draft-ietf-sip-hitchhikers-guide-01.txt   draft-ietf-sip-hitchhikers-guide-02.txt 
SIP J. Rosenberg SIP J. Rosenberg
Internet-Draft Cisco Systems Internet-Draft Cisco
Expires: April 20, 2007 October 17, 2006 Intended status: Informational March 5, 2007
Expires: September 6, 2007
A Hitchhikers Guide to the Session Initiation Protocol (SIP) A Hitchhiker's Guide to the Session Initiation Protocol (SIP)
draft-ietf-sip-hitchhikers-guide-01 draft-ietf-sip-hitchhikers-guide-02
Status of this Memo Status of this Memo
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Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2006). Copyright (C) The IETF Trust (2007).
Abstract Abstract
The Session Initiation Protocol (SIP) is the subject of numerous The Session Initiation Protocol (SIP) is the subject of numerous
specifications that have been produced by the IETF. It can be specifications that have been produced by the IETF. It can be
difficult to locate the right document, or even to determine the set difficult to locate the right document, or even to determine the set
of Request for Comments (RFC) about SIP. Don't Panic! This of Request for Comments (RFC) about SIP. This specification serves
specification serves as a guide to the SIP RFC series. It lists the as a guide to the SIP RFC series. It lists the specifications under
specifications under the SIP umbrella, briefly summarizes each, and the SIP umbrella, briefly summarizes each, and groups them into
groups them into categories. categories.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Scope of this Document . . . . . . . . . . . . . . . . . . . . 3 2. Scope of this Document . . . . . . . . . . . . . . . . . . . . 3
3. Core SIP Specifications . . . . . . . . . . . . . . . . . . . 4 3. Core SIP Specifications . . . . . . . . . . . . . . . . . . . 4
4. Public Switched Telephone Network (PSTN) Interworking . . . . 7 4. Public Switched Telephone Network (PSTN) Interworking . . . . 7
5. General Purpose Infrastructure Extensions . . . . . . . . . . 8 5. General Purpose Infrastructure Extensions . . . . . . . . . . 8
6. Minor Extensions . . . . . . . . . . . . . . . . . . . . . . . 10 6. NAT Traversal . . . . . . . . . . . . . . . . . . . . . . . . 11
7. Conferencing . . . . . . . . . . . . . . . . . . . . . . . . . 12 7. Minor Extensions . . . . . . . . . . . . . . . . . . . . . . . 12
8. Call Control Primitives . . . . . . . . . . . . . . . . . . . 12 8. Conferencing . . . . . . . . . . . . . . . . . . . . . . . . . 13
9. Event Framework and Packages . . . . . . . . . . . . . . . . . 13 9. Call Control Primitives . . . . . . . . . . . . . . . . . . . 14
10. Quality of Service . . . . . . . . . . . . . . . . . . . . . . 15 10. Event Framework and Packages . . . . . . . . . . . . . . . . . 14
11. Operations and Management . . . . . . . . . . . . . . . . . . 15 11. Quality of Service . . . . . . . . . . . . . . . . . . . . . . 16
12. SIP Compression . . . . . . . . . . . . . . . . . . . . . . . 16 12. Operations and Management . . . . . . . . . . . . . . . . . . 17
13. SIP Service URIs . . . . . . . . . . . . . . . . . . . . . . . 16 13. SIP Compression . . . . . . . . . . . . . . . . . . . . . . . 17
14. Security Mechanisms . . . . . . . . . . . . . . . . . . . . . 17 14. SIP Service URIs . . . . . . . . . . . . . . . . . . . . . . . 17
15. Instant Messaging and Presence . . . . . . . . . . . . . . . . 19 15. Security Mechanisms . . . . . . . . . . . . . . . . . . . . . 18
16. Emergency Services . . . . . . . . . . . . . . . . . . . . . . 19 16. Instant Messaging, Presence and Multimedia . . . . . . . . . . 20
17. Security Considerations . . . . . . . . . . . . . . . . . . . 19 17. Emergency Services . . . . . . . . . . . . . . . . . . . . . . 20
18. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19 18. Security Considerations . . . . . . . . . . . . . . . . . . . 21
19. Informative References . . . . . . . . . . . . . . . . . . . . 20 19. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 29 20. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 21
Intellectual Property and Copyright Statements . . . . . . . . . . 30 21. Informative References . . . . . . . . . . . . . . . . . . . . 21
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 30
Intellectual Property and Copyright Statements . . . . . . . . . . 31
1. Introduction 1. Introduction
The Session Initiation Protocol (SIP) [1] is the subject of numerous The Session Initiation Protocol (SIP) [1] is the subject of numerous
specifications that have been produced by the IETF. It can be specifications that have been produced by the IETF. It can be
difficult to locate the right document, or even to determine the set difficult to locate the right document, or even to determine the set
of Request for Comments (RFC) about SIP. Don't Panic! [42] This of Request for Comments (RFC) about SIP. Don't Panic! [42] This
specification serves as a guide to the SIP RFC series. It lists the specification serves as a guide to the SIP RFC series. It lists the
specifications under the SIP umbrella. For each specification, a specifications under the SIP umbrella. For each specification, a
paragraph or so description is included that summarizes the purpose paragraph or so description is included that summarizes the purpose
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I: Informational I: Informational
The specifications are grouped together by topic. Typically, SIP The specifications are grouped together by topic. Typically, SIP
extensions fit naturally into topic areas, and implementations extensions fit naturally into topic areas, and implementations
interested in a particular topic often implement many or all of the interested in a particular topic often implement many or all of the
specifications in that area. There are some specifications which specifications in that area. There are some specifications which
fall into multiple topic areas, in which case they are listed more fall into multiple topic areas, in which case they are listed more
than once. than once.
This document itself is not an update to RFC 3261 or an extension to This document itself is not an update to RFC 3261 or an extension to
SIP. It is an informational document, meant to guide newcomers and SIP. It is an informational document, meant to guide newcomers,
implementors to the SIP suite of specifications. implementors and deployers to the SIP suite of specifications.
2. Scope of this Document 2. Scope of this Document
It is very difficult to enumerate the set of SIP specifications. It is very difficult to enumerate the set of SIP specifications.
This is because there are many protocols that are intimately related This is because there are many protocols that are intimately related
to SIP and used by nearly all SIP implementations, but are not to SIP and used by nearly all SIP implementations, but are not
formally SIP extensions. As such, this document formally defines a formally SIP extensions. As such, this document formally defines a
"SIP specification" as: "SIP specification" as:
o Any specification that defines an extension to SIP itself, where o Any specification that defines an extension to SIP itself, where
an extension is a mechanism that changes or updates in some way a an extension is a mechanism that changes or updates in some way a
behavior specified in RFC 3261 behavior specified in RFC 3261
o Any specification that defines an extension to SDP whose primary o Any specification that defines an extension to SDP whose primary
purpose is to support SIP purpose is to support SIP
o Any specification that defines a MIME object whose primary purpose o Any specification that defines a MIME object whose primary purpose
is to support SIP is to support SIP
Excluded from this list are requirements, architectures, registry Excluded from this list are requirements, architectures, registry
definitions, non-normative frameworks, and processes. Best Current definitions, non-normative frameworks, and processes. Best Current
Practices are included when they are effectively standard mechanisms Practices are included when they normatively define mechanisms for
for accomplishing a task. accomplishing a task.
The SIP change process [8] defines two types of extensions to SIP. The SIP change process [8] defines two types of extensions to SIP.
These are normal extensions and the so-called P-headers, which are These are normal extensions and the so-called P-headers (where P
meant to be used in areas of limited applicability. P-headers cannot stands for "preliminary", "private", or "proprietary", and the "P-"
be defined in the standards track. For the most part, P-headers are prefix is included in the header field name) are meant to be used in
not included in the listing here, with the exception of those which areas of limited applicability. P-headers cannot be defined in the
have seen general usage despite their P-header status. standards track. For the most part, P-headers are not included in
the listing here, with the exception of those which have seen general
usage despite their P-header status.
3. Core SIP Specifications 3. Core SIP Specifications
The core SIP specifications represent the set of specifications whose The core SIP specifications represent the set of specifications whose
functionality is broadly applicable. An extension is broadly functionality is broadly applicable. An extension is broadly
applicable if it fits into one of the following categories: applicable if it fits into one of the following categories:
o For specifications that impact SIP session management, the o For specifications that impact SIP session management, the
extension would be used for almost every session initiated by a extension would be used for almost every session initiated by a
user agent user agent
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P-Asserted-ID header field has been widely deployed. It is used P-Asserted-ID header field has been widely deployed. It is used
as the basic mechanism for providing secure caller ID services. as the basic mechanism for providing secure caller ID services.
RFC 3327, SIP Extension Header Field for Registering Non-Adjacent RFC 3327, SIP Extension Header Field for Registering Non-Adjacent
Contacts (S): RFC 3327 [16] defines the Path header field. This Contacts (S): RFC 3327 [16] defines the Path header field. This
field is inserted by proxies between a client and their registrar. field is inserted by proxies between a client and their registrar.
It allows inbound requests towards that client to traverse these It allows inbound requests towards that client to traverse these
proxies prior to being delivered to the user agent. It is proxies prior to being delivered to the user agent. It is
essential in any SIP deployment that has edge proxies, which are essential in any SIP deployment that has edge proxies, which are
proxies between the client and the home proxy or SIP registrar. proxies between the client and the home proxy or SIP registrar.
It is also instrumental in the SIP NAT traversal specifications.
RFC 3581, An Extension to SIP for Symmetric Response Routing (S): RFC RFC 3581, An Extension to SIP for Symmetric Response Routing (S):
3581 [17] defines the rport parameter of the Via header. It is an RFC 3581 [17] defines the rport parameter of the Via header. It
essential piece of getting SIP through NAT. NAT traversal for SIP is an essential piece of getting SIP through NAT. NAT traversal
is considered a core part of the specifications. for SIP is considered a core part of the specifications.
RFC 3840, Indicating User Agent Capabilities in SIP (S): RFC 3840 RFC 3840, Indicating User Agent Capabilities in SIP (S): RFC 3840
[33] defines a mechanism for carrying capability information about [33] defines a mechanism for carrying capability information about
a user agent in REGISTER requests and in dialog-forming requests a user agent in REGISTER requests and in dialog-forming requests
like INVITE. It has found use with conferencing (the isfocus like INVITE. It has found use with conferencing (the isfocus
parameter declares that a user agent is a conference server) and parameter declares that a user agent is a conference server) and
with applications like push-to-talk. with applications like push-to-talk.
RFC 4320, Actions Addressing Issues Identified with the Non-INVITE RFC 4320, Actions Addressing Issues Identified with the Non-INVITE
Transaction in SIP (S): RFC 4320 [18] formally updates RFC 3261, and Transaction in SIP (S): RFC 4320 [18] formally updates RFC 3261, and
modifies some of the behaviors associated with non-INVITE modifies some of the behaviors associated with non-INVITE
transactions. These address some problems found in timeout and transactions. These address some problems found in timeout and
failure cases. failure cases.
RFC 4474, Enhancements for Authenticated Identity Management in SIP RFC 4474, Enhancements for Authenticated Identity Management in SIP
(S): RFC 4474 [19] defines a mechanism for providing a (S): RFC 4474 [19] defines a mechanism for providing a
cryptographically verifiable identity of the calling party in a cryptographically verifiable identity of the calling party in a
SIP request. Also known as "SIP Identity", this mechanism SIP request. Known as "SIP Identity", this mechanism provides an
provides an alternative to RFC 3325. It has seen little alternative to RFC 3325. It has seen little deployment so far,
deployment so far, but its importance as a key construct for but its importance as a key construct for anti-spam techniques
almost also anti-spam techniques makes it a core part of the SIP makes it a core part of the SIP specifications.
specifications.
RFC XXXX, Obtaining and Using Globally Routable User Agent RFC XXXX, Obtaining and Using Globally Routable User Agent
Identifiers (GRUU) in SIP (S): RFC XXXX [20] defines a mechanism for Identifiers (GRUU) in SIP (S): RFC XXXX [20] defines a mechanism for
directing requests towards a specific UA instance. GRUU is directing requests towards a specific UA instance. GRUU is
essential for features like transfer and provides another piece of essential for features like transfer and provides another piece of
the SIP NAT traversal story. the SIP NAT traversal story.
RFC XXXX, Managing Client Initiated Connections through SIP (S): RFC RFC XXXX, Managing Client Initiated Connections through SIP (S): RFC
XXXX [21], also known as SIP outbound, defines important changes XXXX [21], also known as SIP outbound, defines important changes
to the SIP registration mechanism which enable delivery of SIP to the SIP registration mechanism which enable delivery of SIP
messages towards a UA when it is behind a NAT. This specification messages towards a UA when it is behind a NAT. This specification
is the cornerstone of the SIP NAT traversal strategy. is the cornerstone of the SIP NAT traversal strategy.
RFC 4566, Session Description Protocol (S): RFC 4566 [78] defines a RFC 4566, Session Description Protocol (S): RFC 4566 [78] defines a
format for representing multimedia sessions. SDP objects are format for representing multimedia sessions. SDP objects are
carried in the body of SIP messages, and based on the offer/answer carried in the body of SIP messages, and based on the offer/answer
model, are used to negotiate the media characteristics of a model, are used to negotiate the media characteristics of a
session between users. session between users.
RFC XXXX, SDP Capability Negotiation (S): RFC XXXX [105] defines a
set of extensions to SDP that allow for capability negotiation
within SDP. Capability negotiation can be used to select between
different profiles of RTP (secure vs. unsecure) or to negotiate
codecs such that an agent has to select one amongst a set of
supported codecs.
RFC 3388, Grouping of Media Lines in the Session Description Protocol RFC 3388, Grouping of Media Lines in the Session Description Protocol
(S): RFC 3388 [79] defines a framework for grouping together media (S): RFC 3388 [79] defines a framework for grouping together media
streams in an SDP message. Such a grouping allows relationships streams in an SDP message. Such a grouping allows relationships
between these streams, such as which stream is the audio for a between these streams, such as which stream is the audio for a
particular video feed, to be expressed. particular video feed, to be expressed.
RFC XXXX, Interactive Connectivity Establishment (ICE) (S): RFC XXXX RFC XXXX, Interactive Connectivity Establishment (ICE) (S): RFC XXXX
[5] defines a technique for NAT traversal of media sessions for [5] defines a technique for NAT traversal of media sessions for
protocols that make use of the offer/answer model. This protocols that make use of the offer/answer model. This
specification is the IETF recommended mechanism for NAT traversal specification is the IETF recommended mechanism for NAT traversal
for SIP media streams, and is meant to be used even by endpoints for SIP media streams, and is meant to be used even by endpoints
which are themselves never behind a NAT. which are themselves never behind a NAT. A SIP option tag and
media feature tag RFC XXXX [108] have been defined for use with
ICE.
RFC 3605, Real Time Control Protocol (RTCP) Attribute in the Session RFC 3605, Real Time Control Protocol (RTCP) Attribute in the Session
Description Protocol (SDP) (S): RFC 3605 [80] defines a way to Description Protocol (SDP) (S): RFC 3605 [80] defines a way to
explicitly signal, within an SDP message, the IP address and port explicitly signal, within an SDP message, the IP address and port
for RTCP, rather than using the port+1 rule in the Real Time for RTCP, rather than using the port+1 rule in the Real Time
Transport Protocol (RTP) [3]. It is needed for devices behind NAT Transport Protocol (RTP) [3]. It is needed for devices behind NAT
and used by ICE. and used by ICE.
RFC XXXX, Connected Identity in the Session Initiation Protocol (SIP) RFC XXXX, Connected Identity in the Session Initiation Protocol (SIP)
(S): RFC XXXX [81] defines an extension to SIP that allows a UAC to (S): RFC XXXX [81] defines an extension to SIP that allows a UAC to
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relatively narrow focus and has not seen widespread deployment. relatively narrow focus and has not seen widespread deployment.
RFC 3910, The SPIRITS Protocol (S): Continuing the trend of naming RFC 3910, The SPIRITS Protocol (S): Continuing the trend of naming
PSTN related extensions with alcohol references, SPIRITS [23] PSTN related extensions with alcohol references, SPIRITS [23]
defines the inverse of PINT. It allows a switch in the PSTN to defines the inverse of PINT. It allows a switch in the PSTN to
ask an IP element about how to proceed with call waiting. It was ask an IP element about how to proceed with call waiting. It was
developed primarily to support Internet Call Waiting (ICW). developed primarily to support Internet Call Waiting (ICW).
Perhaps the next specification will be called the Pan Galactic Perhaps the next specification will be called the Pan Galactic
Gargle Blaster [42]. Gargle Blaster [42].
RFC 3372, SIP for Telephones (SIP-T): Context and Architectures RFC 3372, SIP for Telephones (SIP-T): Context and Architectures (I):
(I): SIP-T [24] defines a mechanism for using SIP between pairs of SIP-T [24] defines a mechanism for using SIP between pairs of PSTN
PSTN gateways. Its essential idea is to tunnel ISUP signaling gateways. Its essential idea is to tunnel ISUP signaling between
between the gateways in the body of SIP messages. SIP-T motivated the gateways in the body of SIP messages. SIP-T motivated the
the development of INFO [30]. SIP-T has seen widespread development of INFO [30]. SIP-T has seen widespread
implementation. implementation.
RFC 3398, ISUP to SIP Mapping (S): RFC 3398 [25] defines how to do RFC 3398, ISUP to SIP Mapping (S): RFC 3398 [25] defines how to do
protocol mapping from the SS7 ISDN User Part (ISUP) signaling to protocol mapping from the SS7 ISDN User Part (ISUP) signaling to
SIP. It is widely used in SS7 to SIP gateways and is part of the SIP. It is widely used in SS7 to SIP gateways and is part of the
SIP-T framework. SIP-T framework.
RFC 3578, Mapping of ISUP Overlap Signaling to SIP (S): RFC 3578 [26] RFC 3578, Mapping of ISUP Overlap Signaling to SIP (S): RFC 3578
defines a mechanism to map overlap dialing into SIP. This [26] defines a mechanism to map overlap dialing into SIP. This
specification is widely regarded as the ugliest SIP specification, specification is widely regarded as the ugliest SIP specification,
as the introduction to the specification itself advises that it as the introduction to the specification itself advises that it
has many problems. Overlap signaling (the practice of sending has many problems. Overlap signaling (the practice of sending
digits into the network as dialed instead of waiting for complete digits into the network as dialed instead of waiting for complete
collection of the called party number) is largely incompatible collection of the called party number) is largely incompatible
with SIP at some fairly fundamental levels. That said, RFC 3578 with SIP at some fairly fundamental levels. That said, RFC 3578
is mostly harmless and has seen some usage. is mostly harmless and has seen some usage.
RFC 3960, Early Media and Ringtone Generation in SIP (I): RFC 3960 RFC 3960, Early Media and Ringtone Generation in SIP (I): RFC 3960
[27] defines some guidelines for handling early media - the [27] defines some guidelines for handling early media - the
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PRACK brings a great deal of complication for relatively small PRACK brings a great deal of complication for relatively small
benefit. As such, it has seen only mild levels of deployment. benefit. As such, it has seen only mild levels of deployment.
RFC 3323, A Privacy Mechanism for the Session Initiation Protocol RFC 3323, A Privacy Mechanism for the Session Initiation Protocol
(SIP) (S): RFC 3323 [14] defines the Privacy header field, used by (SIP) (S): RFC 3323 [14] defines the Privacy header field, used by
clients to request anonymity for their requests. Though it clients to request anonymity for their requests. Though it
defines numerous privacy services, the only one broadly used is defines numerous privacy services, the only one broadly used is
the one that supports privacy of the P-Asserted-ID header field the one that supports privacy of the P-Asserted-ID header field
[15]. [15].
RFC 3311, The SIP UPDATE Method (S): RFC 3311 [29] defines the UPDATE RFC 3311, The SIP UPDATE Method (S): RFC 3311 [29] defines the
method for SIP. This method is meant as a means for updating UPDATE method for SIP. This method is meant as a means for
session information prior to the completion of the initial INVITE updating session information prior to the completion of the
transaction. It was developed primarily to support RFC 3312 [59]. initial INVITE transaction. It was developed primarily to support
RFC 3312 [59].
RFC 2976, The INFO Method (S): RFC 2976 [30] was defined as an RFC 2976, The INFO Method (S): RFC 2976 [30] was defined as an
extension to RFC 2543. It defines a method, INFO, used to extension to RFC 2543. It defines a method, INFO, used to
transport mid-dialog information that has no impact on SIP itself. transport mid-dialog information that has no impact on SIP itself.
Its driving application was the transport of PSTN related Its driving application was the transport of PSTN related
information when using SIP between a pair of gateways. Though information when using SIP between a pair of gateways. Though
originally conceived for broader use, it only found standardized originally conceived for broader use, it only found standardized
usage with SIP-T [24]. It has been used to support numerous usage with SIP-T [24]. It has been used to support numerous
proprietary and non-interoperable extensions due to its poorly proprietary and non-interoperable extensions due to its poorly
defined scope. defined scope.
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For example, it is used to report back on the responses received For example, it is used to report back on the responses received
to a request sent as a consequence of a REFER. to a request sent as a consequence of a REFER.
RFC 3608, SIP Extension Header Field for Service Route Discovery RFC 3608, SIP Extension Header Field for Service Route Discovery
During Registration (S): RFC 3608 [32] allows a client to determine, During Registration (S): RFC 3608 [32] allows a client to determine,
from a REGISTER response, a path of proxies to use in requests it from a REGISTER response, a path of proxies to use in requests it
sends outside of a dialog. In many respects, it is the inverse of sends outside of a dialog. In many respects, it is the inverse of
the Path header field, but has seen less usage since default the Path header field, but has seen less usage since default
outbound proxies have been sufficient in many deployments. outbound proxies have been sufficient in many deployments.
RFC 3841, Caller Preferences for SIP (S): RFC 3841 [34] defines a set RFC 3841, Caller Preferences for SIP (S): RFC 3841 [34] defines a
of headers that a client can include in a request to control the set of headers that a client can include in a request to control
way in which the request is routed downstream. It allows a client the way in which the request is routed downstream. It allows a
to direct a request towards a UA with specific capabilities. client to direct a request towards a UA with specific
capabilities.
RFC 4028, Session Timers in SIP (S): RFC 4028 [35] defines a RFC 4028, Session Timers in SIP (S): RFC 4028 [35] defines a
keepalive mechanism for SIP signaling. It is primarily meant to keepalive mechanism for SIP signaling. It is primarily meant to
provide a way to cleanup old state in proxies that are holding provide a way to cleanup old state in proxies that are holding
call state for calls from failed endpoints which were never call state for calls from failed endpoints which were never
terminated normally. Despite its name, the session timer is not a terminated normally. Despite its name, the session timer is not a
mechanism for detecting a network failure mid-call. Session mechanism for detecting a network failure mid-call. Session
timers introduces a fair bit of complexity for relatively little timers introduces a fair bit of complexity for relatively little
gain, and has thus seen little deployment. gain, and has thus seen little deployment.
RFC 4168, SCTP as a Transport for SIP (S): RFC 4168 [36] defines how RFC 4168, SCTP as a Transport for SIP (S): RFC 4168 [36] defines how
to carry SIP messages over the Stream Control Transmission to carry SIP messages over the Stream Control Transmission
Protocol (SCTP). SCTP has seen very limited usage for SIP Protocol (SCTP). SCTP has seen very limited usage for SIP
transport. transport.
RFC 4244, An Extension to SIP for Request History Information RFC 4244, An Extension to SIP for Request History Information (S):
(S): RFC 4244 [37] defines the History-Info header field, which RFC 4244 [37] defines the History-Info header field, which
indicates information on how a call came to be routed to a indicates information on how a call came to be routed to a
particular destination. Its primary application was in support of particular destination. Its primary application was in support of
voicemail services. voicemail services.
RFC 4145, TCP-Based Media Transport in the Session Description RFC 4145, TCP-Based Media Transport in the Session Description
Protocol (SDP) (S): RFC 4145 [86] defines an extension to SDP for Protocol (SDP) (S): RFC 4145 [86] defines an extension to SDP for
setting up TCP-based sessions between user agents. It defines who setting up TCP-based sessions between user agents. It defines who
sets up the connection and how its lifecycle is managed. It has sets up the connection and how its lifecycle is managed. It has
seen relatively little usage due to the small number of media seen relatively little usage due to the small number of media
types to date which use TCP. types to date which use TCP.
RFC 4091, The Alternative Network Address Types (ANAT) Semantics for RFC 4091, The Alternative Network Address Types (ANAT) Semantics for
the Session Description Protocol (SDP) Grouping Framework (S): RFC the Session Description Protocol (SDP) Grouping Framework (S): RFC
4091 [87] defines a mechanism for including both IPv4 and IPv6 4091 [87] defines a mechanism for including both IPv4 and IPv6
addresses for a media session as alternates. addresses for a media session as alternates.
RFC XXXX, SDP Media Capabilities Negotiation (S): RFC XXXX [106]
defines an extension to the SDP capability negotiation framework
[105] for negotiating codecs, codec parameters, and media streams.
6. NAT Traversal
These SIP extensions are primarily aimed at addressing NAT traversal
for SIP.
RFC XXXX, Interactive Connectivity Establishment (ICE) (S): RFC XXXX
[5] defines a technique for NAT traversal of media sessions for
protocols that make use of the offer/answer model. This
specification is the IETF recommended mechanism for NAT traversal
for SIP media streams, and is meant to be used even by endpoints
which are themselves never behind a NAT. A SIP option tag and
media feature tag RFC XXXX [108] have been defined for use with
ICE.
RFC XXXX, TCP Candidates with Interactive Connectivity Establishment RFC XXXX, TCP Candidates with Interactive Connectivity Establishment
(ICE) (S): RFC XXXX [88] specifies the usage of ICE for TCP streams. (ICE) (S): RFC XXXX [88] specifies the usage of ICE for TCP streams.
This allows for selection of RTP-based voice ontop of TCP only This allows for selection of RTP-based voice ontop of TCP only
when NAT or firewalls would prevent UDP-based voice from working. when NAT or firewalls would prevent UDP-based voice from working.
6. Minor Extensions RFC 3605, Real Time Control Protocol (RTCP) Attribute in the Session
Description Protocol (SDP) (S): RFC 3605 [80] defines a way to
explicitly signal, within an SDP message, the IP address and port
for RTCP, rather than using the port+1 rule in the Real Time
Transport Protocol (RTP) [3]. It is needed for devices behind NAT
and used by ICE.
RFC XXXX, Managing Client Initiated Connections through SIP (S): RFC
XXXX [21], also known as SIP outbound, defines important changes
to the SIP registration mechanism which enable delivery of SIP
messages towards a UA when it is behind a NAT. This specification
is the cornerstone of the SIP NAT traversal strategy.
RFC 3581, An Extension to SIP for Symmetric Response Routing (S):
RFC 3581 [17] defines the rport parameter of the Via header. It
is an essential piece of getting SIP through NAT. NAT traversal
for SIP is considered a core part of the specifications.
RFC XXXX, Obtaining and Using Globally Routable User Agent
Identifiers (GRUU) in SIP (S): RFC XXXX [20] defines a mechanism for
directing requests towards a specific UA instance. GRUU is
essential for features like transfer and provides another piece of
the SIP NAT traversal story.
7. Minor Extensions
These SIP extensions don't fit easily into a single specific use These SIP extensions don't fit easily into a single specific use
case. They have somewhat general applicability, but they solve a case. They have somewhat general applicability, but they solve a
relatively small problem or provide an optimization. relatively small problem or provide an optimization.
RFC 4488, Suppression of the SIP REFER Implicit Subscription (S): RFC RFC 4488, Suppression of the SIP REFER Implicit Subscription (S):
4488 [38] defines an enhancement to REFER. REFER normally creates RFC 4488 [38] defines an enhancement to REFER. REFER normally
an implicit subscription to the target of the REFER. This creates an implicit subscription to the target of the REFER. This
subscription is used to pass back updates on the progress of the subscription is used to pass back updates on the progress of the
referral. This extension allows that implicit subscription to be referral. This extension allows that implicit subscription to be
bypassed as an optimization. bypassed as an optimization.
RFC 4538, Request Authorization through Dialog Identification in SIP RFC 4538, Request Authorization through Dialog Identification in SIP
(S): RFC 4538 [39] provides a mechanism that allows a UAS to (S): RFC 4538 [39] provides a mechanism that allows a UAS to
authorize a request because the requestor proves it knows a dialog authorize a request because the requestor proves it knows a dialog
that is in progress with the UAS. The specification is useful in that is in progress with the UAS. The specification is useful in
conjunction with the SIP application interaction framework [77]. conjunction with the SIP application interaction framework [77].
RFC 4508, Conveying Feature Tags with the REFER Method in SIP RFC 4508, Conveying Feature Tags with the REFER Method in SIP (S):
(S): RFC 4508 [40] defines a mechanism for carrying RFC 3840 RFC 4508 [40] defines a mechanism for carrying RFC 3840 feature
feature tags in REFER. It is useful for informing the target of tags in REFER. It is useful for informing the target of the REFER
the REFER about the characteristics of the REFER target. about the characteristics of the REFER target.
RFC XXXX, Requesting Answer Modes for SIP (S): RFC XXXX [41] defines RFC XXXX, Requesting Answer Modes for SIP (S): RFC XXXX [41] defines
an extension for indicating to the called party whether or not the an extension for indicating to the called party whether or not the
phone should ring and/or be answered immediately. This is useful phone should ring and/or be answered immediately. This is useful
for push-to-talk and for diagnostic applications. for push-to-talk and for diagnostic applications.
RFC XXXX, Rejecting Anonymous Requests in SIP (S): RFC XXXX [43] RFC XXXX, Rejecting Anonymous Requests in SIP (S): RFC XXXX [43]
defines a mechanism for a called party to indicate to the calling defines a mechanism for a called party to indicate to the calling
party that a call was rejected since the caller was anonymous. party that a call was rejected since the caller was anonymous.
This is needed for implementation of the Anonymous Call Rejection This is needed for implementation of the Anonymous Call Rejection
skipping to change at page 11, line 47 skipping to change at page 13, line 11
dereferences the URL to obtain the object. The specification has dereferences the URL to obtain the object. The specification has
potential applicability for sending large instant messages, but potential applicability for sending large instant messages, but
has yet to find much actual use. has yet to find much actual use.
RFC 3890, A Transport Independent Bandwidth Modifier for the Session RFC 3890, A Transport Independent Bandwidth Modifier for the Session
Description Protocol (SDP) (S): RFC 3890 [90] specifies an SDP Description Protocol (SDP) (S): RFC 3890 [90] specifies an SDP
extension that allows for the description of the bandwidth for a extension that allows for the description of the bandwidth for a
media session that is independent of the underlying transport media session that is independent of the underlying transport
mechanism. It has seen relatively little usage. mechanism. It has seen relatively little usage.
RFC XXXX, Session Description Protocol (SDP) Format for Binary Floor RFC 4583, Session Description Protocol (SDP) Format for Binary Floor
Control Protocol (BFCP) Streams (S): RFC XXXX [91] defines a Control Protocol (BFCP) Streams (S): RFC 4583 [91] defines a
mechanism in SDP to signal floor control streams that use BFCP. mechanism in SDP to signal floor control streams that use BFCP.
It is used for Push-To-Talk and conference floor control. It is used for Push-To-Talk and conference floor control.
RFC XXXX, Connectivity Preconditions for Session Description Protocol RFC XXXX, Connectivity Preconditions for Session Description Protocol
Media Streams (S): RFC XXXX [93] defines a usage of the precondition Media Streams (S): RFC XXXX [93] defines a usage of the precondition
framework [59]. The connectivity precondition makes sure that the framework [59]. The connectivity precondition makes sure that the
session doesn't get established until actual packet connectivity session doesn't get established until actual packet connectivity
is checked. is checked.
RFC XXXX, The SDP (Session Description Protocol) Content Attribute RFC 4796, The SDP (Session Description Protocol) Content Attribute
(S): RFC XXXX [94] defines an SDP attribute for describing the (S): RFC 4796 [94] defines an SDP attribute for describing the
purpose of a media stream. Examples include a slide view, the purpose of a media stream. Examples include a slide view, the
speaker, a sign language feed, and so on. speaker, a sign language feed, and so on.
7. Conferencing 8. Conferencing
Numerous SIP and SDP extensions are aimed at conferencing as their Numerous SIP and SDP extensions are aimed at conferencing as their
primary application. primary application.
RFC 4574, The SDP (Session Description Protocol) Label Attribute RFC 4574, The SDP (Session Description Protocol) Label Attribute
(S): RFC 4574 [95] defines an SDP attribute for providing an opaque (S): RFC 4574 [95] defines an SDP attribute for providing an opaque
label for media streams. These labels can be referred to by label for media streams. These labels can be referred to by
external documents, and in particular, by conference policy external documents, and in particular, by conference policy
documents. This allows a UA to tie together documents it may documents. This allows a UA to tie together documents it may
obtain through conferencing mechanisms to media streams to which obtain through conferencing mechanisms to media streams to which
they refer. they refer.
RFC 3911, The SIP Join Header Field (S): RFC 3911 [49] defines the RFC 3911, The SIP Join Header Field (S): RFC 3911 [49] defines the
Join header field. When sent in an INVITE, it causes the Join header field. When sent in an INVITE, it causes the
recipient to join the resulting dialog into a conference with recipient to join the resulting dialog into a conference with
another dialog in progress. another dialog in progress.
RFC 4575, A SIP Event Package for Conference State (S): RFC 4575 [56] RFC 4575, A SIP Event Package for Conference State (S): RFC 4575
defines a mechanism for learning about changes in conference [56] defines a mechanism for learning about changes in conference
state, including group membership. state, including group membership.
RFC XXXX, Conference Establishment Using Request-Contained Lists in RFC XXXX, Conference Establishment Using Request-Contained Lists in
SIP (S): RFC XXXX [70] is similar to [68]. However, instead of SIP (S): RFC XXXX [70] is similar to [68]. However, instead of
subscribing to the resource, an INVITE request is sent to the subscribing to the resource, an INVITE request is sent to the
resource, and it will act as a conference focus and generate an resource, and it will act as a conference focus and generate an
invitation to each recipient in the list. invitation to each recipient in the list.
8. Call Control Primitives 9. Call Control Primitives
Numerous SIP extensions provide a toolkit of dialog and call Numerous SIP extensions provide a toolkit of dialog and call
management techniques. These techniques have been combined together management techniques. These techniques have been combined together
to build many SIP-based services. to build many SIP-based services.
RFC 3515, The REFER Method (S): REFER [45] defines a mechanism for RFC 3515, The REFER Method (S): REFER [45] defines a mechanism for
asking a user agent to send a SIP request. Its a form of SIP asking a user agent to send a SIP request. Its a form of SIP
remote control, and is the primary tool used for call transfer in remote control, and is the primary tool used for call transfer in
SIP. SIP.
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RFC 3892, The SIP Referred-By Mechanism (S): RFC 3892 [48] defines RFC 3892, The SIP Referred-By Mechanism (S): RFC 3892 [48] defines
the Referred-By header field. It is used in requests triggered by the Referred-By header field. It is used in requests triggered by
REFER, and provides the identity of the referring party to the REFER, and provides the identity of the referring party to the
referred-to party. referred-to party.
RFC 4117, Transcoding Services Invocation in SIP Using Third Party RFC 4117, Transcoding Services Invocation in SIP Using Third Party
Call Control (I): RFC 4117 [50] defines how to use 3pcc for the Call Control (I): RFC 4117 [50] defines how to use 3pcc for the
purposes of invoking transcoding services for a call. purposes of invoking transcoding services for a call.
9. Event Framework and Packages 10. Event Framework and Packages
RFC 3265 defines a basic framework for event notification in SIP. It RFC 3265 defines a basic framework for event notification in SIP. It
introduces the notion of an event package, which is a collection of introduces the notion of an event package, which is a collection of
related state and event information. Much of the state and events in related state and event information. Much of the state and events in
SIP systems have event packages, allowing other entities to learn SIP systems have event packages, allowing other entities to learn
about changes in that state. about changes in that state.
RFC 3903, SIP Extension for Event State Publication (S): RFC 3903 RFC 3903, SIP Extension for Event State Publication (S): RFC 3903
[51] defines the PUBLISH method. It is not an event package, but [51] defines the PUBLISH method. It is not an event package, but
is used by all event packages as a mechanism for pushing an event is used by all event packages as a mechanism for pushing an event
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RFC 3680, A SIP Event Package for Registrations (S): RFC 3680 [52] RFC 3680, A SIP Event Package for Registrations (S): RFC 3680 [52]
defines an event package for finding out about changes in defines an event package for finding out about changes in
registration state. registration state.
RFC 3842, A Message Summary and Message Waiting Indication Event RFC 3842, A Message Summary and Message Waiting Indication Event
Package for SIP (S): RFC 3842 [65] defines a way for a user agent to Package for SIP (S): RFC 3842 [65] defines a way for a user agent to
find out about voicemails and other messages that are waiting for find out about voicemails and other messages that are waiting for
it. Its primary purpose is to enable the voicemail waiting lamp it. Its primary purpose is to enable the voicemail waiting lamp
on most business telephones. on most business telephones.
RFC 3856, A Presence Event Package for SIP (S): RFC 3856 [53] defines RFC 3856, A Presence Event Package for SIP (S): RFC 3856 [53]
an event package for indicating user presence through SIP. defines an event package for indicating user presence through SIP.
RFC 3857, A Watcher Information Event Template Package for SIP RFC 3857, A Watcher Information Event Template Package for SIP (S):
(S): RFC 3857 [54], also known as winfo, provides a mechanism for RFC 3857 [54], also known as winfo, provides a mechanism for a
a user agent to find out what subscriptions are in place for a user agent to find out what subscriptions are in place for a
particular event package. Its primary usage is with presence, but particular event package. Its primary usage is with presence, but
it can be used with any event package. it can be used with any event package.
RFC 4235, An INVITE Initiated Dialog Event Package for SIP (S): RFC RFC 4235, An INVITE Initiated Dialog Event Package for SIP (S): RFC
4235 [55] defines an event package for learning the state of the 4235 [55] defines an event package for learning the state of the
dialogs in progress at a user agent. dialogs in progress at a user agent, and is one of several RFCs
starting with the important number 42 [42].
RFC 4575, A SIP Event Package for Conference State (S): RFC 4575 [56] RFC 4575, A SIP Event Package for Conference State (S): RFC 4575
defines a mechanism for learning about changes in conference [56] defines a mechanism for learning about changes in conference
state, including group membership. state, including group membership.
RFC XXXX, A SIP Event Package for Keypress Stimulus (KPML) (S): RFC RFC 4730, A SIP Event Package for Keypress Stimulus (KPML) (S): RFC
XXXX [57] defines a way for an application in the network to 4730 [57] defines a way for an application in the network to
subscribe to the set of keypresses made on the keypad of a subscribe to the set of keypresses made on the keypad of a
traditional telephone. traditional telephone.
RFC XXXX, SIP Event Package for Voice Quality Reporting (S): RFC XXXX RFC XXXX, SIP Event Package for Voice Quality Reporting (S): RFC
[58] defines a SIP event package that enables the collection and XXXX [58] defines a SIP event package that enables the collection
reporting of metrics that measure the quality for Voice over and reporting of metrics that measure the quality for Voice over
Internet Protocol (VoIP) sessions. Internet Protocol (VoIP) sessions.
RFC XXXX, A Session Initiation Protocol (SIP) Event Package for RFC XXXX, A Session Initiation Protocol (SIP) Event Package for
Session-Specific Session Policies (S): RFC XXXX [96] defines a SIP Session-Specific Session Policies (S): RFC XXXX [96] defines a SIP
event package that allows a proxy to notify a user agent about its event package that allows a proxy to notify a user agent about its
desire for the UA to use certain codecs or generally obey certain desire for the UA to use certain codecs or generally obey certain
media session policies. media session policies.
RFC XXXX, The Session Initiation Protocol (SIP) Pending Additions RFC XXXX, The Session Initiation Protocol (SIP) Pending Additions
Event Package (S): RFC XXXX [103] defines a SIP event package that Event Package (S): RFC XXXX [103] defines a SIP event package that
allows a UA to learn whether consent has been given for the allows a UA to learn whether consent has been given for the
addition of an address to a SIP "mailing list". It is used in addition of an address to a SIP "mailing list". It is used in
conjunction with the SIP framework for consent [101]. conjunction with the SIP framework for consent [101].
10. Quality of Service 11. Quality of Service
Several specifications concern themselves with the interactions of Several specifications concern themselves with the interactions of
SIP with network Quality of Service (QoS) mechanisms. SIP with network Quality of Service (QoS) mechanisms.
RFC 3312, Integration of Resource Management and SIP (S): RFC 3312 RFC 3312, Integration of Resource Management and SIP (S): RFC 3312
[59], updated by RFC 4032 [60] defines a way to make sure that the [59], updated by RFC 4032 [60] defines a way to make sure that the
phone of the called party doesn't ring until a QoS reservation has phone of the called party doesn't ring until a QoS reservation has
been installed in the network. It does so by defining a general been installed in the network. It does so by defining a general
preconditions framework, which defines conditions that must be preconditions framework, which defines conditions that must be
true in order for a SIP session to proceed true in order for a SIP session to proceed
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providers network. This specification is sometimes referred to as providers network. This specification is sometimes referred to as
the SIP walled garden specification by the truly paranoid androids the SIP walled garden specification by the truly paranoid androids
in the SIP community. This is because it requires coupling of in the SIP community. This is because it requires coupling of
signaling and the underlying IP network. signaling and the underlying IP network.
RFC 3524, Mapping of Media Streams to Resource Reservation Flows RFC 3524, Mapping of Media Streams to Resource Reservation Flows
(S): RFC 3524 [97] defines a usage of the SDP grouping framework for (S): RFC 3524 [97] defines a usage of the SDP grouping framework for
indicating that a set of media streams should be handled by a indicating that a set of media streams should be handled by a
single resource reservation. single resource reservation.
11. Operations and Management 12. Operations and Management
Several specifications have been defined to support operations and Several specifications have been defined to support operations and
management of SIP systems. These include mechanisms for management of SIP systems. These include mechanisms for
configuration and network diagnostics. configuration and network diagnostics.
RFC XXXX, Diagnostic Responses for SIP Hop Limit Errors (S): RFC XXXX RFC XXXX, Diagnostic Responses for SIP Hop Limit Errors (S): RFC
[98] defines a mechanism for including diagnostic information in a XXXX [98] defines a mechanism for including diagnostic information
483 response. This response is sent when the hop-count of a SIP in a 483 response. This response is sent when the hop-count of a
request was exceeded. SIP request was exceeded.
RFC XXXX, A Framework for SIP User Agent Profile Delivery (S): RFC RFC XXXX, A Framework for SIP User Agent Profile Delivery (S): RFC
XXXX [62] defines a mechanism that allows a SIP user agent to XXXX [62] defines a mechanism that allows a SIP user agent to
bootstrap its configuration from the network, and receive updates bootstrap its configuration from the network, and receive updates
to its configuration should it change. This is considered an to its configuration should it change. This is considered an
essential piece of deploying a usable SIP network. essential piece of deploying a usable SIP network.
RFC XXXX, Extensions to the Session Initiation Protocol (SIP) User RFC XXXX, Extensions to the Session Initiation Protocol (SIP) User
Agent Profile Delivery Change Notification Event Package for the Agent Profile Delivery Change Notification Event Package for the
Extensible Markup Language Language Configuration Access Protocol Extensible Markup Language Language Configuration Access Protocol
(XCAP) (S): RFC XXXX [63] defines an extension to [62] for learning (XCAP) (S): RFC XXXX [63] defines an extension to [62] for learning
about changes in documents managed by XCAP. about changes in documents managed by XCAP.
RFC XXXX, SIP Event Package for Voice Quality Reporting (S): RFC XXXX RFC XXXX, SIP Event Package for Voice Quality Reporting (S): RFC
[58] defines a SIP event package that enables the collection and XXXX [58] defines a SIP event package that enables the collection
reporting of metrics that measure the quality for Voice over and reporting of metrics that measure the quality for Voice over
Internet Protocol (VoIP) sessions. Internet Protocol (VoIP) sessions.
12. SIP Compression 13. SIP Compression
Sigcomp [6] was defined to allow compression of SIP messages over low Sigcomp [6] was defined to allow compression of SIP messages over low
bandwidth links. Sigcomp is not formally part of SIP. However, bandwidth links. Sigcomp is not formally part of SIP. However,
usage of Sigcomp with SIP has required extensions to SIP. usage of Sigcomp with SIP has required extensions to SIP.
RFC 3486, Compressing SIP (S): RFC 3486 [64] defines a SIP URI RFC 3486, Compressing SIP (S): RFC 3486 [64] defines a SIP URI
parameter that can be used to indicate that a SIP server supports parameter that can be used to indicate that a SIP server supports
Sigcomp. Sigcomp.
13. SIP Service URIs 14. SIP Service URIs
Several extensions define well-known services that can be invoked by Several extensions define well-known services that can be invoked by
constructing requests with the specific structures for the Request constructing requests with the specific structures for the Request
URI, resulting in specific behaviors at the UAS. URI, resulting in specific behaviors at the UAS.
RFC 3087, Control of Service Context using Request URI (I): RFC 3087 RFC 3087, Control of Service Context using Request URI (I): RFC 3087
[66] introduced the context of using Request URIs, encoded [66] introduced the context of using Request URIs, encoded
appropriately, to invoke services. appropriately, to invoke services.
RFC 4662, A SIP Event Notification Extension for Resource Lists RFC 4662, A SIP Event Notification Extension for Resource Lists (S):
(S): RFC 4662 [67] defines a resource called a Resource List RFC 4662 [67] defines a resource called a Resource List Server. A
Server. A client can send a subscribe to this server. The server client can send a subscribe to this server. The server will
will generate a series of subscriptions, and compile the resulting generate a series of subscriptions, and compile the resulting
information and send it back to the subscriber. The set of information and send it back to the subscriber. The set of
resources that the RLS will subscribe to is a property of the resources that the RLS will subscribe to is a property of the
request URI in the SUBSCRIBE request. request URI in the SUBSCRIBE request.
RFC XXXX, Subscriptions To Request-Contained Resource Lists in SIP RFC XXXX, Subscriptions To Request-Contained Resource Lists in SIP
(S): RFC XXXX [68] allows a client to subscribe to a resource called (S): RFC XXXX [68] allows a client to subscribe to a resource called
a Resource List Server. This server will generate a series of a Resource List Server. This server will generate a series of
subscriptions, and compile the resulting information and send it subscriptions, and compile the resulting information and send it
back to the subscriber. For this specification, the list of back to the subscriber. For this specification, the list of
things to subscribe to is in the body of the SUBSCRIBE request. things to subscribe to is in the body of the SUBSCRIBE request.
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resource, and it will act as a conference focus and generate an resource, and it will act as a conference focus and generate an
invitation to each recipient in the list. invitation to each recipient in the list.
RFC 4240, Basic Network Media Services with SIP (I): RFC 4240 [99] RFC 4240, Basic Network Media Services with SIP (I): RFC 4240 [99]
defines a way for SIP application servers to invoke announcement defines a way for SIP application servers to invoke announcement
and conferencing services from a media server. This is and conferencing services from a media server. This is
accomplished through a set of defined URI parameters which tell accomplished through a set of defined URI parameters which tell
the media server what to do, such as what file to play and what the media server what to do, such as what file to play and what
language to render it in. language to render it in.
14. Security Mechanisms 15. Security Mechanisms
Several extensions provide additional security features to SIP. Several extensions provide additional security features to SIP.
RFC 3853, S/MIME AES Requirement for SIP (S): RFC 3853 [71] is a RFC 3853, S/MIME AES Requirement for SIP (S): RFC 3853 [71] is a
brief specification that updates the cryptography mechanisms used brief specification that updates the cryptography mechanisms used
in SIP S/MIME. However, SIP S/MIME has seen very little in SIP S/MIME. However, SIP S/MIME has seen very little
deployment. deployment.
RFC XXXX, Certificate Management Service for The Session Initiation RFC XXXX, Certificate Management Service for The Session Initiation
Protocol (SIP) (S): RFC XXXX [100] defines a certificate service for Protocol (SIP) (S): RFC XXXX [100] defines a certificate service for
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RFC XXXX, The Session Initiation Protocol (SIP) Pending Additions RFC XXXX, The Session Initiation Protocol (SIP) Pending Additions
Event Package (S): RFC XXXX [103] defines a SIP event package that Event Package (S): RFC XXXX [103] defines a SIP event package that
allows a UA to learn whether consent has been given for the allows a UA to learn whether consent has been given for the
addition of an address to a SIP "mailing list". It is used in addition of an address to a SIP "mailing list". It is used in
conjunction with the SIP framework for consent [101]. conjunction with the SIP framework for consent [101].
RFC 3329, Security Mechanism Agreement for SIP (S): RFC 3329 [72] RFC 3329, Security Mechanism Agreement for SIP (S): RFC 3329 [72]
defines a mechanism to prevent bid-down attacks in conjunction defines a mechanism to prevent bid-down attacks in conjunction
with SIP authentication. The mechanism has seen very limited with SIP authentication. The mechanism has seen very limited
deployment. It was defined as part of the 3gpp IMS specification deployment. It was defined as part of the 3gpp IMS specification
suite, and is needed only when there are a multiplicity of suite [109], and is needed only when there are a multiplicity of
security mechanisms deployed at a particular server. In practice, security mechanisms deployed at a particular server. In practice,
this has not been the case. this has not been the case.
RFC XXXX, End-to-Middle Security in SIP (S): RFC XXXX [73] defines RFC XXXX, End-to-Middle Security in SIP (S): RFC XXXX [73] defines
mechanisms for encrypting content from user agents to specific mechanisms for providing confidentiality and integrity for SIP
network intermediaries. message bodies sent from user agents to specific network
intermediaries.
RFC 4572, Connection-Oriented Media Transport over the Transport RFC 4572, Connection-Oriented Media Transport over the Transport
Layer Security (TLS) Protocol in the Session Description Protocol Layer Security (TLS) Protocol in the Session Description Protocol
(SDP) (S): RFC 4572 [104] specifies a mechanism for signaling TLS- (SDP) (S): RFC 4572 [104] specifies a mechanism for signaling TLS-
based media streams between endpoints. It expands the TCP-based based media streams between endpoints. It expands the TCP-based
media signaling parameters defined in [86] to include fingerprint media signaling parameters defined in [86] to include fingerprint
information for TLS streams, so that TLS can operate between end information for TLS streams, so that TLS can operate between end
hosts using self-signed certificates. hosts using self-signed certificates.
RFC XXXX, Security Preconditions for Session Description Protocol RFC XXXX, Security Preconditions for Session Description Protocol
Media Streams (S): RFC XXXX [92] defines a precondition for use with Media Streams (S): RFC XXXX [92] defines a precondition for use with
the preconditions framework [59]. The security precondition the preconditions framework [59]. The security precondition
prevents a session from being established until a security media prevents a session from being established until a security media
stream is set up. stream is set up.
15. Instant Messaging and Presence 16. Instant Messaging, Presence and Multimedia
SIP provides extensions for instant messaging and presence. SIP provides extensions for instant messaging, presence, and
multimedia.
RFC 3428, SIP Extension for Instant Messaging (S): RFC 3428 [74] RFC 3428, SIP Extension for Instant Messaging (S): RFC 3428 [74]
defines the MESSAGE method, used for sending a page mode instant defines the MESSAGE method, used for sending an instant message
message. without setting up a session (sometimes called "page mode").
RFC 3856, A Presence Event Package for SIP (S): RFC 3856 [53] defines RFC 3856, A Presence Event Package for SIP (S): RFC 3856 [53]
an event package for indicating user presence through SIP. defines an event package for indicating user presence through SIP.
RFC 3857, A Watcher Information Event Template Package for SIP RFC 3857, A Watcher Information Event Template Package for SIP (S):
(S): RFC 3857 [54], also known as winfo, provides a mechanism for RFC 3857 [54], also known as winfo, provides a mechanism for a
a user agent to find out what subscriptions are in place for a user agent to find out what subscriptions are in place for a
particular event package. Its primary usage is with presence, but particular event package. Its primary usage is with presence, but
it can be used with any event package. it can be used with any event package.
16. Emergency Services RFC XXXX, A Session Description Protocol (SDP) Offer/Answer Mechanism
to Enable File Transfer (S): RFC XXXX [107] defines a mechanism for
signaling a file transfer session with SIP.
17. Emergency Services
Emergency services here covers both emergency calling (for example, Emergency services here covers both emergency calling (for example,
911 in the United States), and pre-emption services, which allow 911 in the United States), and pre-emption services, which allow
authorized individuals to gain access to network resources in time of authorized individuals to gain access to network resources in time of
emergency. emergency.
RFC 4411, Extending the SIP Reason Header for Preemption Events RFC 4411, Extending the SIP Reason Header for Preemption Events (S):
(S): RFC 4411 [75] defines an extension to the Reason header, RFC 4411 [75] defines an extension to the Reason header, allowing
allowing a UA to know that its dialog was torn down because a a UA to know that its dialog was torn down because a higher
higher priority session came through. priority session came through.
RFC 4412, Communications Resource Priority for SIP (S): RFC 4412 [76] RFC 4412, Communications Resource Priority for SIP (S): RFC 4412
defines a new header field, Resource-Priority, that allows a [76] defines a new header field, Resource-Priority, that allows a
session to get priority treatment from the network. session to get priority treatment from the network.
17. Security Considerations 18. Security Considerations
This specification is an overview of existing specifications, and This specification is an overview of existing specifications, and
does not introduce any security considerations on its own. does not introduce any security considerations on its own. Of
course, the world would be far more secure if everyone would follow
one simple rule: "Don't Panic!" [42].
18. IANA Considerations 19. IANA Considerations
None. None.
19. Informative References 20. Acknowledgements
The author would like to thank Spencer Dawkins for his comments on
this specification.
21. Informative References
[1] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., [1] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A.,
Peterson, J., Sparks, R., Handley, M., and E. Schooler, "SIP: Peterson, J., Sparks, R., Handley, M., and E. Schooler, "SIP:
Session Initiation Protocol", RFC 3261, June 2002. Session Initiation Protocol", RFC 3261, June 2002.
[2] Bradner, S., "The Internet Standards Process -- Revision 3", [2] Bradner, S., "The Internet Standards Process -- Revision 3",
BCP 9, RFC 2026, October 1996. BCP 9, RFC 2026, October 1996.
[3] Schulzrinne, H., Casner, S., Frederick, R., and V. Jacobson, [3] Schulzrinne, H., Casner, S., Frederick, R., and V. Jacobson,
"RTP: A Transport Protocol for Real-Time Applications", "RTP: A Transport Protocol for Real-Time Applications",
RFC 3550, July 2003. RFC 3550, July 2003.
[4] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model with [4] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model with
Session Description Protocol (SDP)", RFC 3264, June 2002. Session Description Protocol (SDP)", RFC 3264, June 2002.
[5] Rosenberg, J., "Interactive Connectivity Establishment (ICE): [5] Rosenberg, J., "Interactive Connectivity Establishment (ICE):
A Methodology for Network Address Translator (NAT) Traversal A Methodology for Network Address Translator (NAT) Traversal
for Offer/Answer Protocols", draft-ietf-mmusic-ice-11 (work in for Offer/Answer Protocols", draft-ietf-mmusic-ice-13 (work in
progress), October 2006. progress), January 2007.
[6] Price, R., Bormann, C., Christoffersson, J., Hannu, H., Liu, [6] Price, R., Bormann, C., Christoffersson, J., Hannu, H., Liu,
Z., and J. Rosenberg, "Signaling Compression (SigComp)", Z., and J. Rosenberg, "Signaling Compression (SigComp)",
RFC 3320, January 2003. RFC 3320, January 2003.
[7] Peterson, J., "Session Initiation Protocol (SIP) Authenticated [7] Peterson, J., "Session Initiation Protocol (SIP) Authenticated
Identity Body (AIB) Format", RFC 3893, September 2004. Identity Body (AIB) Format", RFC 3893, September 2004.
[8] Mankin, A., Bradner, S., Mahy, R., Willis, D., Ott, J., and B. [8] Mankin, A., Bradner, S., Mahy, R., Willis, D., Ott, J., and B.
Rosen, "Change Process for the Session Initiation Protocol Rosen, "Change Process for the Session Initiation Protocol
skipping to change at page 21, line 30 skipping to change at page 23, line 11
[18] Sparks, R., "Actions Addressing Identified Issues with the [18] Sparks, R., "Actions Addressing Identified Issues with the
Session Initiation Protocol's (SIP) Non-INVITE Transaction", Session Initiation Protocol's (SIP) Non-INVITE Transaction",
RFC 4320, January 2006. RFC 4320, January 2006.
[19] Peterson, J. and C. Jennings, "Enhancements for Authenticated [19] Peterson, J. and C. Jennings, "Enhancements for Authenticated
Identity Management in the Session Initiation Protocol (SIP)", Identity Management in the Session Initiation Protocol (SIP)",
RFC 4474, August 2006. RFC 4474, August 2006.
[20] Rosenberg, J., "Obtaining and Using Globally Routable User [20] Rosenberg, J., "Obtaining and Using Globally Routable User
Agent (UA) URIs (GRUU) in the Session Initiation Protocol Agent (UA) URIs (GRUU) in the Session Initiation Protocol
(SIP)", draft-ietf-sip-gruu-10 (work in progress), (SIP)", draft-ietf-sip-gruu-11 (work in progress),
August 2006. October 2006.
[21] Jennings, C. and R. Mahy, "Managing Client Initiated [21] Jennings, C. and R. Mahy, "Managing Client Initiated
Connections in the Session Initiation Protocol (SIP)", Connections in the Session Initiation Protocol (SIP)",
draft-ietf-sip-outbound-04 (work in progress), June 2006. draft-ietf-sip-outbound-07 (work in progress), January 2007.
[22] Petrack, S. and L. Conroy, "The PINT Service Protocol: [22] Petrack, S. and L. Conroy, "The PINT Service Protocol:
Extensions to SIP and SDP for IP Access to Telephone Call Extensions to SIP and SDP for IP Access to Telephone Call
Services", RFC 2848, June 2000. Services", RFC 2848, June 2000.
[23] Gurbani, V., Brusilovsky, A., Faynberg, I., Gato, J., Lu, H., [23] Gurbani, V., Brusilovsky, A., Faynberg, I., Gato, J., Lu, H.,
and M. Unmehopa, "The SPIRITS (Services in PSTN requesting and M. Unmehopa, "The SPIRITS (Services in PSTN requesting
Internet Services) Protocol", RFC 3910, October 2004. Internet Services) Protocol", RFC 3910, October 2004.
[24] Vemuri, A. and J. Peterson, "Session Initiation Protocol for [24] Vemuri, A. and J. Peterson, "Session Initiation Protocol for
skipping to change at page 23, line 17 skipping to change at page 24, line 47
RFC 4538, June 2006. RFC 4538, June 2006.
[40] Levin, O. and A. Johnston, "Conveying Feature Tags with the [40] Levin, O. and A. Johnston, "Conveying Feature Tags with the
Session Initiation Protocol (SIP) REFER Method", RFC 4508, Session Initiation Protocol (SIP) REFER Method", RFC 4508,
May 2006. May 2006.
[41] Willis, D. and A. Allen, "Requesting Answering Modes for the [41] Willis, D. and A. Allen, "Requesting Answering Modes for the
Session Initiation Protocol (SIP)", Session Initiation Protocol (SIP)",
draft-ietf-sip-answermode-01 (work in progress), May 2006. draft-ietf-sip-answermode-01 (work in progress), May 2006.
[42] Adams, D., "The Hitchhikers Guide to the Galaxy", [42] Adams, D., "The Hitchhiker's Guide to the Galaxy",
September 1979. September 1979.
[43] Rosenberg, J., "Rejecting Anonymous Requests in the Session [43] Rosenberg, J., "Rejecting Anonymous Requests in the Session
Initiation Protocol (SIP)", draft-ietf-sip-acr-code-03 (work Initiation Protocol (SIP)", draft-ietf-sip-acr-code-04 (work
in progress), October 2006. in progress), March 2007.
[44] Camarillo, G., "Refering to Multiple Resources in the Session [44] Camarillo, G., "Referring to Multiple Resources in the Session
Initiation Protocol (SIP)", draft-ietf-sip-multiple-refer-00 Initiation Protocol (SIP)", draft-ietf-sip-multiple-refer-01
(work in progress), September 2006. (work in progress), January 2007.
[45] Sparks, R., "The Session Initiation Protocol (SIP) Refer [45] Sparks, R., "The Session Initiation Protocol (SIP) Refer
Method", RFC 3515, April 2003. Method", RFC 3515, April 2003.
[46] Rosenberg, J., Peterson, J., Schulzrinne, H., and G. [46] Rosenberg, J., Peterson, J., Schulzrinne, H., and G.
Camarillo, "Best Current Practices for Third Party Call Camarillo, "Best Current Practices for Third Party Call
Control (3pcc) in the Session Initiation Protocol (SIP)", Control (3pcc) in the Session Initiation Protocol (SIP)",
BCP 85, RFC 3725, April 2004. BCP 85, RFC 3725, April 2004.
[47] Mahy, R., Biggs, B., and R. Dean, "The Session Initiation [47] Mahy, R., Biggs, B., and R. Dean, "The Session Initiation
skipping to change at page 24, line 15 skipping to change at page 25, line 44
[52] Rosenberg, J., "A Session Initiation Protocol (SIP) Event [52] Rosenberg, J., "A Session Initiation Protocol (SIP) Event
Package for Registrations", RFC 3680, March 2004. Package for Registrations", RFC 3680, March 2004.
[53] Rosenberg, J., "A Presence Event Package for the Session [53] Rosenberg, J., "A Presence Event Package for the Session
Initiation Protocol (SIP)", RFC 3856, August 2004. Initiation Protocol (SIP)", RFC 3856, August 2004.
[54] Rosenberg, J., "A Watcher Information Event Template-Package [54] Rosenberg, J., "A Watcher Information Event Template-Package
for the Session Initiation Protocol (SIP)", RFC 3857, for the Session Initiation Protocol (SIP)", RFC 3857,
August 2004. August 2004.
[55] Santesson, S. and R. Housley, "Internet X.509 Public Key [55] Rosenberg, J., Schulzrinne, H., and R. Mahy, "An INVITE-
Infrastructure Authority Information Access Certificate Initiated Dialog Event Package for the Session Initiation
Revocation List (CRL) Extension", RFC 4325, December 2005. Protocol (SIP)", RFC 4235, November 2005.
[56] Rosenberg, J., Schulzrinne, H., and O. Levin, "A Session [56] Rosenberg, J., Schulzrinne, H., and O. Levin, "A Session
Initiation Protocol (SIP) Event Package for Conference State", Initiation Protocol (SIP) Event Package for Conference State",
RFC 4575, August 2006. RFC 4575, August 2006.
[57] Dolly, M. and E. Burger, "A Session Initiation Protocol (SIP) [57] Burger, E. and M. Dolly, "A Session Initiation Protocol (SIP)
Event Package for Key Press Stimulus (KPML)", Event Package for Key Press Stimulus (KPML)", RFC 4730,
draft-ietf-sipping-kpml-08 (work in progress), July 2006. November 2006.
[58] Pendleton, A., "Session Initiation Protocol Package for Voice [58] Pendleton, A., "Session Initiation Protocol Package for Voice
Quality Reporting Event", draft-ietf-sipping-rtcp-summary-01 Quality Reporting Event", draft-ietf-sipping-rtcp-summary-01
(work in progress), February 2006. (work in progress), February 2006.
[59] Camarillo, G., Marshall, W., and J. Rosenberg, "Integration of [59] Camarillo, G., Marshall, W., and J. Rosenberg, "Integration of
Resource Management and Session Initiation Protocol (SIP)", Resource Management and Session Initiation Protocol (SIP)",
RFC 3312, October 2002. RFC 3312, October 2002.
[60] Camarillo, G. and P. Kyzivat, "Update to the Session [60] Camarillo, G. and P. Kyzivat, "Update to the Session
Initiation Protocol (SIP) Preconditions Framework", RFC 4032, Initiation Protocol (SIP) Preconditions Framework", RFC 4032,
March 2005. March 2005.
[61] Marshall, W., "Private Session Initiation Protocol (SIP) [61] Marshall, W., "Private Session Initiation Protocol (SIP)
Extensions for Media Authorization", RFC 3313, January 2003. Extensions for Media Authorization", RFC 3313, January 2003.
[62] Petrie, D., "A Framework for Session Initiation Protocol User [62] Petrie, D. and S. Channabasappa, "A Framework for Session
Agent Profile Delivery", Initiation Protocol User Agent Profile Delivery",
draft-ietf-sipping-config-framework-09 (work in progress), draft-ietf-sipping-config-framework-10 (work in progress),
October 2006. January 2007.
[63] Petrie, D., "Extensions to the Session Initiation Protocol [63] Petrie, D., "Extensions to the Session Initiation Protocol
(SIP) User Agent Profile Delivery Change Notification Event (SIP) User Agent Profile Delivery Change Notification Event
Package for the Extensible Markup Language Language Package for the Extensible Markup Language Language
Configuration Access Protocol (XCAP)", Configuration Access Protocol (XCAP)",
draft-ietf-sip-xcap-config-00 (work in progress), draft-ietf-sip-xcap-config-00 (work in progress),
October 2006. October 2006.
[64] Camarillo, G., "Compressing the Session Initiation Protocol [64] Camarillo, G., "Compressing the Session Initiation Protocol
(SIP)", RFC 3486, February 2003. (SIP)", RFC 3486, February 2003.
skipping to change at page 25, line 21 skipping to change at page 26, line 50
[66] Campbell, B. and R. Sparks, "Control of Service Context using [66] Campbell, B. and R. Sparks, "Control of Service Context using
SIP Request-URI", RFC 3087, April 2001. SIP Request-URI", RFC 3087, April 2001.
[67] Roach, A., Campbell, B., and J. Rosenberg, "A Session [67] Roach, A., Campbell, B., and J. Rosenberg, "A Session
Initiation Protocol (SIP) Event Notification Extension for Initiation Protocol (SIP) Event Notification Extension for
Resource Lists", RFC 4662, August 2006. Resource Lists", RFC 4662, August 2006.
[68] Camarillo, G., "Subscriptions to Request-Contained Resource [68] Camarillo, G., "Subscriptions to Request-Contained Resource
Lists in the Session Initiation Protocol (SIP)", Lists in the Session Initiation Protocol (SIP)",
draft-ietf-sip-uri-list-subscribe-00 (work in progress), draft-ietf-sip-uri-list-subscribe-01 (work in progress),
September 2006. January 2007.
[69] Garcia-Martin, M. and G. Camarillo, "Multiple-Recipient [69] Garcia-Martin, M. and G. Camarillo, "Multiple-Recipient
MESSAGE Requests in the Session Initiation Protocol (SIP)", MESSAGE Requests in the Session Initiation Protocol (SIP)",
draft-ietf-sip-uri-list-message-00 (work in progress), draft-ietf-sip-uri-list-message-01 (work in progress),
September 2006. January 2007.
[70] Camarillo, G. and A. Johnston, "Conference Establishment Using [70] Camarillo, G. and A. Johnston, "Conference Establishment Using
Request-Contained Lists in the Session Initiation Protocol Request-Contained Lists in the Session Initiation Protocol
(SIP)", draft-ietf-sip-uri-list-conferencing-00 (work in (SIP)", draft-ietf-sip-uri-list-conferencing-01 (work in
progress), September 2006. progress), January 2007.
[71] Peterson, J., "S/MIME Advanced Encryption Standard (AES) [71] Peterson, J., "S/MIME Advanced Encryption Standard (AES)
Requirement for the Session Initiation Protocol (SIP)", Requirement for the Session Initiation Protocol (SIP)",
RFC 3853, July 2004. RFC 3853, July 2004.
[72] Arkko, J., Torvinen, V., Camarillo, G., Niemi, A., and T. [72] Arkko, J., Torvinen, V., Camarillo, G., Niemi, A., and T.
Haukka, "Security Mechanism Agreement for the Session Haukka, "Security Mechanism Agreement for the Session
Initiation Protocol (SIP)", RFC 3329, January 2003. Initiation Protocol (SIP)", RFC 3329, January 2003.
[73] Ono, K. and S. Tachimoto, "End-to-middle Security in the [73] Ono, K. and S. Tachimoto, "End-to-middle Security in the
Session Initiation Protocol (SIP)", draft-ietf-sip-e2m-sec-03 Session Initiation Protocol (SIP)", draft-ietf-sip-e2m-sec-04
(work in progress), September 2006. (work in progress), December 2006.
[74] Campbell, B., Rosenberg, J., Schulzrinne, H., Huitema, C., and [74] Campbell, B., Rosenberg, J., Schulzrinne, H., Huitema, C., and
D. Gurle, "Session Initiation Protocol (SIP) Extension for D. Gurle, "Session Initiation Protocol (SIP) Extension for
Instant Messaging", RFC 3428, December 2002. Instant Messaging", RFC 3428, December 2002.
[75] Polk, J., "Extending the Session Initiation Protocol (SIP) [75] Polk, J., "Extending the Session Initiation Protocol (SIP)
Reason Header for Preemption Events", RFC 4411, February 2006. Reason Header for Preemption Events", RFC 4411, February 2006.
[76] Schulzrinne, H. and J. Polk, "Communications Resource Priority [76] Schulzrinne, H. and J. Polk, "Communications Resource Priority
for the Session Initiation Protocol (SIP)", RFC 4412, for the Session Initiation Protocol (SIP)", RFC 4412,
skipping to change at page 26, line 25 skipping to change at page 28, line 6
Description Protocol", RFC 4566, July 2006. Description Protocol", RFC 4566, July 2006.
[79] Camarillo, G., Eriksson, G., Holler, J., and H. Schulzrinne, [79] Camarillo, G., Eriksson, G., Holler, J., and H. Schulzrinne,
"Grouping of Media Lines in the Session Description Protocol "Grouping of Media Lines in the Session Description Protocol
(SDP)", RFC 3388, December 2002. (SDP)", RFC 3388, December 2002.
[80] Huitema, C., "Real Time Control Protocol (RTCP) attribute in [80] Huitema, C., "Real Time Control Protocol (RTCP) attribute in
Session Description Protocol (SDP)", RFC 3605, October 2003. Session Description Protocol (SDP)", RFC 3605, October 2003.
[81] Elwell, J., "Connected Identity in the Session Initiation [81] Elwell, J., "Connected Identity in the Session Initiation
Protocol (SIP)", draft-ietf-sip-connected-identity-02 (work in Protocol (SIP)", draft-ietf-sip-connected-identity-05 (work in
progress), October 2006. progress), February 2007.
[82] Sparks, R., "Addressing an Amplification Vulnerability in [82] Sparks, R., "Addressing an Amplification Vulnerability in
Session Initiation Protocol (SIP) Forking Proxies", Session Initiation Protocol (SIP) Forking Proxies",
draft-ietf-sip-fork-loop-fix-03 (work in progress), draft-ietf-sip-fork-loop-fix-04 (work in progress),
September 2006. October 2006.
[83] Camarillo, G., "The Early Session Disposition Type for the [83] Camarillo, G., "The Early Session Disposition Type for the
Session Initiation Protocol (SIP)", RFC 3959, December 2004. Session Initiation Protocol (SIP)", RFC 3959, December 2004.
[84] Zimmerer, E., Peterson, J., Vemuri, A., Ong, L., Audet, F., [84] Zimmerer, E., Peterson, J., Vemuri, A., Ong, L., Audet, F.,
Watson, M., and M. Zonoun, "MIME media types for ISUP and QSIG Watson, M., and M. Zonoun, "MIME media types for ISUP and QSIG
Objects", RFC 3204, December 2001. Objects", RFC 3204, December 2001.
[85] Sparks, R., "Internet Media Type message/sipfrag", RFC 3420, [85] Sparks, R., "Internet Media Type message/sipfrag", RFC 3420,
November 2002. November 2002.
[86] Yon, D. and G. Camarillo, "TCP-Based Media Transport in the [86] Yon, D. and G. Camarillo, "TCP-Based Media Transport in the
Session Description Protocol (SDP)", RFC 4145, September 2005. Session Description Protocol (SDP)", RFC 4145, September 2005.
[87] Camarillo, G. and J. Rosenberg, "The Alternative Network [87] Camarillo, G. and J. Rosenberg, "The Alternative Network
Address Types (ANAT) Semantics for the Session Description Address Types (ANAT) Semantics for the Session Description
Protocol (SDP) Grouping Framework", RFC 4091, June 2005. Protocol (SDP) Grouping Framework", RFC 4091, June 2005.
[88] Rosenberg, J., "TCP Candidates with Interactive Connectivity [88] Rosenberg, J., "TCP Candidates with Interactive Connectivity
Establishment (ICE)", draft-ietf-mmusic-ice-tcp-01 (work in Establishment (ICE)", draft-ietf-mmusic-ice-tcp-02 (work in
progress), June 2006. progress), October 2006.
[89] Burger, E., "A Mechanism for Content Indirection in Session [89] Burger, E., "A Mechanism for Content Indirection in Session
Initiation Protocol (SIP) Messages", RFC 4483, May 2006. Initiation Protocol (SIP) Messages", RFC 4483, May 2006.
[90] Westerlund, M., "A Transport Independent Bandwidth Modifier [90] Westerlund, M., "A Transport Independent Bandwidth Modifier
for the Session Description Protocol (SDP)", RFC 3890, for the Session Description Protocol (SDP)", RFC 3890,
September 2004. September 2004.
[91] Camarillo, G., "Session Description Protocol (SDP) Format for [91] Camarillo, G., "Session Description Protocol (SDP) Format for
Binary Floor Control Protocol (BFCP) Streams", Binary Floor Control Protocol (BFCP) Streams", RFC 4583,
draft-ietf-mmusic-sdp-bfcp-03 (work in progress), November 2006.
December 2005.
[92] Andreasen, F. and D. Wing, "Security Preconditions for Session [92] Andreasen, F. and D. Wing, "Security Preconditions for Session
Description Protocol (SDP) Media Streams", Description Protocol (SDP) Media Streams",
draft-ietf-mmusic-securityprecondition-02 (work in progress), draft-ietf-mmusic-securityprecondition-03 (work in progress),
June 2006. October 2006.
[93] Andreasen, F., "Connectivity Preconditions for Session [93] Andreasen, F., "Connectivity Preconditions for Session
Description Protocol Media Streams", Description Protocol Media Streams",
draft-ietf-mmusic-connectivity-precon-02 (work in progress), draft-ietf-mmusic-connectivity-precon-02 (work in progress),
June 2006. June 2006.
[94] Hautakorpi, J. and G. Camarillo, "The SDP (Session Description [94] Hautakorpi, J. and G. Camarillo, "The Session Description
Protocol) Content Attribute", Protocol (SDP) Content Attribute", RFC 4796, February 2007.
draft-ietf-mmusic-sdp-media-content-06 (work in progress),
September 2006.
[95] Levin, O. and G. Camarillo, "The Session Description Protocol [95] Levin, O. and G. Camarillo, "The Session Description Protocol
(SDP) Label Attribute", RFC 4574, August 2006. (SDP) Label Attribute", RFC 4574, August 2006.
[96] Hilt, V. and G. Camarillo, "A Session Initiation Protocol [96] Hilt, V. and G. Camarillo, "A Session Initiation Protocol
(SIP) Event Package for Session-Specific Session Policies", (SIP) Event Package for Session-Specific Session Policies.",
draft-ietf-sipping-policy-package-01 (work in progress), draft-ietf-sipping-policy-package-03 (work in progress),
June 2006. February 2007.
[97] Camarillo, G. and A. Monrad, "Mapping of Media Streams to [97] Camarillo, G. and A. Monrad, "Mapping of Media Streams to
Resource Reservation Flows", RFC 3524, April 2003. Resource Reservation Flows", RFC 3524, April 2003.
[98] Lawrence, S., "Diagnostic Responses for Session Initiation [98] Lawrence, S., "Diagnostic Responses for Session Initiation
Protocol Hop Limit Errors", Protocol Hop Limit Errors",
draft-ietf-sip-hop-limit-diagnostics-03 (work in progress), draft-ietf-sip-hop-limit-diagnostics-03 (work in progress),
June 2006. June 2006.
[99] Burger, E., Van Dyke, J., and A. Spitzer, "Basic Network Media [99] Burger, E., Van Dyke, J., and A. Spitzer, "Basic Network Media
Services with SIP", RFC 4240, December 2005. Services with SIP", RFC 4240, December 2005.
[100] Jennings, C., "Certificate Management Service for The Session [100] Jennings, C., "Certificate Management Service for The Session
Initiation Protocol (SIP)", draft-ietf-sip-certs-01 (work in Initiation Protocol (SIP)", draft-ietf-sip-certs-02 (work in
progress), June 2006. progress), October 2006.
[101] Rosenberg, J., "A Framework for Consent-Based Communications [101] Rosenberg, J., "A Framework for Consent-Based Communications
in the Session Initiation Protocol (SIP)", in the Session Initiation Protocol (SIP)",
draft-ietf-sip-consent-framework-00 (work in progress), draft-ietf-sip-consent-framework-01 (work in progress),
September 2006. November 2006.
[102] Tschofenig, H., "SIP SAML Profile and Binding", [102] Tschofenig, H., "SIP SAML Profile and Binding",
draft-ietf-sip-saml-00 (work in progress), June 2006. draft-ietf-sip-saml-01 (work in progress), October 2006.
[103] Camarillo, G., "The Session Initiation Protocol (SIP) Pending [103] Camarillo, G., "The Session Initiation Protocol (SIP) Pending
Additions Event Package", Additions Event Package",
draft-ietf-sipping-pending-additions-00 (work in progress), draft-ietf-sipping-pending-additions-01 (work in progress),
September 2006. November 2006.
[104] Lennox, J., "Connection-Oriented Media Transport over the [104] Lennox, J., "Connection-Oriented Media Transport over the
Transport Layer Security (TLS) Protocol in the Session Transport Layer Security (TLS) Protocol in the Session
Description Protocol (SDP)", RFC 4572, July 2006. Description Protocol (SDP)", RFC 4572, July 2006.
[105] Andreasen, F., "SDP Capability Negotiation",
draft-ietf-mmusic-sdp-capability-negotiation-04 (work in
progress), February 2007.
[106] Andreasen, F., "SDP media capabilities Negotiation",
draft-ietf-mmusic-sdp-media-capabilities-01 (work in
progress), February 2007.
[107] Garcia-Martin, M., "A Session Description Protocol (SDP)
Offer/Answer Mechanism to Enable File Transfer",
draft-ietf-mmusic-file-transfer-mech-00 (work in progress),
December 2006.
[108] Rosenberg, J., "Indicating Support for Interactive
Connectivity Establishment (ICE) in the Session Initiation
Protocol (SIP)", draft-ietf-sip-ice-option-tag-00 (work in
progress), January 2007.
[109] 3GPP, "Internet Protocol (IP) multimedia call control protocol
based on Session Initiation Protocol (SIP) and Session
Description Protocol (SDP); Stage 3", 3GPP TS 24.229 5.18.0,
October 2006.
Author's Address Author's Address
Jonathan Rosenberg Jonathan Rosenberg
Cisco Systems Cisco
600 Lanidex Plaza Edison, NJ
Parsippany, NJ 07054
US US
Phone: +1 973 952-5000
Email: jdrosen@cisco.com Email: jdrosen@cisco.com
URI: http://www.jdrosen.net URI: http://www.jdrosen.net
Intellectual Property Statement Full Copyright Statement
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This document is subject to the rights, licenses and restrictions
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This document and the information contained herein are provided on an
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The IETF takes no position regarding the validity or scope of any The IETF takes no position regarding the validity or scope of any
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skipping to change at page 30, line 29 skipping to change at page 31, line 45
such proprietary rights by implementers or users of this such proprietary rights by implementers or users of this
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ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
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Copyright (C) The Internet Society (2006). This document is subject
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Acknowledgment Acknowledgment
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Internet Society. Administrative Support Activity (IASA).
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