SIPREC L. Portman, Ed.
Internet-Draft NICE Systems
Intended status: Informational H. Lum
Expires: November 4, 2011 Genesys, Alcatel-Lucent
A. Johnston
Avaya
A. Hutton
Siemens Enterprise
Communications
May 3, 2011
Session Recording Protocol
draft-portman-siprec-protocol-04
Abstract
The Session Recording Protocol is used for establishing recording
session and reporting of the metadata of the communication session.
This document specifies the Session Recording Protocol. The protocol
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
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This Internet-Draft will expire on November 4, 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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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 . . . . . . . . . . . . . 8
5.1. Callee Capabilities Extensions for SIP Recording . . . . . 9
5.1.1. src Feature Tag . . . . . . . . . . . . . . . . . . . 9
5.1.2. srs Feature Tag . . . . . . . . . . . . . . . . . . . 10
5.2. SDP handling . . . . . . . . . . . . . . . . . . . . . . . 10
5.3. RTP handling . . . . . . . . . . . . . . . . . . . . . . . 12
5.4. Metadata . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.4.1. Requesting for metadata snapshot . . . . . . . . . . . 14
5.4.2. Recording Pause and Resume . . . . . . . . . . . . . . 14
6. SIP Extensions for Recording-aware User Agents . . . . . . . . 15
6.1. Providing recording indication . . . . . . . . . . . . . . 15
6.2. Recording awareness . . . . . . . . . . . . . . . . . . . 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. Registration of record-aware Option Tag . . . . . . . . . 17
7.4. SDP Attributes . . . . . . . . . . . . . . . . . . . . . . 17
7.4.1. 'record' SDP Attribute . . . . . . . . . . . . . . . . 17
7.4.2. 'recordpref' SDP Attribute . . . . . . . . . . . . . . 18
8. Security Considerations . . . . . . . . . . . . . . . . . . . 18
8.1. Authentication and Authorization . . . . . . . . . . . . . 18
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 18
9.1. Normative References . . . . . . . . . . . . . . . . . . . 18
9.2. Informative References . . . . . . . . . . . . . . . . . . 19
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 20
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1. Introduction
Communication Session (CS) recording requires establishment of the
recording session between communication system and recording system.
In order to allow access to such recordings, the metadata about the
CS shall be sent from the SRC to the SRS.
The SIP-based Media Recording Requirements [I-D.ietf-siprec-req] list
a set of requirements that need to be met by session recording
protocols. The Session Recording Protocol, which is specified in
this document, meets these requirements.
The Session Recording 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 the Session Recording Protocol, Section 4
provides a non-normative overview of recording operations, Section 5
provides normative description of SIP extensions for the Recording
Session, Section 6 provides normative description of SIP extensions
for recording-aware user agents.
2. Definitions
The core 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.
Session Recording Protocol 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 Session Recording 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 protcol itself and are considered out of the scope
of the Session Recording 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 recording
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 is a sample call flow that shows the SRC establishing a
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recording session towards the SRS. The call flow is essentially
identical when the SRC is a B2BUA or as the endpoint itself. Note
that the SRC can choose when to establish the Recording Session
independent of the Communication Session, even though the following
call flow suggests that the Recording Session is esbalished after the
Communication Session is estbablished.
UA A SRC UA B SRS
|(1)CS INVITE | | |
|------------->| | |
| |(2)CS INVITE | |
| |---------------------->| |
| | (3)OK | |
| |<----------------------| |
| (4)OK | | |
|<-------------| | |
| |(5)RS INVITE 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)RS 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. Similar to the metadata content, the metadata snapshot
request is transported as content in UPDATE or INVITE sent by the SRS
in the recording session.
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) UPDATE (metadata snapshot request) |
|<----------------------------------------------------|
| (10) 200 OK (metadata snapshot 2) |
|---------------------------------------------------->|
|(11) UPDATE (metadata update 1 based on snapshot 2) |
|---------------------------------------------------->|
| (12) 200 OK |
|<----------------------------------------------------|
Figure 4: Delivering metadata via SIP UPDATE
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 Session Recording 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.
5. SIP Extensions for Recording Session
The following sections describe SIP extensions for the Recording
Session.
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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 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.
Note that a recording session does not have to 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.
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'.
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
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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
Following the SDP offer/answer model in [RFC3264], this section
describes the conventions used in the recording session for 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
SRC, 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. RTP handling
[This is a placeholder section to specify protocol impacts to support
different RTP models in the session recording protocol.]
5.4. Metadata
The format of the full metadata will be described as part of the
mechanism in [I-D.ram-siprec-metadata-format].
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.
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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"
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]
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Figure 8: Sample INVITE request for the recording session
Further updates to recording metadata can be deliverd as a sequence
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.
5.4.1. Requesting for metadata snapshot
The SRS may send a request for metadata snapshot any time after the
Recording Session has been established. Similar to delivering
metadata, the SRS sends the metadata snapshot request as content in
UPDATE or INVITE requests or responses. The same disposition type
"recording-session" is used to note that the content represents
content sent by the SRS. The format of the metadata snapshot request
is described in [I-D.ietf-siprec-metadata].
The SRS should include the reason why a metadata snapshot request is
being made to the SRC. Typically, the SRS sends such as request in
the case 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.
When the SRC receives the request for a metadata snapshot, the SRC
may provide the metadata snapshot in the response or as a separate
INVITE/UPDATE transaction. All subsequent metadata updates sent by
the SRC MUST be based on the new metadata snapshot.
5.4.2. 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
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information may be 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.
6. SIP Extensions for Recording-aware User Agents
The following sections describe SIP extensions for recording-aware
UA.
6.1. 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 appears at the media level, and may appear
in either SDP offer or answer. The recording indication applies to
the specified media stream only, for example, the audio portion of
the call may be recorded in a audio/video call. 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.
6.2. Recording awareness
A recording-aware UA may indicate that it can accept reporting of
recording indication in media level SDP provided in the previous
section. A new option tag "record-aware" is introduced to indicate
such awareness.
When a user agent inserts a Supported header field with the option
tag record-aware, the UAS may provide recording indications through
the media level SDP. The UAS may also at the same time provide
recording indications through traditional means such as playing a
tone inband.
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When a user agent inserts a Require header field with the option tag
record-aware, the UAS MUST only provide recording indications through
the media level SDP.
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
appears at the media level and can only appear in an SDP offer. 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 = "on" / "off" / "pause"
on Request for recording if it has not already been started. If the
recording is currently paused, request to resume recording.
off 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.
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. Registration of record-aware Option Tag
This document registers the "record-aware" option tag.
Name: record-aware
Description: This option tag is to indicate the ability for the user
agent to receive recording indicators in media level SDP. When
present in a Supported header, it indicates that the UA can receive
recording indicators in media level SDP. When present in a Require
header, it indicates that the UAS MUST send all recording indicators
through media level SDP only and not through inband media.
7.4. SDP Attributes
This document registers the following new SDP attributes.
7.4.1. 'record' SDP Attribute
Attribute name: record
Long form attribute name: Recording Indication
Type of attribute: media level
Subject to charset: no
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This attribute provides the recording indication for the session or
media stream.
Allowed attribute values: on, off, paused
7.4.2. 'recordpref' SDP Attribute
Attribute name: recordpref
Long form attribute name: Recording Preference
Type of attribute: media level
Subject to charset: no
This attribute provides the recording indication for the session or
media stream.
Allowed attribute values: on, off, pause
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 Session Recording Protocol.
9. References
9.1. Normative References
[I-D.ietf-siprec-req]
Rehor, K., Portman, L., Hutton, A., and R. Jain, "Use
Cases and Requirements for SIP-based Media Recording
(SIPREC)", draft-ietf-siprec-req-09 (work in progress),
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March 2011.
[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.
[RFC3264] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model
with Session Description Protocol (SDP)", RFC 3264,
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-02
(work in progress), April 2011.
[I-D.ietf-siprec-metadata]
R, R., R, P., and P. Kyzivat, "Session Initiation Protocol
(SIP) Recording Metadata", draft-ietf-siprec-metadata-00
(work in progress), April 2011.
[I-D.ram-siprec-metadata-format]
R, R., R, P., and P. Kyzivat, "Session Initiation Protocol
(SIP) Recording Metadata Format",
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draft-ram-siprec-metadata-format-01 (work in progress),
March 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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