draft-ietf-avt-srtp-not-mandatory-12.txt   draft-ietf-avt-srtp-not-mandatory-13.txt 
Network Working Group C. Perkins Network Working Group C.S. Perkins
Internet-Draft University of Glasgow Internet-Draft University of Glasgow
Intended status: Informational M. Westerlund Intended status: Informational M. Westerlund
Expires: August 29, 2013 Ericsson Expires: November 07, 2013 Ericsson
February 25, 2013 May 06, 2013
Securing the RTP Protocol Framework: Why RTP Does Not Mandate a Single Securing the RTP Protocol Framework: Why RTP Does Not Mandate a Single
Media Security Solution Media Security Solution
draft-ietf-avt-srtp-not-mandatory-12.txt draft-ietf-avt-srtp-not-mandatory-13.txt
Abstract Abstract
This memo discusses the problem of securing real-time multimedia This memo discusses the problem of securing real-time multimedia
sessions, and explains why the Real-time Transport Protocol (RTP), sessions, and explains why the Real-time Transport Protocol (RTP),
and the associated RTP control protocol (RTCP), do not mandate a and the associated RTP control protocol (RTCP), do not mandate a
single media security mechanism. Guidelines for designers and single media security mechanism. Guidelines for designers and
reviewers of future RTP extensions are provided, to ensure that reviewers of future RTP extensions are provided, to ensure that
appropriate security mechanisms are mandated, and that any such appropriate security mechanisms are mandated, and that any such
mechanisms are specified in a manner that conforms with the RTP mechanisms are specified in a manner that conforms with the RTP
architecture. architecture.
Status of this Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on August 29, 2013. This Internet-Draft will expire on November 07, 2013.
Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. RTP Applications and Deployment Scenarios . . . . . . . . . . . 3 2. RTP Applications and Deployment Scenarios . . . . . . . . . . 3
3. RTP Media Security . . . . . . . . . . . . . . . . . . . . . . 4 3. RTP Media Security . . . . . . . . . . . . . . . . . . . . . 4
4. RTP Session Establishment and Key Management . . . . . . . . . 5 4. RTP Session Establishment and Key Management . . . . . . . . 4
5. On the Requirement for Strong Security in Framework 5. On the Requirement for Strong Security in Framework protocols 5
protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 6. Guidelines for Securing the RTP Protocol Framework . . . . . 6
6. Guidelines for Securing the RTP Protocol Framework . . . . . . 6 7. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . 7
7. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . 7 8. Security Considerations . . . . . . . . . . . . . . . . . . . 7
8. Security Considerations . . . . . . . . . . . . . . . . . . . . 8 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 8 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 8 11. Informative References . . . . . . . . . . . . . . . . . . . 8
11. Informative References . . . . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction 1. Introduction
The Real-time Transport Protocol (RTP) [RFC3550] is widely used for The Real-time Transport Protocol (RTP) [RFC3550] is widely used for
voice over IP, Internet television, video conferencing, and other voice over IP, Internet television, video conferencing, and other
real-time and streaming media applications. Despite this use, the real-time and streaming media applications. Despite this use, the
basic RTP specification provides only limited options for media basic RTP specification provides only limited options for media
security, and defines no standard key exchange mechanism. Rather, a security, and defines no standard key exchange mechanism. Rather, a
number of extensions are defined that can provide confidentiality and number of extensions are defined that can provide confidentiality and
authentication of RTP media streams and RTP Control Protocol (RTCP) authentication of RTP media streams and RTP Control Protocol (RTCP)
messages. Other mechanisms define key exchange protocols. This memo messages. Other mechanisms define key exchange protocols. This memo
outlines why it is appropriate that multiple extension mechanisms are outlines why it is appropriate that multiple extension mechanisms are
defined rather than mandating a single security and keying mechanism. defined rather than mandating a single security and keying mechanism
for all users of RTP.
The IETF policy on Strong Security Requirements for IETF Standard The IETF policy on Strong Security Requirements for IETF Standard
Protocols [RFC3365] (the so-called "Danvers Doctrine") states that Protocols [RFC3365] (the so-called "Danvers Doctrine") states that
"we MUST implement strong security in all protocols to provide for "we MUST implement strong security in all protocols to provide for
the all too frequent day when the protocol comes into widespread use the all too frequent day when the protocol comes into widespread use
in the global Internet". The mechanisms defined for use with RTP in the global Internet". The security mechanisms defined for use
allow these requirements to be met. However, since RTP is a protocol with RTP allow these requirements to be met. However, since RTP is a
framework that is suitable for a wide variety of use cases, there is protocol framework that is suitable for a wide variety of use cases,
no single security mechanism that is suitable for every scenario. there is no single security mechanism that is suitable for every
This memo outlines why this is the case, and discusses how users of scenario. This memo outlines why this is the case, and discusses how
RTP can meet the requirement for strong security. users of RTP can meet the requirement for strong security.
This memo provides information for the community and for reviewers of This memo provides information for the community and for reviewers of
future RTP-related work in the IETF. It does not specify a standard future RTP-related work in the IETF. It does not specify a standard
of any kind. of any kind.
2. RTP Applications and Deployment Scenarios 2. RTP Applications and Deployment Scenarios
The range of application and deployment scenarios where RTP has been The range of application and deployment scenarios where RTP has been
used includes, but is not limited to, the following: used includes, but is not limited to, the following:
o Point-to-point voice telephony (fixed and wireless networks) o Point-to-point voice telephony;
o Point-to-point voice and video conferencing o Point-to-point video conferencing and telepresence
o Centralised group video conferencing with a multipoint conference o Centralised group video conferencing and telepresence, using a
unit (MCU) multipoint conference unit (MCU) or similar central middlebox
o Any Source Multicast video conferencing (light-weight sessions; o Any Source Multicast video (ASM) conferencing using the light-
Mbone conferencing) weight sessions model (e.g., the Mbone conferencing tools)
o Point-to-point streaming audio and/or video o Point-to-point streaming audio and/or video (e.g., on-demand TV or
movie streaming)
o Source-specific multicast (SSM) streaming to large group (IPTV and o Source-specific multicast (SSM) streaming to large receiver groups
3GPP Multimedia Broadcast Multicast Service (MBMS) [MBMS]) (e.g., IPTV streaming by residential ISPs, or the 3GPP Multimedia
o Replicated unicast streaming to a group Broadcast Multicast Service [MBMS])
o Replicated unicast streaming to a group of receivers
o Interconnecting components in music production studios and video o Interconnecting components in music production studios and video
editing suites editing suites
o Interconnecting components of distributed simulation systems o Interconnecting components of distributed simulation systems
o Streaming real-time sensor data (e.g., e-VLBI radio astronomy) o Streaming real-time sensor data (e.g., e-VLBI radio astronomy)
As can be seen, these scenarios vary from point-to-point to large As can be seen, these scenarios vary from point-to-point sessions to
multicast groups, from interactive to non-interactive, and from low very large multicast groups, from interactive to non-interactive, and
bandwidth (kilobits per second) telephony to high bandwidth (multiple from low bandwidth (kilobits per second) telephony to high bandwidth
gigabits per second) video and data streaming. While most of these (multiple gigabits per second) video and data streaming. While most
applications run over UDP [RFC0768], some use TCP [RFC0793], of these applications run over UDP [RFC0768], some use TCP [RFC0793],
[RFC4614] or DCCP [RFC4340] as their underlying transport. Some run [RFC4614] or DCCP [RFC4340] as their underlying transport. Some run
on highly reliable optical networks, others use low rate unreliable on highly reliable optical networks, others use low rate unreliable
wireless networks. Some applications of RTP operate entirely within wireless networks. Some applications of RTP operate entirely within
a single trust domain, others are inter-domain, with untrusted (and a single trust domain, others run inter-domain, with untrusted (and,
potentially unknown) users. The range of scenarios is wide, and in some cases, potentially unknown) users. The range of scenarios is
growing both in number and in heterogeneity. wide, and growing both in number and in heterogeneity.
3. RTP Media Security 3. RTP Media Security
The wide range of application scenarios where RTP is used has led to The wide range of application scenarios where RTP is used has led to
the development of multiple solutions for securing RTP media streams the development of multiple solutions for securing RTP media streams
and RTCP control messages, considering different requirements. and RTCP control messages, considering different requirements.
Perhaps the most widely applicable of these security options is the Perhaps the most widely applicable of these security options is the
Secure RTP (SRTP) framework [RFC3711]. This is an application-level Secure RTP (SRTP) framework [RFC3711]. This is an application-level
media security solution, encrypting the media payload data (but not media security solution, encrypting the media payload data (but not
the RTP headers) to provide confidentiality, and supporting source the RTP headers) to provide confidentiality, and supporting source
origin authentication as an option. SRTP was carefully designed to origin authentication as an option. SRTP was carefully designed to
be both low overhead, and to support the group communication and be low overhead, including operating on links subject to RTP header
third-party performance monitoring features of RTP, across a range of compression, and to support the group communication and third-party
networks. performance monitoring features of RTP, across a range of networks.
SRTP is not the only media security solution in use, however, and SRTP is not the only media security solution for RTP, however, and
alternatives are more appropriate for some scenarios, and necessary alternatives can be more appropriate in some scenarios, perhaps due
in some cases where SRTP is not suitable. For example, ISMAcryp to ease of integration with other parts of the complete system. In
[ISMACrypt2] provides payload-level confidentiality that is addition, SRTP does not address all possible security requirements,
appropriate for certain types of streaming video application, but and other solutions are needed in cases where SRTP is not suitable.
that is not suitable for voice telephony (the range of available RTP For example, ISMAcryp payload-level confidentiality [ISMACrypt2] is
security options, and their applicability to different scenarios, is appropriate for some types of streaming video application, but is not
outlined in [I-D.ietf-avtcore-rtp-security-options]). At present, suitable for voice telephony, and uses features that are not provided
there is no media security protocol that is appropriate for all the by SRTP.
environments where RTP is used. Multiple RTP media security
protocols can be expected to remain in wide use for the foreseeable The range of available RTP security options, and their applicability
to different scenarios, is outlined in
[I-D.ietf-avtcore-rtp-security-options]. At the time of this
writing, there is no media security protocol that is appropriate for
all the environments where RTP is used. Multiple RTP media security
protocols are expected to remain in wide use for the foreseeable
future. future.
4. RTP Session Establishment and Key Management 4. RTP Session Establishment and Key Management
A range of different protocols for RTP session establishment and key A range of different protocols for RTP session establishment and key
exchange exist, matching the diverse range of use cases for the RTP exchange exist, matching the diverse range of use cases for the RTP
framework. These mechanisms can be split into two categories: those framework. These mechanisms can be split into two categories: those
that operate in-band on the media path, and those that are out-of- that operate in-band on the media path, and those that are out-of-
band and operate as part of the session establishment signalling band and operate as part of the session establishment signalling
channel. The requirements for these two classes of solution are channel. The requirements for these two classes of solution are
different, and a wide range of solutions have been developed in this different, and a wide range of solutions have been developed in this
space. space.
A more detailed survey of requirements for media security management A more detailed survey of requirements for media security management
protocols can be found in [RFC5479]. As can be seen, the range of protocols can be found in [RFC5479]. As can be seen from that memo,
use cases is wide, and there is no single key management protocol the range of use cases is wide, and there is no single key management
that is appropriate for all scenarios. These solutions have been protocol that is appropriate for all scenarios. The solutions have
further diversified by the existence of infrastructure elements such been further diversified by the existence of infrastructure elements,
as authentication solutions that are tied into the key management. such as authentication systems, that are tied to the key management.
Some of the available keying options for RTP sessions are described The most important and widely used keying options for RTP sessions at
in [I-D.ietf-avtcore-rtp-security-options], although this list is not the time of this writing are described in
ensured to be exhaustive but include the ones known to the authors at [I-D.ietf-avtcore-rtp-security-options].
the time of publication.
5. On the Requirement for Strong Security in Framework protocols 5. On the Requirement for Strong Security in Framework protocols
The IETF requires that all protocols provide a strong, mandatory to The IETF requires that all protocols provide a strong, mandatory to
implement, security solution [RFC3365]. This is essential for the implement, security solution [RFC3365]. This is essential for the
overall security of the Internet, to ensure that all implementations overall security of the Internet, to ensure that all implementations
of a protocol can interoperate in a secure way. Framework protocols of a protocol can interoperate in a secure way. Framework protocols
offer a challenge for this mandate, however, since they are designed offer a challenge for this mandate, however, since they are designed
for use by different classes of applications, in different to be used by different classes of applications, in a wide range of
environments. The different use cases for the framework have different environments. The different use cases for the framework
different security requirements, and implementations designed for have different security requirements, and implementations designed
different environments are generally not expected to interwork. for different environments are generally not expected to interwork.
RTP is an example of a framework protocol with wide applicability. RTP is an example of a framework protocol with wide applicability.
The wide range of scenarios described in Section 2 show the issues The wide range of scenarios described in Section 2 show the issues
that arise in mandating a single security mechanism for this type of that arise in mandating a single security mechanism for this type of
framework. It would be desirable if a single media security framework. It would be desirable if a single media security
solution, and a single key management solution, could be developed, solution, and a single key management solution, could be developed,
suitable for applications across this range of use scenarios. The suitable for applications across this range of use scenarios. The
authors are not aware of any such solution, however, and believe it authors are not aware of any such solution, however, and believe it
is unlikely that any such solution will be developed. In part, this is unlikely that any such solution will be developed. In part, this
is because applications in the different domains are not intended to is because applications in the different domains are not intended to
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RTP is an example of a framework protocol with wide applicability. RTP is an example of a framework protocol with wide applicability.
The wide range of scenarios described in Section 2 show the issues The wide range of scenarios described in Section 2 show the issues
that arise in mandating a single security mechanism for this type of that arise in mandating a single security mechanism for this type of
framework. It would be desirable if a single media security framework. It would be desirable if a single media security
solution, and a single key management solution, could be developed, solution, and a single key management solution, could be developed,
suitable for applications across this range of use scenarios. The suitable for applications across this range of use scenarios. The
authors are not aware of any such solution, however, and believe it authors are not aware of any such solution, however, and believe it
is unlikely that any such solution will be developed. In part, this is unlikely that any such solution will be developed. In part, this
is because applications in the different domains are not intended to is because applications in the different domains are not intended to
interwork, so there is no incentive to develop a single mechanism. interwork, so there is no incentive to develop a single mechanism.
More importantly, though, the security requirements for the different More importantly, though, the security requirements for the different
usage scenarios vary widely, and an appropriate security mechanism in usage scenarios vary widely, and an appropriate security mechanism in
one scenario simply does not work for some other scenarios. one scenario simply does not work for some other scenarios.
For a framework protocol, it appears that the only sensible solution For a framework protocol, it appears that the only sensible solution
to the strong security requirement of [RFC3365] is to develop and use to the strong security requirement of [RFC3365] is to develop and use
building blocks for the basic security services of confidentiality, building blocks for the basic security services of confidentiality,
integrity protection, authorisation, and authentication. When new integrity protection, authorisation, authentication, and so on. When
uses for the framework arise, they need to be studied to check if the new uses for the framework protocol arise, they need to be studied to
existing building blocks satisfy the requirements. A mandatory to determine if the existing security building blocks can satisfy the
implement set of security building blocks can then be specified for requirements, or if new building blocks need to be developed. A
that usage scenario of the framework. mandatory to implement set of security building blocks can then be
specified for that usage scenario of the framework.
Therefore, when considering the strong and mandatory to implement Therefore, when considering the strong and mandatory to implement
security mechanism for a specific class of applications, one has to security mechanism for a specific class of applications, one has to
consider what security building blocks need to be supported. To consider what security building blocks need to be supported. To
maximize interoperability it is important that common media security maximize interoperability it is important that common media security
and key management mechanisms are defined for classes of application and key management mechanisms are defined for classes of application
with similar requirements. The IETF needs to participate in this with similar requirements. The IETF needs to participate in this
selection of security building blocks for each class of applications selection of security building blocks for each class of applications
that use the protocol framework and are expected to interoperate that use the protocol framework and are expected to interoperate, in
where IETF has the appropriate knowledge of the class of cases where the IETF has the appropriate knowledge of the class of
applications. applications.
6. Guidelines for Securing the RTP Protocol Framework 6. Guidelines for Securing the RTP Protocol Framework
The IETF requires that protocols specify mandatory to implement (MTI) The IETF requires that protocols specify mandatory to implement (MTI)
strong security [RFC3365]. This applies to the specification of each strong security [RFC3365]. This applies to the specification of each
interoperable class of application that makes use of RTP. However, interoperable class of application that makes use of RTP. However,
RTP is a framework protocol, so the arguments made in Section 5 also RTP is a framework protocol, so the arguments made in Section 5 also
apply. Given the variability of the classes of application that use apply. Given the variability of the classes of application that use
RTP, and the variety of the currently available security mechanisms RTP, and the variety of the currently available security mechanisms
described in [I-D.ietf-avtcore-rtp-security-options], no one set of described in [I-D.ietf-avtcore-rtp-security-options], no one set of
MTI security options can realistically be specified that apply to all MTI security options can realistically be specified that apply to all
classes of RTP applications. classes of RTP applications.
Documents that define an interoperable class of applications using Documents that define an interoperable class of applications using
RTP are subject to [RFC3365] and need to specify MTI security RTP are subject to [RFC3365], and so need to specify MTI security
mechanisms. This is because such specifications do fully specify mechanisms. This is because such specifications do fully specify
interoperable applications that use RTP. Examples of such a interoperable applications that use RTP. Examples of such documents
documents in development at the time of this writing would be the under development in the IETF at the time of this writing are the
RTCWEB Security Architecture [I-D.ietf-rtcweb-security-arch] and Real RTCWEB Security Architecture [I-D.ietf-rtcweb-security-arch] and the
Time Streaming Protocol 2.0 (RTSP) [I-D.ietf-mmusic-rfc2326bis]. It Real Time Streaming Protocol 2.0 (RTSP) [I-D.ietf-mmusic-rfc2326bis].
is also expected that a similar document will be produced for voice- It is also expected that a similar document will be produced for
over-IP applications using SIP and RTP. voice-over-IP applications using SIP and RTP.
The RTP framework can be extended in ways that do not specify an The RTP framework includes several extension points. Some extensions
interoperable class of applications. Two important extension points can significantly change the behaviour of the protocol, to the extent
are RTP Payload Formats and RTP Profiles. An RTP Payload Format that applications using the extension form a separate interoperable
defines how the output of a media codec can be used with RTP. At the class of applications to those that have not been extended. Other
time of this writing, there are over 70 RTP Payload Formats defined extension points are defined in such a manner that they can be used
in published RFCs, with more in development. It is appropriate for (largely) independently of the class of applications using RTP. Two
an RTP payload format to discuss specific security implications of important extension points that are can be independent of the class
using that codec with RTP. However, an RTP payload format does not of applications are RTP Payload Formats and RTP Profiles.
specify an interoperable class of applications that use RTP, and is
neither secure in itself, nor something to which [RFC3365] applies. An RTP Payload Format defines how the output of a media codec can be
Future RTP payload format specifications ought to explicitly state used with RTP. At the time of this writing, there are over 70 RTP
this, and include a reference to this memo for explanation. It is Payload Formats defined in published RFCs, with more in development.
not appropriate for an RTP payload format to mandate the use of SRTP It is appropriate for an RTP payload format to discuss the specific
[RFC3711], or any other security building blocks, since that RTP security implications of using that media codec with RTP. However,
an RTP payload format does not specify an interoperable class of
applications that use RTP since, in the vast majority of cases, a
media codec and it's associated RTP payload format can be used with
many different classes of application. As such, an RTP payload
format is neither secure in itself, nor something to which [RFC3365]
applies. Future RTP payload format specifications need to explicitly
state this, and include a reference to this memo for explanation. It
is not appropriate for an RTP payload format to mandate the use of
SRTP [RFC3711], or any other security building blocks, since that RTP
payload format might be used by different classes of application that payload format might be used by different classes of application that
use RTP, and that have different security requirements. use RTP, and that have different security requirements.
RTP profiles are larger extensions that adapt the RTP framework for RTP profiles are larger extensions that adapt the RTP framework for
use with particular classes of application. In some cases, those use with particular classes of application. In some cases, those
classes of application might share common security requirements so classes of application might share common security requirements so
that it could make sense for an RTP profile to mandate particular that it could make sense for an RTP profile to mandate particular
security options and building blocks (the RTP/SAVP profile [RFC3711] security options and building blocks (the RTP/SAVP profile [RFC3711]
is an example of this type of RTP profile). In other cases, though, is an example of this type of RTP profile). In other cases, though,
an RTP profile is applicable to such a wide range of applications an RTP profile is applicable to such a wide range of applications
that it would not make sense for that profile to mandate particular that it would not make sense for that profile to mandate particular
security building blocks be used (the RTP/AVPF profile [RFC4585] is security building blocks be used (the RTP/AVPF profile [RFC4585] is
an example of this type of RTP profile, since it provides building an example of this type of RTP profile, since it provides building
blocks that can be used in different styles of application). Any new blocks that can be used in different styles of application). A new
RTP profile needs to discuss if it makes sense to mandate particular RTP profile specification needs to discuss whether, or not, it makes
security building blocks be used with implementations of that sense to mandate particular security building blocks that need to be
profile, but without the expectation that all RTP profiles will used with all implementations of that profile; however, there is no
mandate particular security solutions. RTP profiles that do not expectation that all RTP profiles will mandate particular security
specify an interoperable usage for a particular class of RTP solutions. RTP profiles that do not specify an interoperable usage
applications are neither secure in themselves, nor something to which for a particular class of RTP applications are neither secure in
[RFC3365] applies; any future RTP profiles in this category need to themselves, nor something to which [RFC3365] applies; any future RTP
explicitly state this with justification, and include a reference to profiles in this category need to explicitly state this with
this memo. justification, and include a reference to this memo.
7. Conclusions 7. Conclusions
The RTP framework is used in a wide range of different scenarios, The RTP framework is used in a wide range of different scenarios,
with no common security requirements. Accordingly, neither SRTP with no common security requirements. Accordingly, neither SRTP
[RFC3711], nor any other single media security solution or keying [RFC3711], nor any other single media security solution or keying
mechanism, can be mandated for all uses of RTP. In the absence of a mechanism, can be mandated for all uses of RTP. In the absence of a
single common security solution, it is important to consider what single common security solution, it is important to consider what
mechanisms can be used to provide strong and interoperable security mechanisms can be used to provide strong and interoperable security
for each different scenario where RTP applications are used. This for each different scenario where RTP applications are used. This
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10. Acknowledgements 10. Acknowledgements
Thanks to Ralph Blom, Hannes Tschofenig, Dan York, Alfred Hoenes, Thanks to Ralph Blom, Hannes Tschofenig, Dan York, Alfred Hoenes,
Martin Ellis, Ali Begen, Keith Drage, Ray van Brandenburg, Stephen Martin Ellis, Ali Begen, Keith Drage, Ray van Brandenburg, Stephen
Farrell, and Sean Turner for their feedback. Farrell, and Sean Turner for their feedback.
11. Informative References 11. Informative References
[I-D.ietf-avtcore-rtp-security-options] [I-D.ietf-avtcore-rtp-security-options]
Westerlund, M. and C. Perkins, "Options for Securing RTP Westerlund, M. and C. Perkins, "Options for Securing RTP
Sessions", draft-ietf-avtcore-rtp-security-options-02 Sessions", draft-ietf-avtcore-rtp-security-options-03
(work in progress), February 2013. (work in progress), May 2013.
[I-D.ietf-mmusic-rfc2326bis] [I-D.ietf-mmusic-rfc2326bis]
Schulzrinne, H., Rao, A., Lanphier, R., Westerlund, M., Schulzrinne, H., Rao, A., Lanphier, R., Westerlund, M.,
and M. Stiemerling, "Real Time Streaming Protocol 2.0 and M. Stiemerling, "Real Time Streaming Protocol 2.0
(RTSP)", draft-ietf-mmusic-rfc2326bis-31 (work in (RTSP)", draft-ietf-mmusic-rfc2326bis-34 (work in
progress), February 2013. progress), April 2013.
[I-D.ietf-rtcweb-security-arch] [I-D.ietf-rtcweb-security-arch]
Rescorla, E., "RTCWEB Security Architecture", Rescorla, E., "RTCWEB Security Architecture", draft-ietf-
draft-ietf-rtcweb-security-arch-06 (work in progress), rtcweb-security-arch-06 (work in progress), January 2013.
January 2013.
[ISMACrypt2] [ISMACrypt2]
"ISMA Encryption and Authentication, Version 2.0 release Internet Streaming Media Alliance (ISMA), , "ISMA
Encryption and Authentication, Version 2.0 release
version", November 2007. version", November 2007.
[MBMS] 3GPP, "Multimedia Broadcast/Multicast Service (MBMS); [MBMS] 3GPP, , "Multimedia Broadcast/Multicast Service (MBMS);
Protocols and codecs TS 26.346". Protocols and codecs TS 26.346", .
[RFC0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768, [RFC0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768,
August 1980. August 1980.
[RFC0793] Postel, J., "Transmission Control Protocol", STD 7, [RFC0793] Postel, J., "Transmission Control Protocol", STD 7, RFC
RFC 793, September 1981. 793, September 1981.
[RFC3365] Schiller, J., "Strong Security Requirements for Internet [RFC3365] Schiller, J., "Strong Security Requirements for Internet
Engineering Task Force Standard Protocols", BCP 61, Engineering Task Force Standard Protocols", BCP 61, RFC
RFC 3365, August 2002. 3365, August 2002.
[RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V. [RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V.
Jacobson, "RTP: A Transport Protocol for Real-Time Jacobson, "RTP: A Transport Protocol for Real-Time
Applications", STD 64, RFC 3550, July 2003. Applications", STD 64, RFC 3550, July 2003.
[RFC3711] Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K. [RFC3711] Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K.
Norrman, "The Secure Real-time Transport Protocol (SRTP)", Norrman, "The Secure Real-time Transport Protocol (SRTP)",
RFC 3711, March 2004. RFC 3711, March 2004.
[RFC4340] Kohler, E., Handley, M., and S. Floyd, "Datagram [RFC4340] Kohler, E., Handley, M., and S. Floyd, "Datagram
Congestion Control Protocol (DCCP)", RFC 4340, March 2006. Congestion Control Protocol (DCCP)", RFC 4340, March 2006.
[RFC4585] Ott, J., Wenger, S., Sato, N., Burmeister, C., and J. Rey, [RFC4585] Ott, J., Wenger, S., Sato, N., Burmeister, C., and J. Rey,
"Extended RTP Profile for Real-time Transport Control "Extended RTP Profile for Real-time Transport Control
Protocol (RTCP)-Based Feedback (RTP/AVPF)", RFC 4585, Protocol (RTCP)-Based Feedback (RTP/AVPF)", RFC 4585, July
July 2006. 2006.
[RFC4614] Duke, M., Braden, R., Eddy, W., and E. Blanton, "A Roadmap [RFC4614] Duke, M., Braden, R., Eddy, W., and E. Blanton, "A Roadmap
for Transmission Control Protocol (TCP) Specification for Transmission Control Protocol (TCP) Specification
Documents", RFC 4614, September 2006. Documents", RFC 4614, September 2006.
[RFC5479] Wing, D., Fries, S., Tschofenig, H., and F. Audet, [RFC5479] Wing, D., Fries, S., Tschofenig, H., and F. Audet,
"Requirements and Analysis of Media Security Management "Requirements and Analysis of Media Security Management
Protocols", RFC 5479, April 2009. Protocols", RFC 5479, April 2009.
Authors' Addresses Authors' Addresses
 End of changes. 35 change blocks. 
126 lines changed or deleted 142 lines changed or added

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