anana 43017
Israel
Email: leon.portman@nice.com
Henry Lum
Genesys, Alcatel-Lucent
1380 Rodick Road, Suite 200
Markham, Ontario L3R4G5
Canada
Email: henry.lum@genesyslab.com
Alan Johnston
Avaya
St. Louis, MO 63124
Email: alan.b.johnston@gmail.com
Andrew Hutton
Siemens Enterprise Communications
Email: andrew.hutton@siemens-enterprise.com
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