SIPREC K. Rehor, Ed.
Internet-Draft Cisco Systems
Intended status: Informational L. Portman, Ed.
Expires: November 4, 2011 NICE Systems
A. Hutton
Siemens Enterprise
Communications
R. Jain
IPC Systems
May 03, 2011
Use Cases and Requirements for SIP-based Media Recording (SIPREC)
draft-ietf-siprec-req-10
Abstract
Session recording is a critical requirement in many business
communications environments such as call centers and financial
trading floors. In some of these environments, all calls must be
recorded for regulatory and compliance reasons. In others, calls may
be recorded for quality control or business analytics.
Recording is typically performed by sending a copy of the session
media to the recording devices. This document specifies requirements
for extensions to SIP that will manage delivery of RTP media to a
recording device. This is being referred to as SIP-based Media
Recording.
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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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 November 4, 2011.
Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Requirements notation . . . . . . . . . . . . . . . . . . . . 4
3. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 10
6. Privacy Considerations . . . . . . . . . . . . . . . . . . . . 12
7. Security Considerations . . . . . . . . . . . . . . . . . . . 13
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 14
10. Normative References . . . . . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15
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1. Introduction
Session recording is a critical operational requirement in many
businesses, especially where voice is used as a medium for commerce
and customer support. A prime example where voice is used for trade
is the financial industry. The call recording requirements in this
industry are quite stringent. The recorded calls are used for
dispute resolution and compliance. Other businesses such as customer
support call centers typically employ call recording for quality
control or business analytics, with different requirements.
Depending on the country and its regulatory requirements, financial
trading floors typically must record all calls. In contrast, call
centers typically only record a subset of the calls, and calls must
not fail regardless of the availability of the recording device.
Respecting the privacy rights and wishes of users engaged in a call
is of paramount importance. In many jurisdictions participants have
a right to know that the session is being recorded or might be
recorded, and have a right to opt out, either by terminating the call
or by demanding that the call not be recorded. Therefore this
document contains requirements for being able to notify users that a
call is being recorded and for users to be able to request that a
call not be recorded. Use cases where users participating in a call
are not informed that the call is or might be recorded are outside
the scope of this document. In particular, lawful intercept is
outside the scope of this document.
Furthermore, the scale and cost burdens vary widely, in all markets,
where the different needs for solution capabilities such as media
injection, transcoding, and security-related needs do not conform
well to a one-size-fits-all model. If a standardized solution
supports all of the requirements from every recording market, but
doing so would be expensive for markets with lesser needs, then
proprietary solutions for those markets will continue to propagate.
Care must be taken, therefore, to make a standards-based solution
support optionality and flexibility.
This document specifies requirements for using SIP [RFC3261] between
a Session Recording Client and a Session Recording Server to control
the recording of media that has been transmitted in the context of a
Communication Session. A Communication Session is the "call" between
participants. The Session Recording Client is the source of the
recorded media. The Session Recording Server is the sink of recorded
media. It should be noted that the requirements for the protocol
between a Session Recording Server and Session Recording Client have
very similar requirements (such as codec and transport negotiation,
encryption key interchange, firewall traversal) as compared to
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regular SIP media sessions. The choice of SIP for session recording
provides reuse of an existing protocol.
The recorded sessions can be any RTP media sessions including voice,
DTMF (as defined by [RFC4733]), video, and text (as defined by
[RFC4103]).
An archived session recording is typically comprised of the
Communication Session media content and the Communication Session
Metadata. The Communication Session Metadata allows recording
archives to be searched and filtered at a later time and allows a
session to be played back in a meaningful way, e.g., with correct
synchronization between the media. The Communication Session
Metadata needs to be conveyed from the Session Recording Client to
the Session Recording Server.
This document only considers active recording, where the Session
Recording Client purposefully streams media to a Session Recording
Server. Passive recording, where a recording device detects media
directly from the network, is outside the scope of this document.
2. Requirements notation
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119] and indicate
requirement levels for compliant mechanisms.
3. Definitions
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 typically
implemented as a multi-port device that is capable of receiving media
from multiple sources simultaneously. An SRS is 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 provides
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metadata to the SRS.
Communication Session (CS): A session created between two or more SIP
User Agents (UAs) that is the subject of 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
Metadata: Information that describes recorded media and the CS to
which they relate.
Pause and Resume during a Communication Session: Pause: The action of
temporarily discontinuing the transmission and collection of RS media
Resume: The action of recommencing the transmission and collection of
RS media
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4. Use Cases
Use Case 1: Full-time Recording: One Recording Session for each
Communication Session.
For example, the diagram below shows the lifecycle of Communication
Sessions (CS) and the relationship to the Recording Sessions (RS)
CS |--- CS 1 ---| |--- CS 2 ---| |--- CS 3 ---|
RS |--- RS 1 ---| |--- RS 2 ---| |--- RS 3 ---|
Figure 2
Record every CS for specific extension/person.
The need to record all calls is typically due to business process
purposes (such as transaction confirmation or dispute resolution) or
to ensure compliance with governmental regulations. Applications
include enterprise, contact center, and financial trading floors.
Also commonly known as Total Recording.
Use Case 2: Selective Recording: Start a Recording Session when a
Communication Session to be recorded is established.
In this example, Communication Sessions 1 and 3 are recorded but CS 2
is not.
CS |--- CS 1 ---| |--- CS 2 ---| |--- CS 3 ---|
RS |--- RS 1----| |--- RS 2 ---|
Figure 3
Use Case 3: Start/Stop a Recording Session during a Communication
Session.
The Recording Session starts during a Communication Session, either
manually via a user-controlled mechanism (e.g. button on user's
phone) or automatically via an application (e.g. a Contact Center
customer service application) or business event. A Recording Session
either ends during the Communication Session, or when the
Communication Session ends. One or more Recording Sessions may
record each Communication Session.
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CS |------------- Communication Session -----------|
RS |---- RS 1 ----| |---- RS 2 -----|
Figure 4
Use Case 4: Persistent Recording: A single Recording Session captures
one or more Communication Sessions.
|--- CS 1 ---| |--- CS 2 ---| |--- CS 3 ---|
RS |---------------------- Recording Session ---------------------|
Figure 5
A Recording Session records continuously without interruption.
Periods when there is no CS in progress must be reproduced upon
playback (e.g. by recording silence during such periods or by not
recording such periods but marking them by means of metadata for
utilization on playback, etc.). Applications include financial
trading desks and emergency (first-responder) service bureaus. The
length of a Persistent Recording Session is independent from the
length of the actual Communication Sessions. Persistent Recording
Sessions avoid issues such as media clipping that can occur due to
delays in Recording Session establishment.
The connection and attributes of media in the Recording Session are
not dynamically signaled for each Communication Session before it can
be recorded; however, codec re-negotiation is possible.
In some cases, more than one concurrent Communication Session (on a
single end-user apparatus, e.g. trading floor turret) is mixed into
one Recording Session:
|-------- CS 1 -------|
|-------- CS 2 -------|
|-------- CS 3 -------|
RS |----------- Recording Session --------------|
Figure 6
Use Case 5: Real-time Recording Controls.
For an active Recording Session, privacy or security reasons may
demand not capturing a specific portion of a conversation. An
example is for PCI (payment card industry) compliance where credit
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card info must be protected. One solution is to not record a caller
speaking their credit card information.
An example of a real-time controls is Pause/Resume.
Use Case 6: IVR / Voice Portal Recording.
Self-service Interactive Voice Response applications may need to be
recorded for application performance tuning or to meet compliance
requirements.
Metadata about an IVR session recording must include session
information and may include application context information (e.g.
VoiceXML session variables, dialog names, etc.)
Use Case 7: Enterprise Mobility Recording.
Many agents and enterprise workers whose calls are to be recorded are
not located on company premises.
Examples:
o Home-based agents or enterprise workers.
o Mobile phones of knowledge workers when they conduct work related
(and legally required recording) calls. e.g. insurance agents,
brokers, physicians.
Use Case 8: Geographically distributed or centralized recording.
Enterprises such as banks, insurance agencies, and retail stores may
have many locations, possibly up to thousands of small sites.
Frequently only phones and network infrastructure are installed in
branches, without local recording services. In cases where calls
inside or between branches must be recorded, a centralized recording
system in data centers together with telephony infrastructure (e.g.
PBX) may be deployed.
Use Case 9: Record complex call scenarios.
The following is an example of a scenario where one call that is
recorded must be associated with a related call that also must be
recorded.
o A Customer is in a conversation with a Customer Service Agent.
o Agent puts Customer on hold in order to consult with a Supervisor.
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o Agent enters into a conversation with Supervisor.
o Agent disconnects from Supervisor, then reconnects with Customer.
o The Supervisor call must be associated with the original customer
call.
Use case 10: High availability and continuous recording.
Specific deployment scenarios present different requirements for
system availability, error handling, etc. including:
o An SRS must always be available at call setup time.
o No loss of media recording, including during failure of an SRS.
o The Communication Session must be terminated (or suitable
notification given to parties) in the event of a recording failure.
Use Case 11: Record multi-channel, multi-media session.
Some applications require the recording of more than one media
stream, possibly of different types. Media are synchronized, either
at storage or at playback.
Speech analytics technologies (e.g. word spotting, emotion detection,
speaker identification) may require speaker-separated recordings for
optimum performance.
Multi-modal Contact Centers may include audio, video, IM or other
interaction modalities.
In trading floors environments, in order to minimize storage and
recording system resources, it may be preferable to mix multiple
concurrent calls (Communication Sessions) on different handsets/
speakers on the same turret into single recording session.
Use Case 12: Real-time media processing.
It must be possible for an SRS to support real-time media processing,
such as speech analytics of trading floor interactions. Real-time
analytics may be employed for automatic intervention (stopping
interaction or alerting) if for example, a trader is not following
regulations.
Speaker separation is required in order to reliably detect who is
saying specific phrases.
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5. Requirements
The following are requirements for SIP-based Media Recording:
o REQ-001 The mechanism MUST provide a means for using the SIP
protocol for establishing, maintaining and terminating Recording
Sessions between a Session Recording Client and a Session Recording
Server.
o REQ-002 The mechanism MUST support the ability to record all CSs in
their entirety.
o REQ-003 The mechanism MUST support the ability to record selected
CSs in their entirety, according to policy.
o REQ-004 The mechanism MUST support the ability to record selected
parts of selected CSs.
o REQ-005 The mechanism MUST support the ability to record a CS
without loss of media (for example, clipping media at the beginning
of the CS) due to RS recording preparation and also, without
impacting the quality or timing of the CS (for example, delaying the
start of the CS while preparation for recording session). See Use
Case 4 in Section 4 for more details.
o REQ-006 The mechanism MUST support the recording of IVR sessions.
o REQ-007 The mechanism MUST support the recording of RTP media types
voice, DTMF (as defined by [RFC4733]), video, and text (as defined by
[RFC4103]).
o REQ-008 The mechanism MUST support the ability for an SRC to
deliver mixed audio streams from multiple Communication Sessions to
an SRS.
Note: A mixed audio stream is where several related Communication
Sessions are carried in a single Recording Session. A mixed media
stream is typically produced by a mixer function. The RS MAY be
informed about the composition of the mixed streams through session
metadata.
o REQ-009: The mechanism MUST support the ability for an SRC to
deliver mixed audio streams from different parties of a given
Communication Session to an SRS.
o REQ-010 The mechanism MUST support the ability to deliver to the
SRS multiple media streams for a given CS.
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o REQ-011 The mechanism MUST support the ability to pause and resume
the transmission and collection of RS media.
o REQ-012 The mechanism MUST include a means for providing the SRS
with metadata describing CSs that are being recorded, including the
media being used and the identities of parties involved.
o REQ-013 The mechanism MUST include a means for the SRS to be able
to correlate RS media with CS participant media.
o REQ-014 Metadata format must be agnostic of the transport protocol.
o REQ-015: The mechanism MUST support a means to stop the recording.
o REQ-016: The mechanism MUST support a means for a recording-aware
UA involved in a CS to request at session establishment time that the
CS should be recorded or should not be recorded, the honoring of such
a request being dependent on policy.
o REQ-017: The mechanism MUST support a means for a recording-aware
UA involved in a CS to request during a session that the recording of
the CS should be started, paused, resumed or stopped, the honoring of
such a request being dependent on policy.
o REQ-018 The mechanism MUST NOT prevent the application of tones or
announcements during recording or at the start of a CS to support
notification to participants that the call is being recorded or may
be recorded.
o REQ-019 The mechanism MUST provide a means of indicating to
recording-aware UAs whether recording is taking place, for
appropriate rendering at the user interface.
o REQ-020 The mechanism MUST provide a way for metadata to be
conveyed to the SRS incrementally during the CS.
o REQ-021 The mechanism MUST NOT prevent high availability
deployments.
o REQ-022 The mechanism MUST provide means for facilitating
synchronization of the recorded media streams and metadata.
o REQ-023 The mechanism MUST provide means for facilitating
synchronization among the recorded media streams.
o REQ-024 The mechanism MUST provide means to relate recording and
recording controls such as start/stop/pause/resume to the wall clock
time.
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o REQ-025 The mechanism MUST support functionality such that if the
CS is encrypted, the RS may use the same or different encryption
keys.
o REQ-026 The mechanism MUST provide means for an SRS to authenticate
the SRC on RS initiation.
o REQ-027 The mechanism MUST provide means for an SRC to authenticate
the SRS on RS initiation.
o REQ-028 The mechanism MUST include a means for ensuring that the
integrity of the metadata sent from SRC to SRS is an accurate
representation of the original CS metadata.
o REQ-029 The mechanism MUST include a means for ensuring that the
integrity of the media sent from SRC to SRS is an accurate
representation of the original CS media.
o REQ-030 The mechanism MUST include a means for ensuring the
confidentiality of the Metadata sent from SRC to SRS.
o REQ-031 The mechanism MUST provide a means to support RS
confidentiality.
o REQ-032 The mechanism MUST support the ability to deliver to the
SRS multiple media streams of the same media type (e.g. audio,
video). For example in the case of delivering unmixed audio for each
participant in the CS.
6. Privacy Considerations
Respecting the privacy rights and wishes of users engaged in a call
is of paramount importance. In many jurisdictions participants have
a right to know that the session is being recorded or might be
recorded, and have a right to opt out, either by terminating the call
or by demanding that the call not be recorded. Therefore this
document contains requirements for being able to notify users that a
call is being recorded and for users to be able to request that a
call not be recorded. Use cases where users participating in a call
are not informed that the call is or might be recorded are outside
the scope of this document. In particular, lawful intercept is
outside the scope of this document.
Requirements for participant notification of recording vary widely by
jurisdiction. In a given deployment, not all users will be
authorized to stop the recording of a CS (although any user can
terminate its participation in a CS). Typically users within the
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domain that is carrying out the recording will be subject to policies
of that domain concerning whether CSs are recorded. For example, in
a call centre, agents will be subject to policies of the call centre
and may or may not have the right to prevent the recording of a CS or
part of a CS. Users calling into the call centre, on the other hand,
will typically have to ask the agent not to record the CS. If the
agent is unable to prevent recording, or if the caller does not trust
the agent, the only option generally is to terminate the CS.
Privacy considerations also extend to what happens to a recording
once it has been created. Typical issues are who can access the
recording (e.g., receive a copy of the recording, view the metadata,
play back the media, etc.), for what purpose the recording can be
used (e.g., for non-repudiation, for training purposes, for quality
control purposes, etc.) and for how long the recording is to be
retained before deletion. These are typically policies of the domain
that makes the recording, rather than policies of individual users
involved in a recorded CS, whether those users be in the same domain
or in a different domain. Taking the call centre example again,
agents might be made aware of call centre policy regarding retention
and use of recordings as part of their employment contract, and
callers from outside the call centre might be given some information
about policy when notified that a CS will be recorded (e.g., through
an announcement that says that calls may be recorded for quality
purposes).
This document does not specify any requirements for a user engaged in
a CS to be able to dictate policy for what happens to a recording, or
for such information to be conveyed from an SRC to an SRS. It is
assumed that the SRS has access to policy applicable to its
environment and can ensure that recordings are stored and used in
accordance with that policy.
7. Security Considerations
Session recording has substantial security implications, for the SIP
UA's being recorded, the SRC, and the SRS.
For the SIP UA's involved in the Communication Session, the
requirements in this draft enable the UA to identify that a
Communication Session is being recorded and for the UA to request
that a given Communication Session is not subject to recording.
Since humans don't typically look at or know about protocol signaling
such as SIP, and indeed the SIP session might have originated through
a PSTN Gateway without any ability to pass on in-signaling
indications of recording, users can be notified of recording in the
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media itself through voice announcements, a visual indicator on the
endpoint, or other means.
With regards to security implications of the protocol(s), clearly
there is a need for authentication, authorization, eavesdropping
protection, and non-repudiation for the solution. The SRC needs to
know the SRS it is communicating with is legitimate, and vice-versa,
even if they are in different domains. Both the signaling and media
for the Recording Session need the ability to be authenticated and
protected from eavesdropping and non-repudiation. Requirements are
detailed in the requirements section.
Communication Sessions and Recording Sessions can require different
security levels both for signaling and media, depending on deployment
configurations. For some environments, for example, SRS and SRC will
be collocated in a secure network region and therefore the RS will
not require the same protection level as a CS that extends over a
public network, for example. For other environments, the SRS can be
located in a public cloud, for example, and the RS will require a
higher protection level than the CS. For these reasons, there is not
a direct relationship between the security level of Communication
Sessions and the security level of Recording Sessions.
A malicious or corrupt SRC can tamper with media and metadata
relating to a CS before sending to an SRS. Also CS media and
signaling can be tampered with in the network prior to reaching an
SRC, unless proper means are provided to ensure integrity protection
during transmission on the CS. Means for ensuring the integrity and
correctness of media and metadata emitted by an SRC are outside the
scope of this work. Other organizational and technical controls will
need to be used to prevent tampering.
8. IANA Considerations
This document has no IANA actions.
9. Acknowledgements
Thanks to Dan Wing, Alan Johnson, Vijay Gurbani, Cullen Jennings,
Hadriel Kaplan, Henry Lum, Dave Smith, Martin Palmer, Alissa Cooper,
Deepanshu Gautam, Paul Kyzivat, Parthasarathi R, Ram Mohan R, and
Charles Eckel for their significant contributions and assistance with
this document and Working Group, and to all the members of the
DISPATCH WG and SIPREC WG mailing lists for providing valuable input
to this work.
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10. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
A., Peterson, J., Sparks, R., Handley, M., and E.
Schooler, "SIP: Session Initiation Protocol", RFC 3261,
June 2002.
[RFC4103] Hellstrom, G. and P. Jones, "RTP Payload for Text
Conversation", RFC 4103, June 2005.
[RFC4733] Schulzrinne, H. and T. Taylor, "RTP Payload for DTMF
Digits, Telephony Tones, and Telephony Signals", RFC 4733,
December 2006.
Authors' Addresses
Ken Rehor (editor)
Cisco Systems
170 West Tasman Dr.
Mail Stop SJC30/2/
San Jose, CA 95134
USA
Email: krehor@cisco.com
Leon Portman (editor)
NICE Systems
8 Hapnina
Ra'anana 43017
Israel
Email: leon.portman@nice.com
Andrew Hutton
Siemens Enterprise Communications
Email: andrew.hutton@siemens-enterprise.com
URI: http://www.siemens-enterprise.com
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Rajnish Jain
IPC Systems
777 Commerce Drive
Fairfield, CT 06825
USA
Email: rajnish.jain@ipc.com
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