SIPREC L. Portman, Ed.
Internet-Draft NICE Systems
Intended status: Informational H. Lum
Expires: July 21, 2011 Genesys, Alcatel-Lucent
A. Johnston
Avaya
A. Hutton
Siemens Enterprise Communications
January 17, 2011
The SIP-based Media Recording Protocol (SIPREC)
draft-portman-siprec-protocol-02
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
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on July 21, 2011.
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document authors. All rights reserved.
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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. Delivering recording metadata . . . . . . . . . . . . . . 7
5. SIP Extensions . . . . . . . . . . . . . . . . . . . . . . . . 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. Delivering Metadata as a stream of events . . . . . . 14
5.3.1.1. Example - indication for which the SRS is
willing to receive INFO Package . . . . . . . . . 14
5.4. Recording Pause and Resume . . . . . . . . . . . . . . . . 16
6. Transport . . . . . . . . . . . . . . . . . . . . . . . . . . 16
7. Failover and Recovery . . . . . . . . . . . . . . . . . . . . 16
8. Error Handling . . . . . . . . . . . . . . . . . . . . . . . . 16
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
9.1. New Content-Disposition Parameter Registrations . . . . . 16
9.2. MIME Type . . . . . . . . . . . . . . . . . . . . . . . . 17
9.3. Info Package . . . . . . . . . . . . . . . . . . . . . . . 17
10. Security Considerations . . . . . . . . . . . . . . . . . . . 17
10.1. Authentication and Authorization . . . . . . . . . . . . . 17
10.2. Privacy of metadata . . . . . . . . . . . . . . . . . . . 18
11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 18
11.1. Normative References . . . . . . . . . . . . . . . . . . . 18
11.2. Informative References . . . . . . . . . . . . . . . . . . 19
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19
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1. Introduction
Communication session recording requires establishment of a recording
session (RS) between a session recording client (SRC) and session
recording server (SRS). The overall architecture for media recording
is described in the architecture draft [I-D.ietf-siprec-architecture]
The SIPREC Requirements [I-D.ietf-siprec-req] list a set of
requirements that need to be met by session recording protocols. SIP
is chosen to be the protocol to establish the recording session to
deliver recorded media to the session recording server. Additional
SIP extensions are specified in this document to meet some of the
requirements outlined in the requirements draft.
In order to describe the recorded media and the communication
sessions involved, a metadata model is described in
[I-D.ram-siprec-metadata] to deliver additional information shared
between SRC and SRS.
2. Definitions
The core SIPREC definitions 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
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.
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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.
Figure 1 pictorially represents the relationship between a
Recording Session and Communication Session.
+-------------+ +-----------+
| | Communication Session | |
| A |<------------------------------------>| B |
| | | |
+-------------+ +-----------+
..................................................................
. Session .
. Recording .
. Client .
..................................................................
|
| Recording
| Session
|
v
+------------+
| Session |
| Recording |
| Server |
+------------+
Figure 1: Relationship between CS, SRC, SRS, and RS
Metadata Information that describes recorded media and the CS to
which they relate.
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.
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3. Scope
The scope of the SIPREC protocol includes the establishment of the
recording sessions and the reporting of the metadata, and extensions
to the communication sessions.
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 protcol:
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 SDP
and therefore can manipulate 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 act as the SRC, and in this case may establish 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
session towards the SRS. The call flow is essentially identical when
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the SRC is a B2BUA or as the endpoint itself.
UA A B2BUA UA B SRS
| (SRC) | |
|(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
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
4.2. 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
update or add additional metadata about recorded media streams in
requests such as INVITE, reINVITE, and UPDATE in the Recording
Session.
The rest of the metadata will be delivered as content. Metadata can
also be represented as a stream of events. There are 4 ways to
transport metadata events as outlined in the architecture document:
SIP INVITE Content: for a simple call recording use case where no
mid-dialog events are required to be delivered after the RS is
established, the SIP INVITE may include content for all the metadata
needed for the call.
SIP INFO Package: metadata can be provided as an INFO package
[I-D.ietf-sipcore-info-events] and sent as mid-dialog messages within
the recording session.
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UA A UA B SRS
(SRC) | |
|(1)CS INVITE | |
|---------------------->| |
| (2)OK | |
|<----------------------| |
|(3)RS INVITE (SDP) | |
|--------------------------------------------->|
| | (4)OK with SDP |
|----------------------------------------------|
|(5)CS RTP | |
|======================>| |
|<======================| |
|(6)RS RTP | |
|=============================================>|
|=============================================>|
|(7)RS INFO (metadata) | |
|--------------------------------------------->|
|(8)CS BYE | |
|---------------------->| |
|(9)RS BYE | |
|--------------------------------------------->|
| | |
Figure 4: Delivering metadata via SIP INFO
[OPEN ISSUE: is Event Package desired?]
Event Package: Metadata can also be conveyed from the SRC to the SRS
using the SIP event notification mechanism [RFC3265]. Using a
subscription allows the SRC to deliver metadata to the SRS when the
lifecycles of the CS and RS are different. This also allows the SRC
to deliver session metadata and recorded media separately, for
example, an SRS that reports metadata for multiple recording sessions
as a single subscription.
Non-SIP transport: 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 envisioned 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
The following sections describe SIP extensions for the recording
protocol.
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 request. A new "disposition-type" of
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Content-Disposition is defined for this purpose and the value is
"recording-session". There is a single payload type "application/
rs-metadata" defined for recording metadata.
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
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5.3.1. Delivering Metadata as a stream of events
Recording metadata can delivered as a stream of events. For this
case, the metadata events is reported as SIP INFO messages within the
recording session. INFO Package is chosen as the mechanism because
the metadata events does not always have to be associated with
changes to the recorded media that requires the use of a reINVITE.
For example, when a new participant is joined to a recorded
conference and the SRS is receiving the recorded media as a mixed
audio stream, then there is no need to send a reINVITE update the
recorded media; an INFO message with the necessary metadata to
describe the new participant is sufficient information for the SRS.
The Info Package name is "recording-session". This name is used in
both the Info-Package header as well as the Recv-Info header fields.
The SRS must set the Recv-Info header to indicate that it is willing
to receive INFO requests for Info Package recording-session. The SRC
is not required to set the Recv-Info header since it does not expect
to receive any Info Package from the SRS.
There is only a single payload type "application/rs-metadata" defined
for the Info Package. Similar to the metadata format for INVITE
requests, the metadata format is defined in
[I-D.ram-siprec-metadata].
This Info Package does not impose any rate limit or throttling
mechansim for the stream of metadata events. A recording session is
not expect to emit a high rate of metadata events, however, there are
scenarios where there can be short bursts metadata events generated.
For example, when a scheduled conference is being recorded, there can
be a burst of participants joining the conference at the scheduled
time and hence a burst of metadata update to the communication
session.
5.3.1.1. Example - indication for which the SRS is willing to receive
INFO Package
The SRC initiates a recording session and indicates that it is the
SRC.
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INVITE sip:srs@example.com SIP/2.0
Via: SIP/2.0/TCP src12.example.com;branch=z9hG4bKdf6b622b648d9
From: <sip:src@example.com>;tag=35e195d2
To: <sip:srs@example.com>
Call-ID: d253c800-b0d1ea39-4a7dd-3f0e20a@10.226.240.3
CSeq: 101 INVITE
Contact: <sip:src12.example.com>;src
Content-Type: multipart/mixed;boundary=foobar
Content-Length: ...
...
The SRS sends a 200 OK response and indicate that it is willing to
receive metadata Info Package
SIP/2.0 200 OK
Via: SIP/2.0/TCP src12.example.com;branch=z9hG4bKdf6b622b648d9
From: <sip:src@example.com>;tag=35e195d2
To: <sip:srs@example.com>;tag=12345678
Call-ID: d253c800-b0d1ea39-4a7dd-3f0e20a@10.226.240.3
CSeq: 101 INVITE
Contact: <sip:srs07.example.com>;srs
Recv-Info: recording-session
Content-Type: application/sdp
Content-Length: ...
...
After the recording session is established, the SRC sends an INFO
request to the SRS to indicate participant changes to the
communication session.
INFO sip:srs07.example.com SIP/2.0
Via: SIP/2.0/TCP src12.example.com;branch=z9hG4bKdf6b622abcd
From: <sip:src@example.com>;tag=35e195d2
To: <sip:srs@example.com>;tag=12345678
Call-ID: d253c800-b0d1ea39-4a7dd-3f0e20a@10.226.240.3
CSeq: 102 INFO
Contact: <sip:src12.example.com>;src
Info-Package: recording-session
Content-Type: application/rs-metadata
Content-Disposition: Info-Package
Content-Length: ...
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[metadata content]
5.4. 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.
6. Transport
TBD
7. Failover and Recovery
TBD
8. Error Handling
For handling errors with session establishment of the recording
session, error handling of a standard SIP dialog applies.
For handling errors with the metadata content such as syntactic or
semantic errors, it is possible to introduce another Info content as
a response to each metadata content sent by the SRS in order to allow
the SRS to posivitively or negatively acknowledge each metadata
content. [TBD - need to sync with metadata draft]
9. IANA Considerations
9.1. New Content-Disposition Parameter Registrations
This document registers a new "disposition-type" value in Content-
Disposition header: recording-session.
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recording-session the body describes the metadata information about
the recording session
9.2. MIME Type
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:
Media type name: application
Media subtype name: rs-metadata
Required parameters: none
Options parameters: none
9.3. Info Package
This document registers a new INFO package for transpoting recording
session metadata.
Info Package Name: recording-session
Reference: [RFCXXXX]
10. 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.
10.1. 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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10.2. Privacy of metadata
Since metadata is transported as content in SIP messages such as
INVITE and INFO Packages, the requests can be routed through SIP
proxies between the SRC and SRS. If the metadata content is
considered private, then the SRC and SRS will need to use end-to-end
encryption such as S/MIME in addition to hop-by-hop security (SIP/
TLS) to prevent access by proxies or B2BUAs.
11. References
11.1. 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.
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11.2. Informative References
[I-D.ietf-sipcore-info-events]
Holmberg, C., Burger, E., and H. Kaplan, "Session
Initiation Protocol (SIP) INFO Method and Package
Framework", draft-ietf-sipcore-info-events-10 (work in
progress), October 2010.
[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-02
(work in progress), December 2010.
[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
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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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