One document matched: draft-ietf-mmusic-sdp-mux-attributes-03.xml
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<rfc category="std" docName="draft-ietf-mmusic-sdp-mux-attributes-03"
ipr="pre5378Trust200902">
<front>
<title abbrev="SDP Attribute Multiplexing">A Framework for SDP Attributes
when Multiplexing</title>
<author fullname="Suhas Nandakumar" initials="S." surname="Nandakumar">
<organization>Cisco</organization>
<address>
<postal>
<street>170 West Tasman Drive</street>
<city>San Jose</city>
<region>CA</region>
<code>95134</code>
<country>USA</country>
</postal>
<email>snandaku@cisco.com</email>
</address>
</author>
<date day="20" month="October" year="2014" />
<area>MMUSIC</area>
<abstract>
<t>
The Session Description Protocol (SDP) provides mechanisms to
describe attributes of multimedia sessions and of individual
media streams (e.g., Real-time Transport Protocol (RTP)
sessions) within a multimedia session. In the RTCWeb WG, there
is a need to use a single 5-tuple for sending and receiving
media associated with multiple media descriptions ("m="
lines). Such a requirement has raised concerns over the
semantic implications of the SDP attributes associated with
the RTP Media Streams multiplexed over a single transport
layer flow.
</t>
<t>
The scope of this specification is to provide a framework for
analyzing the multiplexing characteristics of SDP
attributes. The specification also categorizes existing
attributes based on the framework described herein.
</t>
</abstract>
</front>
<middle>
<section title="Introduction">
<t>
Real-Time Communication Web (RTCWeb) framework requires
Real-time Transport Protocol (RTP) as the media transport
protocol and Session Description Protocol (SDP) <xref
target="RFC4566"/> for describing and negotiating multi-media
communication sessions.
</t>
<t>
SDP defines several attributes for capturing characteristics
that apply to the individual media descriptions (described by
"m=" lines") and the overall multimedia session. Typically
different media types (audio, video etc) described using
different media descriptions represent separate RTP Sessions
that are carried over individual transport layer flows.
However in the IETF RTCWEB WG, a need to use a single 5-tuple
for sending and receiving media associated with multiple SDP
media descriptions ("m=" lines) has been identified. This
would e.g. allow the usage of a single set of Interactive
Connectivity Establishment (ICE) [RFC5245] candidates for
multiple media descriptions. This in turn has made necessary
to understand the interpretation and usage of the SDP
attributes defined for the multiplexed media descriptions.
</t>
<t>
Given the number of SDP attributes registered with the IANA
<xref target="IANA"></xref> and possibility of new attributes
being defined in the future, there is need for generic
future-proof framework to analyze these attributes for their
applicability in the transport multiplexing use-cases.
</t>
<t>
The document starts with providing the motivation for
requiring such a framework. This is followed by introduction
to the SDP attribute analysis framework/procedures, following
which several sections applies the framework to the SDP
attributes registered with the IANA <xref
target="IANA"></xref>
</t>
</section>
<section title="Terminology">
<t>The key words "MUST", "MUST NOT", "REQUIRED", "SHOULD",
"SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in <xref
target="RFC2119"></xref>.</t>
</section>
<section title="Motivation">
<t>
The time and complications of setting up ICE <xref
target="RFC5245"></xref> and DTLS-SRTP <xref
target="RFC5763"></xref> transports for use by RTP, and
conservation of ports, forms an requirement to try and reduce
the number of transport level flows needed. This has resulted
in the definition of ways, such as, <xref
target="I-D.ietf-mmusic-sdp-bundle-negotiation"></xref> to
multiplex RTP over a single transport flow in order to
preserve network resources such as port numbers. This imposes
further restrictions on applicability of these SDP attributes
as they are defined today.
</t>
<t>
The specific problem is that there are attribute combinations
which make sense when specified on independent m-lines -- as
with classical SDP -- that do not make sense when those
m-lines are then multiplexed over the same transport. To give
an obvious example, ICE permits each m=line to have an
independently specified ice-ufrag attribute. However, if the
media from multiple m-lines is multiplexed over the same ICE
component, then the meaning of media-level ice-ufrag
attributes becomes muddled.
</t>
<t>
As of today there are close to 250 SDP attributes registered
with the IANA <xref target="IANA"></xref> and more will be
added in the future. There is no clearly defined procedure to
establish the validity/applicability of these attribute when
used with transport multiplexing.
</t>
</section>
<section title="SDP Attribute Analysis Framework" anchor="sec-mux-cat">
<t>
Attributes in an SDP session description can be defined at the
session-level and media-level. These attributes could be
semantically grouped as noted below.
</t>
<t>
<list style="symbols">
<t> Attributes related to media content such as media type,
encoding schemes, payload types.</t>
<t> Attributes specifying media transport characteristics like RTP/RTCP
port numbers, network addresses, QOS.</t>
<t> Metadata description attributes capturing session timing and origin
information.</t>
<t> Attributes establishing relationships between media streams such as
grouping framework</t>
</list>
</t>
<t>
With the above semantic grouping as the reference, the proposed
framework classifies each attribute into one of the following
categories:
</t>
<section title="Category: NORMAL">
<t>Attributes that can be independently specified when
multiplexing and retain their original semantics.</t>
<t> </t>
<t>
In the example given below, the direction and label
attributes are independently specified for audio and video
m=lines. These attributes are not impacted by multiplexing
these media streams over a single transport layer flow.
</t>
<figure>
<artwork align="left" alt="" height="" name="" type="" width=""
xml:space="preserve"><![CDATA[
v=0
o=alice 2890844526 2890844527 IN IP4 host.atlanta.example.com
s=
c=IN IP4 host.atlanta.example.com
t=0 0
m=audio 49172 RTP/AVP 99
a=sendonly
a=label:1
a=rtpmap:99 iLBC/8000
m=video 49172 RTP/AVP 31
a=recvonly
a=label:2
a=rtpmap:31 H261/90000
]]></artwork>
</figure>
<t> </t>
</section>
<section title="Category: NOT RECOMMENDED">
<t>
Attributes that are recommended against multiplexing since
their usage under multiplexing might lead to incorrect
behavior.
</t>
<t> </t>
<t>
Example: Multiplexing media descriptions having attribute
zrtp-hash defined with the media descriptions lacking it,
would either complicate the handling of multiplexed streams
or might fail multiplexing altogether.
</t>
<figure>
<artwork align="left" alt="" height="" name="" type="" width=""
xml:space="preserve"><![CDATA[
v=0
o=bob 2890844527 2890844527 IN IP4 client.biloxi.example.com
s=
c=IN IP4 client.biloxi.example.com
t=0 0
m=audio 3456 RTP/AVP 97 // with zrtp
a=rtpmap:97 iLBC/8000
<allOneLine>
a=zrtp-hash:1.10 fe30efd02423cb054e50efd0248742ac7a52c8f91bc2
df881ae642c371ba46df
</allOneLine>
m=video 34567 RTP/AVP 31 //without zrtp
a=rtpmap:31 H261/90000
]]></artwork>
</figure>
<t> </t>
</section>
<section title="Category: IDENTICAL">
<t>Attributes that MUST be identical across all the media
descriptions being multiplexed.</t>
<t> </t>
<t>
Attributes such as rtcp-mux fall into this category. Since
RTCP reporting is done per RTP Session, RTCP Multiplexing
MUST to enabled for both the audio and video m=lines in the
example below if they are transported over a single 5-tuple.
</t>
<figure>
<artwork align="left" alt="" height="" name="" type="" width=""
xml:space="preserve"><![CDATA[
v=0
o=bob 2890844527 2890844527 IN IP4 client.biloxi.example.com
s=
c=IN IP4 client.biloxi.example.com
t=0 0
m=audio 34567 RTP/AVP 97
a=rtcp-mux
m=video 34567 RTP/AVP 31
a=rtpmap:31 H261/90000
a=rtcp-mux
]]></artwork>
</figure>
<t> </t>
</section>
<section title="Category: SUM">
<t>Attributes can be set as they are normally used but
software using them in a multiplex case, MUST apply the sum
of all the attributes being multiplexed instead of trying to
use each one. This is typically used for bandwidth or other
rate limiting attributes to the underlining transport. </t>
<t> </t>
<t>
The software parsing the SDP sample below, should use the
aggregate Application Specific (AS) bandwidth value from the
individual media descriptions to determine the AS value for
the multiplexed session. Thus the calculated AS value would
be 256+64 bytes for the given example.
</t>
<figure>
<artwork align="left" alt="" height="" name="" type="" width=""
xml:space="preserve"><![CDATA[
v=0
o=test 2890844526 2890842807 IN IP4 126.16.64.4
c=IN IP4 client.biloxi.example.com
t=0 0
m=audio 49170 RTP/AVP 0
b=AS:64
m=video 51372 RTP/AVP 31
b=AS:256
]]></artwork>
</figure>
<t> </t>
</section>
<section title="Category: TRANSPORT">
<t> Attributes that can be set normally for multiple items in
a multiplexed group but the software MUST pick just one of
the attribute of the given type for use. The one chosen is
the attribute associated with the "m=" line that represents
the information being used for the transport of the RTP.</t>
<t> </t>
<t>
In the example below, "a=crypto" attribute is defined for both
the audio and the video m=lines. The video media line's a=crypto
attribute is chosen since its mid value (bar) appears first in
the a=group:BUNDLE line. This is due to BUNDLE grouping semantic
<xref target="I-D.ietf-mmusic-sdp-bundle-negotiation"></xref>
which mandates the values from m=line corresponding to the mid
appearing first on the a=group:BUNDLE line to be considered for
setting up the RTP Transport.
</t>
<figure>
<artwork align="left" alt="" height="" name="" type="" width=""
xml:space="preserve"><![CDATA[
v=0
o=alice 2890844526 2890844527 IN IP4 host.atlanta.example.com
s=
c=IN IP4 host.atlanta.example.com
t=0 0
a=group:BUNDLE bar foo
m=audio 49172 RTP/AVP 99
a=mid:foo
a=crypto:1 AES_CM_128_HMAC_SHA1_80
inline:d0RmdmcmVCspeEc3QGZiNWpVLFJhQX1cfHAwJSoj|2^20|1:32
a=rtpmap:99 iLBC/8000
m=video 51374 RTP/AVP 31
a=mid:bar
a=crypto:1 AES_CM_128_HMAC_SHA1_80
inline:EcGZiNWpFJhQXdspcl1ekcmVCNWpVLcfHAwJSoj|2^20|1:32
a=rtpmap:96 H261/90000
]]></artwork>
</figure>
<t> </t>
</section>
<section title="Category: INHERIT">
<t> Attributes that encapsulate other SDP attributes or parameters.
These attributes inherit their multiplexing characteristics from the
attributes or parameters they encapsulate. Such attributes as of today,
are defined in [RFC3407], [RFC5939] and [RFC6871] as part of a generic
framework for indicating and negotiating transport, media and
media format related capabilities in the SDP. </t>
<t> The inheritance manifests itself when the encapsulated attribute or
parameter is being leveraged. In the case of SDP Capability Negotiation
[RFC5939] for example, this occurs when a capability (encapsulating attribute)
is used as part of a configuration; the configuration inherits the multiplexing
Category of each of its constituent (encapsulated) attributes and parameters.
This in turn may place constraints on what constitutes a valid configuartion
from a multiplexing point of view, e.g. because some attributes must be
IDENTICAL (see Section 15 for further details).</t>
<t> </t>
<figure>
<artwork align="left" alt="" height="" name="" type="" width=""
xml:space="preserve"><![CDATA[
v=0
o=alice 2890844526 2890844527 IN IP4 host.atlanta.example.com
s=
c=IN IP4 host.atlanta.example.com
t=0 0
m=video 3456 RTP/AVP 100
a=rtpmap:100 VP8/90000
a=fmtp:100 max-fr=30;max-fs=8040
a=sqn: 0
a=cdsc: 1 video RTP/AVP 100
a=cpar: a=rtcp-mux
m=video 3456 RTP/AVP 101
a=rtpmap:101 VP8/90000
a=fmtp:100 max-fr=15;max-fs=1200
a=cdsc: 2 video RTP/AVP 101
a=cpar: a=rtcp-mux
]]></artwork>
</figure>
<t>
In the above example , the category IDENTICAL is inherited for
the cpar encapsulated rtcp-mux attribute.
</t>
<t> </t>
</section>
<section title="Category: IDENTICAL-PER-PT">
<t> Attributes that define the RTP payload configuration on per
Payload Type basis and MUST have identical values across all the
media descriptions for a given RTP Payload Type when
repeated.</t>
<t> </t>
<t>
In the SDP example below, Payload Types 96 and 97 are repeated
across all the video m= lines and all the payload specific
parameters (ex: rtpmap, fmtp) are identical.
</t>
<figure>
<artwork align="left" alt="" height="" name="" type="" width=""
xml:space="preserve"><![CDATA[
v=0
o=alice 2890844526 2890844527 IN IP4 host.atlanta.example.com
s=
c=IN IP4 host.atlanta.example.com
t=0 0
a=group:BUNDLE cam1, cam2
m = video 96 97
a=mid:cam1
a=rtpmap:96 H264/90000
a=fmtp:96 profile-level-id=42400d; max-fs=3600; max-fps=3000;
max-mbps=108000; max-br=1000
a=rtpmap:97 H264/90000
a=fmtp:97 profile-level-id=42400a; max-fs=240; max-fps=3000;
max-mbps=7200; max-br=200
m = video 96 97
a=mid:cam2
a=rtpmap:96 H264/90000
a=fmtp:96 profile-level-id=42400d; max-fs=3600; max-fps=3000;
max-mbps=108000; max-br=1000
a=rtpmap:97 H264/90000
a=fmtp:97 profile-level-id=42400a; max-fs=240; max-fps=3000;
max-mbps=7200; max-br=200
]]>
</artwork>
</figure>
<t> </t>
</section>
<section title="Category: SPECIAL">
<t> Attributes where the text in the source draft must be
consulted for further handling when multiplexed. </t>
<t> As an example, for the attribute extmap, the specification
defining the extension MUST be referred to understand the
multiplexing implications.
</t>
</section>
<section title="Category: TBD">
<t> Attributes that have not been analyzed under the proposed multiplexing
framework yet.
</t>
</section>
</section>
<section title="Analysis of Existing Attributes" anchor="SecCurrAnalysis" >
<t>
This section analyzes attributes listed in <xref
target="IANA">IANA</xref> grouped under the IETF document that
defines them. The "Level" column indicates whether the attribute
is currently specified as:
</t>
<t>
<list style="symbols">
<t>S -- Session level</t>
<t>M -- Media level</t>
<t>B -- Both</t>
<t>SR -- Source-level (for a single SSRC)</t>
</list>
</t>
<section title="RFC4566 - SDP: Session Description Protocol">
<t>
<xref target="RFC4566"/> defines the Session
Description Protocol (SDP) that is intended for describing
multimedia sessions for the purposes of session announcement,
session invitation, and other forms of multimedia session
initiation
</t>
<texttable title="RFC4566 Attribute Analysis">
<ttcol align='left'>Attr Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>sendrecv </c><c>Not impacted </c><c>B </c>
<c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>sendonly </c><c>Not impacted </c><c>B </c>
<c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>recvonly </c><c>Not impacted </c><c>B </c>
<c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>inactive </c><c>Not impacted </c><c>B </c>
<c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>cat </c><c>Not impacted </c><c>S </c>
<c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>ptime </c><c> The attribute value must be same
for a given codec configuration </c>
<c>M </c><c>IDENTICAL-PER-PT</c>
<c> </c><c> </c><c> </c><c> </c>
<c>maxptime </c><c>The attribute value must be same
for a given codec configuration </c>
<c>M </c><c>IDENTICAL-PER-PT</c>
<c> </c><c> </c><c> </c><c> </c>
<c>orient </c><c>Not Impacted
</c><c>M </c><c>NORMAL</c>
<c> </c><c> </c><c> </c><c> </c>
<c>framerate </c><c>The attribute value must be same
for a given codec configuration </c><c>M </c>
<c>IDENTICAL-PER-PT </c>
<c> </c><c> </c><c> </c><c> </c>
<c>quality </c><c>Not Impacted
</c><c>M </c><c>NORMAL</c>
<c> </c><c> </c><c> </c><c> </c>
<c>rtpmap </c><c>The attribute value must be same
for a given codec configuration </c><c>M </c>
<c>IDENTICAL-PER-PT</c>
<c> </c><c> </c><c> </c><c> </c>
<c>fmtp </c><c>The attribute value must be same
for a given codec configuration </c><c>M </c>
<c>IDENTICAL-PER-PT</c>
<c> </c><c> </c><c> </c><c> </c>
<c>keywds </c><c>Not impacted </c><c>S </c>
<c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>type </c><c>Not Impacted
</c><c>S </c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>type:broadcast </c><c>Not Impacted
</c><c>S </c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>type:H332 </c><c>Not Impacted
</c><c>S </c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>type:meeting </c><c>Not Impacted
</c><c>S </c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>type:moderated </c><c>Not Impacted
</c><c>S </c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>type:test </c><c>Not Impacted
</c><c>S </c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>tool </c><c>Not Impacted
</c><c>S </c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>charset </c><c>Not Impacted
</c><c>S </c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>sdplang </c><c>Not Impacted
</c><c>B </c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>lang </c><c>Not Impacted
</c><c>B </c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC4585 - RTP/AVPF">
<t>
<xref target="RFC4585"/> defines an extension to
the Audio-visual Profile (AVP) that enables receivers to
provide, statistically, more immediate feedback to the senders
and thus allows for short-term adaptation and efficient
feedback-based repair mechanisms to be implemented.
</t>
<texttable title="RFC4585 Attribute Analysis">
<ttcol align='left'>Attr Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>rtcp-fb </c><c>Since RTCP feedback attributes are Payload Type
(PT) scoped, their values MUST be identical for a given PT across
the multiplexed m=lines.</c><c>M</c><c>IDENTICAL-PER-PT </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC5761 - Multiplexing RTP and RTCP">
<t>
<xref target="RFC5761"/> discusses issues that
arise when multiplexing RTP data packets and RTP Control
Protocol (RTCP) packets on a single UDP port. It describes
when such multiplexing is and is not appropriate, and it
explains how the Session Description Protocol (SDP) can be
used to signal multiplexed sessions.
</t>
<texttable title="RFC5761 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>rtcp-mux </c><c>RTP and RTCP Multiplexing affects the
entire RTP Session </c>
<c>M </c><c>IDENTICAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC3312 - Integration of Resource Management and (SIP)">
<t>
<xref target="RFC3312"/> defines a generic framework for
preconditions, which are extensible through IANA registration.
This document also discusses how network quality of service can be
made a precondition for establishment of sessions initiated by the
Session Initiation Protocol (SIP). These preconditions require that
the participant reserve network resources before continuing with the
session.
</t>
<texttable title="RFC3312 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>des </c><c>Refer to notes below </c>
<c>M </c><c>NOT RECOMMEDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>conf </c><c>Refer to notes below </c>
<c>M </c><c>NOT RECOMMEDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>curr </c><c>Refer to notes below </c>
<c>M </c><c>NOT RECOMMEDED </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
<t hangText="Note">
A mismatched set of Preconditions across media descriptions
results in Session establishment failures due to inability
to meet the right resource reservations requested.
</t>
</section>
<section title="RFC4574 - SDP Label Attribute ">
<t>
<xref target="RFC4574"/> defines a new Session
Description Protocol (SDP) media-level attribute: "label".
The "label" attribute carries a pointer to a media stream in
the context of an arbitrary network application that uses
SDP. The sender of the SDP document can attach the "label"
attribute to a particular media stream or streams. The
application can then use the provided pointer to refer to
each particular media stream in its context.
</t>
<texttable title="RFC4574 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>label </c><c>Not Impacted </c><c>M</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC5432 - QoS Mechanism Selection in SDP">
<t>
<xref target="RFC5432"/> defines procedures to
negotiate QOS mechanisms using the Session Description
Protocol (SDP) offer/answer model.
</t>
<texttable title="RFC5432 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>qos-mech-send </c>
<c> A single DSCP code point per flow being multiplexed
doesn't impact multiplexing since QOS mechanisms are
signaled/scoped per flow. </c>
<c>B</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>qos-mech-recv </c>
<c>A single DSCP code point per flow being multiplexed
doesn't impact multiplexing since QOS mechanisms are
signaled/scoped per flow. </c>
<c>B</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
<t hangText="Note">
For scenarios that involves having different DSCP for packets
being transmitted over the same 5-tuple, i.e. what is
being in the same bundle, has issues as discussed in
<xref target="I.D-draft-ietf-dart-dscp-rtp"/>
</t>
</section>
<section title="RFC4568 - SDP Security Descriptions">
<t>
<xref target="RFC4568"/> defines a Session
Description Protocol (SDP) cryptographic attribute for
unicast media streams. The attribute describes a
cryptographic key and other parameters that serve to
configure security for a unicast media stream in either a
single message or a roundtrip exchange.
</t>
<texttable title="RFC4568 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>crypto </c><c>crypto attribute must be the one that corresponds
to the m=line chosen for setting up the underlying transport flow </c>
<c>M </c><c>TRANSPORT </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC5762 - RTP over DCCP">
<t>
The Real-time Transport Protocol (RTP) is a widely used
transport for real-time multimedia on IP networks. The
Datagram Congestion Control Protocol (DCCP) is a transport
protocol that provides desirable services for real-time
applications. <xref target="RFC5762"/>
specifies a mapping of RTP onto DCCP, along with associated
signaling, such that real-time applications can make use of
the services provided by DCCP
</t>
<texttable title="RFC5762 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Current</ttcol>
<ttcol align='left'>Category</ttcol>
<c>dccp-service-code </c><c> If RFC6773 is not being
used in addition to RFC5762, the port in the m= line is a
DCCP port. DCCP being a connection oriented protocol, does
not allow multiple connections on the same
5-tuple. </c> <c>M </c><c>NOT
RECOMMENDED </c><c> </c>
<c> </c><c> </c><c> </c>
</texttable>
<t hangText="Note">
If RFC6773 is being used in addition to RFC5762 and provided
that DCCP-in-UDP layer has additional demultiplexing, then it
may be possible to use different DCCP service codes for each
DCCP flow, given each uses a different DCCP port. Although
doing so might conflict with the media type of the m=
line. None of this is standardized yet and it wouldn't work
as explained. Hence multiplexing MUST NOT be performed even
in this alternate scenario.
</t>
</section>
<section title="RFC6773 - DCCP-UDP Encapsulation">
<t>
<xref target="RFC6773"/> document specifies an
alternative encapsulation of the Datagram Congestion Control
Protocol (DCCP), referred to as DCCP-UDP. This
encapsulation allows DCCP to be carried through the current
generation of Network Address Translation (NAT) middle boxes
without modification of those middle boxes
</t>
<texttable title="RFC6773 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>dccp-port </c><c> Multiplexing MUST NOT be performed
due to potential conflict between the port used for DCCP
en/decapsulation and the RTP. </c> <c>M </c><c>NOT
RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
<t hangText="Note">
Since RFC6773 is about tunnelling DCCP in UDP, with the UDP
port being the port of the DCCP en-/de-capsulation
service. This encapsulation allows arbitrary DCCP packets to
be encapsulated and the DCCP port choosen MAY conflict with
the port chosen for the RTP traffic.
</t>
<t>
For multiplexing several DCCP-in-UDP encapsulations on the
same UDP port, with no RTP traffic on the same port implies
collapsing several DCCP port spaces together. This MAY or
MAY NOT work depending on the nature of DCCP encapsulations
and ports choses thus rendering it to be very application
dependant.
</t>
</section>
<section title="RFC5506 - Reduced-Size RTCP in RTP Profile">
<t>
<xref target="RFC5506"/> discusses benefits and
issues that arise when allowing Real-time Transport Protocol
(RTCP) packets to be transmitted with reduced size.
</t>
<texttable title="RFC5506 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>rtcp-rsize </c><c>Reduced size RTCP affects the
entire RTP Session </c>
<c>M </c><c>IDENTICAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC6787 - Media Resource Control Protocol Version 2">
<t>
The Media Resource Control Protocol Version 2 (MRCPv2)
allows client hosts to control media service resources such
as speech synthesizers, recognizers, verifiers, and
identifiers residing in servers on the network. MRCPv2 is
not a "stand-alone" protocol -- it relies on other
protocols, such as the Session Initiation Protocol (SIP), to
coordinate MRCPv2 clients and servers and manage sessions
between them, and the Session Description Protocol (SDP) to
describe, discover, and exchange capabilities. It also
depends on SIP and SDP to establish the media sessions and
associated parameters between the media source or sink and
the media server. Once this is done, the MRCPv2 exchange
operates over the control session established above,
allowing the client to control the media processing
resources on the speech resource server. <xref
target="RFC6787"/> defines attributes for this
purpose.
</t>
<texttable title="RFC6787 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>resource </c><c>Not Impacted </c><c>M </c>
<c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>channel </c><c>Not Impacted </c><c>M </c>
<c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC5245 - Interactive Connectivity Establishment (ICE)">
<t>
<xref target="RFC5245"/> describes a protocol
for Network Address Translator(NAT) traversal for UDP-based
multimedia sessions established with the offer/answer model.
This protocol is called Interactive Connectivity
Establishment (ICE). ICE makes use of the Session Traversal
Utilities for NAT (STUN) protocol and its
extension,Traversal Using Relay NAT (TURN). ICE can be used
by any protocol utilizing the offer/answer model, such as
the Session Initiation Protocol (SIP).
</t>
<texttable title="RFC5245 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>ice-lite </c><c>Not Impacted </c>
<c>S</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>ice-options </c><c>Not Impacted </c>
<c>S</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>ice-mismatch </c><c>Not Impacted </c>
<c>S</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>ice-pwd </c><c>ice-pwd MUST be the one that
corresponds to the m=line chosen for setting up the
underlying transport flow </c>
<c>B</c><c>TRANSPORT </c>
<c> </c><c> </c><c> </c><c> </c>
<c>ice-ufrag </c><c>ice-ufrag MUST be the one that
corresponds to the m=line chosen for setting up the
underlying transport flow </c>
<c>B</c><c>TRANSPORT </c>
<c> </c><c> </c><c> </c><c> </c>
<c>candidate </c><c>ice candidate MUST be the one that
corresponds to the m=line chosen for setting up the
underlying transport
flow </c><c>M</c><c>TRANSPORT </c>
<c> </c><c> </c><c> </c><c> </c>
<c>remote-candidates </c><c>ice remote candidate MUST
be the one that corresponds to the m=line chosen for setting
up the underlying transport
flow </c><c>M</c><c>TRANSPORT </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC5285 - RTP Header Extensions">
<t>
<xref target="RFC5285"/> provides a general
mechanism to use the header extension feature of RTP (the
Real-Time Transport Protocol). It provides the option to
use a small number of small extensions in each RTP packet,
where the universe of possible extensions is large and
registration is de-centralized. The actual extensions in
use in a session are signaled in the setup information for
that session.
</t>
<texttable title="RFC5285 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>extmap </c><c>Specific RTP extension document MUST
be referred </c> <c>B</c><c>SPECIAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC3605 - RTCP attribute in SDP ">
<t>
Originally, SDP assumed that RTP and RTCP were carried on
consecutive ports. However, this is not always true when
NATs are involved. <xref target="RFC3605"/> specifies an
early mechanism to indicate the RTCP port.
</t>
<texttable title="RFC3605 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>rtcp </c><c>Identical attribute value
MUST be used since the RTCP port affects
the entire RTP session. </c><c>M</c>
<c>IDENTICAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC5576 - Source-Specific SDP Attributes">
<t>
<xref target="RFC5576"/> defines a mechanism to
describe RTP media sources, which are identified by their
synchronization source (SSRC) identifiers, in SDP, to
associate attributes with these sources, and to express
relationships among sources. It also defines several
source-level attributes that can be used to describe
properties of media sources.</t>
<texttable title="RFC5576 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>ssrc </c><c>Refer to Notes
below </c><c>M</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>ssrc-group </c>
<c>Refer to section <xref target="SecssrcgroupAnalysis"></xref>
for specific analysis of the grouping semantics </c><c>M</c>
<c>SPECIAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>cname </c> <c>Not Impacted [Open Issues: what are
the rules for CNAME duplication across
sessions?] </c><c>SR</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>previous-ssrc </c>
<c>Refer to notes below </c><c>SR</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>fmtp </c><c>The attribute value must be same for a
given codec
configuration </c><c>SR</c><c>IDENTICAL-PER-PT </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
<t hangText="Note">
If SSRCs are repeated across m=lines being multiplexed, they
MUST all represent the same underlying RTP Source.
</t>
</section>
<section title="RFC7273 - RTP Clock Source Signalling">
<t>
<xref target="RFC7273"/> specifies
Session Description Protocol (SDP) signalling that identifies
timestamp reference clock sources and SDP signalling that identifies
the media clock sources in a multimedia session.</t>
<texttable title="RFC7273 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>ts-refclk </c><c>Not Impacted </c>
<c>S, M, SR</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>mediaclk </c>
<c>Not Impacted </c><c>S,, M, SR</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC6236 - Image Attributes in SDP">
<t>
<xref target="RFC6236"/> proposes a new generic
session setup attribute to make it possible to negotiate
different image attributes such as image size. A possible
use case is to make it possible for a low-end hand-held
terminal to display video without the need to rescale the
image,something that may consume large amounts of memory and
processing power. The document also helps to maintain an
optimal bitrate for video as only the image size that is
desired by the receiver is transmitted.
</t>
<texttable title="RFC6236 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>imageattr </c><c>The attribute value must be same
for a given codec configuration </c><c>M </c>
<c>IDENTICAL-PER-PT </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC7197 - Duplication Delay Attribute in SDP">
<t>
<xref target="RFC7197"/> defines an attribute to
indicate the presence of temporally redundant media streams
and the duplication delay in the Session Description
Protocol
</t>
<texttable title="RFC7197 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>duplication-delay </c><c>Not Impacted </c><c>B </c>
<c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC7226 - RTCP XR Blocks for MOS Metric Reporting">
<t>
<xref target="RFC7226"/> defines an RTP Control Protocol (RTCP)
Extended Report (XR) Block including two new segment types and
associated Session Description Protocol (SDP) parameters that allow
the reporting of mean opinion score (MOS) Metrics for use in a
range of RTP applications.
</t>
<texttable title="RFC7226 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>calgextmap </c><c>Not Impacted </c><c>B </c>
<c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC6285 - Rapid Acquisition of Multicast RTP Sessions">
<t>
<xref target="RFC6285"/> describes a method
using the existing RTP and RTP Control Protocol (RTCP)
machinery that reduces the acquisition delay. In this
method, an auxiliary unicast RTP session carrying the
Reference Information to the receiver precedes or
accompanies the multicast stream. This unicast RTP flow can
be transmitted at a faster than natural bitrate to further
accelerate the acquisition. The motivating use case for
this capability is multicast applications that carry
real-time compressed audio and video.
</t>
<texttable title="RFC6285 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>rams-updates </c><c>Not recommended
</c><c>M </c><c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC6230 - Media Control Channel Framework">
<t>
<xref target="RFC6230"/> describes a framework
and protocol for application deployment where the
application programming logic and media processing are
distributed. This implies that application programming
logic can seamlessly gain access to appropriate resources
that are not co-located on the same physical network entity.
The framework uses the Session Initiation Protocol (SIP) to
establish an application-level control mechanism between
application servers and associated external servers such as
media servers.
</t>
<texttable title="RFC6230 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>cfw-id </c><c>Not Applicable </c><c>M </c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC6364 - SDP Elements for FEC Framework">
<t>
<xref target="RFC6364"/> specifies the use of
the Session Description Protocol (SDP) to describe the
parameters required to signal the Forward Error Correction
(FEC) Framework Configuration Information between the
sender(s) and receiver(s). This document also provides
examples that show the semantics for grouping multiple
source and repair flows together for the applications that
simultaneously use multiple instances of the FEC Framework.
</t>
<texttable title="RFC6364 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>fec-source-flow </c><c> </c><c>M </c>
<c>SPECIAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>fec-repair-flow </c><c> </c><c>M </c>
<c>SPECIAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>repair-window </c><c> </c><c>M </c>
<c>SPECIAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC4796 - Content Attribute">
<t>
<xref target="RFC4796"/> defines a new Session
Description Protocol (SDP) media-level attribute, 'content'.
The 'content' attribute defines the content of the media
stream to a more detailed level than the media description
line. The sender of an SDP session description can attach
the 'content' attribute to one or more media streams. The
receiving application can then treat each media stream
differently (e.g., show it on a big or small screen) based
on its content.
</t>
<texttable title="RFC4796 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>content </c><c>Not
Impacted </c><c>M </c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC3407 - SDP Simple Capability Declaration">
<t>
<xref target="RFC3407"/> defines a set of
Session Description Protocol (SDP) attributes that enables
SDP to provide a minimal and backwards compatible capability
declaration mechanism.
</t>
<texttable title="RFC3407 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>sqn </c><c>Not Impacted </c>
<c>B</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>cdsc </c><c>Not
Impacted. </c><c>B</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>cpar </c><c>Refer to <xref target="encap"/> </c>
<c>B</c><c>INHERIT </c>
<c> </c><c> </c><c> </c><c> </c>
<c>cparmin </c><c>Refer to notes below </c>
<c>B</c><c>SPECIAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>cparmax </c><c>Refer to notes below </c>
<c>B</c><c>SPECIAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
<t hangText="Note"> Since the attributes (a=cparmin and
a=cparmax) define minimum and maximum numerical values
associated with the attributes described in a=cpar, it is
recommended to consult the document defining the attribute
for dealing under media stream multiplexing.
</t>
</section>
<section title="RFC6284 - Port Mapping between Unicast and Multicast RTP Sessions">
<t>
<xref target="RFC6284"/> presents a port
mapping solution that allows RTP receivers to choose their
own ports for an auxiliary unicast session in RTP
applications using both unicast and multicast services. The
solution provides protection against denial-of-service or
packet amplification attacks that could be used to cause one
or more RTP packets to be sent to a victim client
</t>
<texttable title="RFC6284 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>portmapping-req </c><c>Not recommended, if port mapping is
required by the application </c><c>M </c>
<c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC6714 - MSRP-CEMA">
<t>
<xref target="RFC6714"/> defines a Message
Session Relay Protocol (MSRP) extension, Connection
Establishment for Media Anchoring (CEMA). Support of this
extension is OPTIONAL. The extension allows middle boxes to
anchor the MSRP connection, without the need for middle
boxes to modify the MSRP messages; thus, it also enables
secure end-to-end MSRP communication in networks where such
middle boxes are deployed. This document also defines a
Session Description Protocol (SDP) attribute, 'msrp-cema',
that MSRP endpoints use to indicate support of the CEMA
extension.
</t>
<texttable title="RFC6714 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>msrp-cema </c><c>Not Impacted </c><c>M </c>
<c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC4583 - SDP Format for BFCP Streams">
<t>
<xref target="RFC4583"/> document specifies how
to describe Binary Floor Control Protocol (BFCP) streams in
Session Description Protocol (SDP) descriptions. User agents
using the offer/answer model to establish BFCP streams use
this format in their offers and answers
</t>
<texttable title="RFC4583 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>floorctrl </c>
<c>Must be repeated across all the multiplexed
m=lines </c>
<c>M </c><c>IDENTICAL </c><c> </c><c> </c>
<c> </c><c> </c>
<c>confid </c><c>Not Impacted </c><c>M </c>
<c>NORMAL </c><c> </c><c> </c><c> </c><c> </c>
<c>userid </c><c>Not
Impacted </c><c>M </c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>floorid </c>
<c>The floorid MUST be globally unique </c>
<c>M </c><c>NORMAL </c><c> </c><c> </c>
<c> </c><c> </c>
</texttable>
</section>
<section title="RFC5547 - SDP Offer/Answer for File Transfer">
<t>
<xref target="RFC5547"/> provides a mechanism
to negotiate the transfer of one or more files between two
endpoints by using the Session Description Protocol (SDP)
offer/answer model specified in <xref target="RFC3264"/>.
</t>
<texttable title="RFC5547 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>file-selector </c><c>Not Impacted </c>
<c>M</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>file-transfer-id </c><c>Not Impacted </c>
<c>M</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c> file-disposition </c><c>Not Impacted </c>
<c>M</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c> file-date </c><c>Not Impacted </c>
<c>M</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c> file-iconfile-range </c><c>Not Impacted </c>
<c>M</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC6489 - SDP and RTP Media Loopback Extension">
<t>
<xref target="RFC6489"/> adds new SDP media
types and attributes, which enable establishment of media
sessions where the media is looped back to the
transmitter. Such media sessions will serve as monitoring
and troubleshooting tools by providing the means for
measurement of more advanced VoIP, Real-time Text and Video
over IP performance metrics.
</t>
<texttable title="An Extension to the Session Description Protocol (SDP)
and Real-time Transport Protocol (RTP) for Media Loopback">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>loopback rtp-pkt-loopback </c><c>Not Impacted </c>
<c>M</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>loopback rtp-media-loopback </c><c>Not Impacted </c>
<c>M</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>loopback-source </c><c>Not Impacted </c><c>M</c>
<c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>loopback-mirror </c><c>Not Impacted </c><c>M</c>
<c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC5760 - RTCP with Unicast Feedback ">
<t>
<xref target="RFC5760"/> specifies an extension
to the Real-time Transport Control Protocol (RTCP) to use
unicast feedback to a multicast sender. The proposed
extension is useful for single-source multicast sessions
such as Source-Specific Multicast (SSM) communication where
the traditional model of many-to-many group communication is
either not available or not desired.
</t>
<texttable title="RFC5760 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>rtcp-unicast </c><c>The attribute MUST be reported
across all m=lines
multiplexed </c><c>M</c><c>IDENTICAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC3611 - RTCP XR">
<t>
<xref target="RFC3611"/> defines the Extended
Report (XR) packet type for the RTP Control Protocol (RTCP),
and defines how the use of XR packets can be signaled by an
application if it employs the Session Description Protocol
(SDP).
</t>
<texttable title="RFC3611 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>rtcp-xr </c><c>Not Impacted </c><c>B</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC5939 - SDP Capability Negotiation">
<t>
<xref target="RFC5939"/> defines a general SDP
Capability Negotiation framework. It also specifies how to
provide attributes and transport protocols as capabilities
and negotiate them using the framework. Extensions for
other types of capabilities (e.g., media types and media
formats) may be provided in other documents.
</t>
<texttable title="RFC5939 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>pcfg </c><c>Refer to Section <xref target="encap"/> </c>
<c>M</c><c>SPECIAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>acfg </c><c>Refer to Section <xref target="encap"/> </c>
<c>M</c><c>SPECIAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>csup </c><c>Not Impacted </c><c>B</c>
<c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>creq </c><c>Not Impacted </c><c>B</c>
<c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>acap </c><c>Refer to section <xref target="encap"/> </c>
<c>B</c><c>INHERIT </c>
<c> </c><c> </c><c> </c><c> </c>
<c>tcap </c><c>Refer to section <xref target="encap"/> </c>
<c>B</c><c>INHERIT </c>
<c> </c><c> </c><c> </c><c> </c>
<c>cap-v0 </c><c>Not Impacted </c>
<c>B</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC6871- SDP Media Capabilities Negotiation">
<t>
Session Description Protocol (SDP) capability negotiation
provides a general framework for indicating and negotiating
capabilities in SDP. The base framework defines only
capabilities for negotiating transport protocols and
attributes. <xref target="RFC6871"></xref> extends the
framework by defining media capabilities that can be used to
negotiate media types and their associated parameters.
</t>
<texttable title="Session Description Protocol (SDP)
Media Capabilities Negotiation">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>rmcap </c>
<c>Refer to Section <xref target="encap"/> </c>
<c>B</c><c>IDENTICAL-PER-PT </c>
<c> </c><c> </c><c> </c><c> </c>
<c>omcap </c><c>Not Impacted </c>
<c>B</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>mfcap </c>
<c>Refer to Section <xref target="encap"/> </c>
<c>B</c><c>IDENTICAL-PER-PT </c>
<c> </c><c> </c><c> </c><c> </c>
<c>mscap </c>
<c>Refer to Section <xref target="encap"/> </c>
<c>B</c><c>INHERIT </c>
<c> </c><c> </c><c> </c><c> </c>
<c>lcfg </c>
<c>Refer to Section <xref target="encap"/> </c>
<c>B</c><c>SPECIAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>sescap </c>
<c>Refer to Section <xref target="encap"/> </c>
<c>S</c><c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>med-v0 </c><c>Not Impacted </c>
<c>S</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
<t hangText="Note"> The "sescap" attribute is NOT RECOMMENDED for use with
multiplexing. The reason is that it requires the use of unique configuration
numbers across the entire SDP (per <xref target="RFC6871"/> as opposed to
within a media description only (per <xref target="RFC5939"/>).
As described in Section 15, the use of identical configuration numbers
between multiplxed (bundled) media descriptions is the default way of
indicating compatible configurations in a bundle.
</t>
</section>
<section title="RFC7006 - Miscellaneous Capabilities Negotiation SDP">
<t>
<xref target="RFC7006"/> extends the SDP capability negotiation framework to
allow endpoints to negotiate three additional SDP capabilities. In
particular, this memo provides a mechanism to negotiate bandwidth
("b=" line), connection data ("c=" line), and session or media titles
("i=" line for each session or media).
</t>
<texttable title="Miscellaneous Capabilities Negotiation in the
Session Description Protocol (SDP)">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>bcap </c><c>Inherit the category SUM as
applicable to b= attribute </c>
<c>B</c><c>INHERIT </c>
<c> </c><c> </c><c> </c><c> </c>
<c>bcap-v0 </c><c>Not Impacted </c>
<c>B</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>ccap </c><c>The connection address type
MUST be identical across
all the multiplexed m= lines. </c>
<c>B</c><c>IDENTICAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>ccap-v0 </c><c>Not Impacted. </c>
<c>B</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>icap </c><c>Not Impacted </c>
<c>B</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>icap-v0 </c><c>Not Impacted </c>
<c>B</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC4567 - Key Management Extensions for SDP and RTSP">
<t>
<xref target="RFC4567"/> defines general
extensions for Session Description Protocol (SDP) and Real
Time Streaming Protocol (RTSP) to carry messages, as
specified by a key management protocol, in order to secure
the media. These extensions are presented as a framework,
to be used by one or more key management protocols. As
such, their use is meaningful only when complemented by an
appropriate key management protocol.
</t>
<texttable title="RFC4567 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>key-mgmt </c><c>Key management protocol MUST be
identical across all the m=lines </c><c>B</c>
<c>IDENTICAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>mikey </c><c>Key management protocol MUST be
identical across all the m=lines </c><c>B</c>
<c>IDENTICAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC4572 - Comedia over TLS in SDP">
<t>
<xref target="RFC4572"/> specifies how to
establish secure connection-oriented media transport
sessions over the Transport Layer Security (TLS) protocol
using the Session Description Protocol (SDP). It defines a
new SDP protocol identifier, 'TCP/TLS'. It also defines the
syntax and semantics for an SDP 'fingerprint' attribute that
identifies the certificate that will be presented for the
TLS session. This mechanism allows media transport over TLS
connections to be established securely, so long as the
integrity of session descriptions is assured.
</t>
<texttable title="RFC4572 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>fingerprint </c><c>Fingerprint value from the m=line
defining the underlying transport is
chosen </c><c>B</c><c>TRANSPORT </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC4570 - SDP Source Filters">
<t>
<xref target="RFC4570"/> describes how to adapt
the Session Description Protocol (SDP) to express one or
more source addresses as a source filter for one or more
destination "connection" addresses. It defines the syntax
and semantics for an SDP "source-filter" attribute that may
reference either IPv4 or IPv6 address(es) as either an
inclusive or exclusive source list for either multicast or
unicast destinations. In particular, an inclusive
source-filter can be used to specify a Source-Specific
Multicast (SSM) session
</t>
<texttable title="RFC4570 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>source-filter </c><c>The attribute MUST be repeated
across all m=lines
multiplexed </c><c>B</c><c>IDENTICAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC6128 - RTCP Port for Multicast Sessions">
<t>
The Session Description Protocol (SDP) has an attribute that
allows RTP applications to specify an address and a port
associated with the RTP Control Protocol (RTCP) traffic. In
RTP-based source-specific multicast (SSM) sessions, the same
attribute is used to designate the address and the RTCP port
of the Feedback Target in the SDP description. However, the
RTCP port associated with the SSM session itself cannot be
specified by the same attribute to avoid ambiguity, and
thus, is required to be derived from the "m=" line of the
media description. Deriving the RTCP port from the "m="
line imposes an unnecessary restriction. <xref
target="RFC6128"/> removes this restriction by
introducing a new SDP attribute.
</t>
<texttable title="RFC6128 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>multicast-rtcp </c><c>Multicast RTCP port MUST be
identical across all the
m=lines </c><c>B</c><c>IDENTICAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC6189 - ZRTP">
<t>
<xref target="RFC6189"/> defines ZRTP, a protocol for media
path Diffie-Hellman exchange to agree on a session key and
parameters for establishing unicast Secure
Real-time Transport Protocol (SRTP) sessions for Voice over
IP (VoIP) applications.
</t>
<texttable title="RFC6189 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>zrtp-hash </c><c>Complicates if all the m=lines are
not authenticated as given in the example
below </c><c>M</c>
<c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
<t>
Example: Multiplexing media descriptions having attribute
zrtp-hash defined with the media descriptions lacking it,
would either complicate the handling of multiplexed stream
or fail multiplexing.
<figure>
<artwork align="left" alt="" height="" name="" type="" width=""
xml:space="preserve"><![CDATA[
v=0
o=bob 2890844527 2890844527 IN IP4 client.biloxi.example.com
s=
c=IN IP4 client.biloxi.example.com
t=0 0
m=audio 3456 RTP/AVP 97
a=rtpmap:97 iLBC/8000
<allOneLine>
a=zrtp-hash:1.10 fe30efd02423cb054e50efd0248742ac7a52c8f91bc2
df881ae642c371ba46df
</allOneLine>
m=video 34567 RTP/AVP 31
a=rtpmap:31 H261/90000
]]></artwork>
</figure>
</t>
</section>
<section title="RFC4145 - Connection-Oriented Media ">
<t>
<xref target="RFC4145"/> describes how to
express media transport over TCP using the Session
Description Protocol (SDP). It defines the SDP 'TCP'
protocol identifier, the SDP 'setup' attribute, which
describes the connection setup procedure, and the SDP
'connection' attribute, which handles connection
reestablishment.
</t>
<texttable title="RFC4145 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>setup </c><c>MUST be identical across all m=lines </c>
<c>B</c><c>IDENTICAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>connection </c><c>MUST be identical across all m=lines </c>
<c>B</c><c>IDENTICAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC6947 - The SDP ALTC Attribute">
<t>
<xref target="RFC6947"/> proposes a mechanism that allows
the same SDP offer to carry multiple IP addresses of different
address families (e.g., IPv4 and IPv6). The proposed attribute,
the "altc" attribute, solves the backward-compatibility problem
that plagued Alternative Network Address Types (ANAT) due to
their syntax.
</t>
<texttable title="RFC6947 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>altc </c><c>The IP Address and port must be the one
that corresponds to the m=line chosen for setting up the
underlying transport flow. </c>
<c>M</c><c>TRANSPORT </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC7195 - SDP Extension for Circuit Switched Bearers
in PSTN">
<t>
<xref target="RFC7195"/> describes use cases, requirements, and
protocol extensions for using the Session Description Protocol
(SDP) offer/answer model for establishing audio and video media
streams over circuit-switched bearers in the Public Switched
Telephone Network (PSTN).
</t>
<texttable title="RFC7195 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>cs-correlation:callerid </c><c>Not Impacted. </c>
<c>M</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>cs-correlation:uuie </c><c>Not Impacted. </c>
<c>M</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>cs-correlation:dtmf </c><c>Not Impacted. </c>
<c>M</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>cs-correlation:external </c><c>Not Impacted. </c>
<c>M</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC7272 - IDMS Using the RTP Control Protocol (RTCP)">
<t>
<xref target="RFC7272"/> defines a new RTP Control Protocol
(RTCP) Packet Type and an RTCP Extended Report (XR) Block Type
to be used for achieving Inter-Destination Media Synchronization
(IDMS).
</t>
<texttable title="RFC7272 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>rtcp-idms </c><c>Not Impacted. </c>
<c>M</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC5159 - OMA BCAST SDP Attributes">
<t>
<xref target="RFC5159"/> provides descriptions
of Session Description Protocol (SDP) attributes used by the
Open Mobile Alliance's Broadcast Service and Content
Protection specification.
</t>
<texttable title="RFC5159 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>bcastversion </c><c>Not Impacted </c>
<c>S</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>stkmstream </c><c>Not Impacted </c>
<c>B</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>SRTPAuthentication </c><c>Not Impacted </c>
<c>M</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>SRTPROCTxRate </c><c>Not Impacted </c>
<c>M</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC6193 - Media Description for IKE in SDP">
<t>
<xref target="RFC6193"/> specifies how to
establish a media session that represents a virtual private
network using the Session Initiation Protocol for the
purpose of on-demand media/application sharing between
peers. It extends the protocol identifier of the Session
Description Protocol (SDP) so that it can negotiate use of
the Internet Key Exchange Protocol (IKE) for media sessions
in the SDP offer/answer model.
</t>
<texttable title="RFC6193 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>ike-setup </c><c>Attribute MUST be identical
across all the m=lines </c><c>B</c><c>IDENTICAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>psk-fingerprint </c><c>Attribute MUST be identical
across all the m=lines </c><c>B</c><c>IDENTICAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>ike-esp </c><c>Attribute MUST be identical
across all the m=lines </c><c>B</c><c>IDENTICAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>ike-esp-udpencap </c><c>Attribute MUST be identical
across all the m=lines </c><c>B</c><c>IDENTICAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
<t hangText="Note"> With the above SDP constraints, a session
multiplexed with multiple m=lines will use only one IPSec
association for all of the m= lines.
</t>
</section>
<section title="RFC6064 - SDP and RTSP Extensions for 3GPP">
<t>
The Packet-switched Streaming Service (PSS) and the
Multimedia Broadcast/Multicast Service (MBMS) defined by
3GPP use the Session Description Protocol (SDP) and Real
Time Streaming Protocol (RTSP) with some extensions. <xref
target="RFC6064"/> provides information about
these extensions and registers the RTSP and SDP extensions
with IANA.
</t>
<texttable title="RFC6064 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>X-predecbufsize </c>
<c>Refer to notes below </c>
<c>M</c><c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>X-initpredecbufperiod </c>
<c>Refer to notes below </c>
<c>M</c><c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>X-initpostdecbufperiod </c>
<c>Refer to notes below </c>
<c>M</c><c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>X-decbyterate</c><c>Refer to notes below </c>
<c>M</c><c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>3gpp-videopostdecbufsize </c>
<c>Refer to notes below </c>
<c>M</c><c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>framesize</c><c>Refer to notes below </c><c>M</c>
<c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>3GPP-Integrity-Key </c>
<c>Refer to notes below </c><c>S</c>
<c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>3GPP-SDP-Auth </c>
<c>Refer to notes below </c><c>S</c>
<c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>3GPP-SRTP-Config </c>
<c>Refer to notes below </c><c>M</c>
<c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>alt,alt-default-id </c>
<c>Refer to notes below </c>
<c>M</c><c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>alt-group </c>
<c>Refer to notes below </c><c>M</c>
<c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>3GPP-Adaptation-Support </c>
<c>Refer to notes below </c><c>M</c>
<c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>3GPP-Asset-Informatio </c>
<c>Refer to notes below </c><c>B</c>
<c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>mbms-mode </c>
<c>Refer to notes below </c><c>B</c>
<c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>mbms-flowid </c>
<c>Refer to notes below </c><c>M</c>
<c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>mbms-repair </c>
<c>Refer to notes below </c><c>B</c>
<c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>3GPP-QoE-Metrics:Corruption duration </c>
<c>Refer to notes below </c>
<c>M</c><c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>3GPP-QoE-Metrics:Rebuffering duration </c>
<c>Refer to notes below </c>
<c>M</c><c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>3GPP-QoE-Metrics:Initial buffering duration </c>
<c>Refer to notes below </c>
<c>M</c><c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>3GPP-QoE-Metrics:Successive loss of RTP packets </c>
<c>Refer to notes below </c>
<c>M</c><c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>3GPP-QoE-Metrics:Frame rate deviation </c>
<c>Refer to notes below </c>
<c>M</c><c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>3GPP-QoE-Metrics:Jitter duration </c>
<c>Refer to notes below </c>
<c>M</c><c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>3GPP-QoE-Metrics:Content Switch Time </c>
<c>Refer to notes below </c>
<c>B</c><c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>3GPP-QoE-Metrics:Average Codec Bitrat </c>
<c>Refer to notes below </c>
<c>M</c><c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>3GPP-QoE-Metrics:Codec Information </c>
<c>Refer to notes below </c>
<c>M</c><c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>3GPP-QoE-Metrics:Buffer Status </c>
<c>Refer to notes below </c>
<c>M</c><c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
<t hangText="Notes">
<xref target="RFC6064"/> defines SDP attributes that are
applicable in the declarative usage of SDP alone. For
purposes of this document, only the Offer/Answer usage of SDP
is considered as mandated by <xref
target="I-D.ietf-mmusic-sdp-bundle-negotiation"></xref>.
</t>
</section>
<section title="RFC3108 - ATM SDP">
<t>
<xref target="RFC3108">RFC3108</xref> describes conventions
for using the Session Description Protocol (SDP) described
for controlling ATM Bearer Connections, and any associated
ATM Adaptation Layer (AAL)
</t>
<texttable title="RFC3108 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>aalType </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>eecid </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>aalType </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>capability </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>qosClass </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>bcob </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>stc </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>upcc </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>atmQOSparms </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>atmTrfcDesc </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>abrParms </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>abrSetup </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>bearerType </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>lij </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>anycast </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>cache </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>bearerSigIE </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>aalApp </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>cbrRate </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>sbc </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>clkrec </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>fec </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>prtfl </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>structure </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>cpsSDUsize </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>aal2CPS </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>aal2CPSSDUrate </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>aal2sscs3661unassured </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>aal2sscs3661assured </c>
<c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>aal2sscs3662 </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>aal5sscop </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>atmmap </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>silenceSupp </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>ecan </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>gc </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>profileDesc </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>vsel </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>dsel </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>fsel </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>onewaySel </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>codecconfig </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>isup_usi </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>isup_usi </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c>chain </c><c>Not Impacted</c>
<c>B </c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
<t hangText="Note">RFC3108 describes conventions for using the
Session Description Protocol (SDP) for characterizing ATM
bearer connections using an AAL1, AAL2 or AAL5 adaptation
layers. For AAL1, AAL2 and AAL5, bearer connections can be
used to transport single media streams. In addition, for AAL1
and AAL2, multiple media streams may be multiplexed into a
bearer connection. For all adaptation types (AAL1, AAL2 and
AAL5), bearer connections may be bundled into a single media
group. In all cases addressed by RFC3108, a real-time media
stream (voice, video, voiceband data, pseudo-wire and others)
or a multiplex of media streams is mapped directly into an ATM
connection. RFC3108 does not address cases where ATM serves
as a low-level transport pipe for IP packets which in turn may
carry one or more real-time (e.g. VoIP) media sessions with a
life-cycle different from that of the underlying ATM
transport.
</t>
</section>
<section title="3GPP TS 26.114">
<t>
<xref target="R3GPPTS26.114"/> specifies IP multimedia subsystem:
Media handling and interaction
</t>
<texttable title="3GPP TS 24.182 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>3gpp_sync_info </c>
<c>Usage defined for the IP Multimedia Subsystem </c>
<c>M</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>3gpp_MaxRecvSDUSize </c>
<c>Usage defined for the IP Multimedia Subsystem </c>
<c>M</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="3GPP TS 24.182">
<t>
<xref target="R3GPPTS24.182"/> specifies IP multimedia subsystem
Custom Alerting tones
</t>
<texttable title="3GPP TS 24.182 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>g.3gpp.cat </c>
<c>Usage defined for the IP Multimedia Subsystem </c>
<c>M</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="3GPP TS 24.183">
<t>
<xref target="R3GPPTS24.183"/> specifies IP multimedia
subsystem Custom Ringing Signal
</t>
<texttable title="3GPP TS 24.183 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>g.3gpp.crs </c>
<c>Usage defined for the IP Multimedia Subsystem </c>
<c>M</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="3GPP TS 24.229">
<t>
<xref target="R3GPPTS24.229"/> specifies IP multimedia call
control protocol based on Session Initial protocol and
Session Description Protocol.
</t>
<texttable title="3GPP TS 24.229 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>secondary-realm </c>
<c>Per media-level attribute MUST be used per
underlying transport </c><c>M</c>
<c>TRANSPORT </c>
<c> </c><c> </c><c> </c><c> </c>
<c>visited-realm </c>
<c>Per media-level attribute MUST be used per
underlying transport </c><c>M</c>
<c>TRANSPORT </c><c> </c>
<c> </c><c> </c><c> </c>
<c>omr-m-cksum </c><c>Not Impacted </c>
<c>M</c><c>NORMAL </c><c> </c>
<c> </c><c> </c><c> </c>
<c>omr-s-cksum </c><c>Not Impacted </c>
<c>M</c><c>NORMAL </c><c> </c>
<c> </c><c> </c><c> </c>
<c>omr-m-att </c><c>Not Impacted </c>
<c>M</c><c>NORMAL </c><c> </c>
<c> </c><c> </c><c> </c>
<c>omr-s-bw </c><c>Not Impacted </c>
<c>M</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>omr-s-bw </c><c>Not Impacted </c>
<c>M</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>omr-m-att </c><c>Not Impacted </c>
<c>M</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>omr-codecs </c><c>Not Impacted </c>
<c>M</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="ITU T.38">
<t>
<xref target="T.38"></xref> defines procedures for
real-time Group 3 facsimile communications over IP networks.
</t>
<texttable title="Historic Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>T38FaxVersion </c><c>Not Impacted </c>
<c>S</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>T38MaxBitRate </c><c>Not Impacted </c>
<c>S</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>T38FaxFillBitRemoval </c><c>Not Impacted </c>
<c>S</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>T38FaxTranscodingMMR </c><c>Not Impacted </c>
<c>S</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>T38FaxTranscodingJBIG </c><c>Not Impacted </c>
<c>S</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>T38FaxRateManagement </c><c>Not Impacted </c>
<c>S</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>T38FaxMaxBuffer </c><c>Not Impacted </c>
<c>S</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>T38FaxMaxDatagram </c><c>Not Impacted </c>
<c>S</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>T38FaxUdpEC </c><c>Not Impacted </c>
<c>S</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>T38FaxMaxIFP </c><c>Not Impacted </c>
<c>S</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>T38FaxUdpECDepth </c><c>Not Impacted </c>
<c>S</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>T38FaxUdpFECMaxSpan </c><c>Not Impacted </c>
<c>S</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>T38ModemType </c><c>Not Impacted </c>
<c>S</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
<t hangText="Note"> The ITU T.38 attributes are clearly unaffected
by multiplexing and are specific to the working of the fax
protocol itself.</t>
</section>
<section title="ITU-T-REC.Q1970">
<t>
<xref target="ITU-T-REC.Q1970"></xref> defines BICC IP bearer
control protocol.
</t>
<texttable title="ITU-T-REC.Q1970 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>ipbcp </c><c>Not Impacted </c>
<c>S</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="ITU-T H.248.15">
<t>
ITU-T H.248.15 <xref target="H.248.15"></xref> defines Gateway Control Protocol
SDP H.248 package attribute
</t>
<texttable title="Historic Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>h248item </c><c>It is also only applicable for
signaling the inclusion of H.248 extension packages to a
gateway via the local and remote descriptors. The attribute
itself is unaffected by multiplexing, but the packaged
referenced in a specific use of the attribute may be
impacted. Further analysis of each package is needed to
determine if there is an issue. This is only a concern in
environments using a decomposed server/gateway with H.248
signaled between them. The ITU-T will need to do further
analysis of various packages when they specify how to signal
the use of multiplexing to a gateway. </c>
<c>B</c><c>SPECIAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC4975 - The Message Session Relay Protocol">
<t>
<xref target="RFC4975"/> the Message Session
Relay Protocol, a protocol for transmitting a series of
related instant messages in the context of a session.
Message sessions are treated like any other media stream
when set up via a rendezvous or session creation protocol
such as the Session Initiation Protocol.
</t>
<texttable title="RFC4975 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>accept-types </c><c>Not Impacted </c>
<c>M </c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>accept-wrapped-types </c><c>Not Impacted </c>
<c>M </c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>max-size </c><c>Not Impacted </c>
<c>M </c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>path </c><c>Not Impacted </c>
<c>M </c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="Historical">
<t>
This section specifies analysis for the attributes that are
included for historic usage alone by the <xref
target="IANA"></xref>.
</t>
<texttable title="Unknowns Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>rtpred1 </c><c>Historic attributes. </c>
<c>Not-Applcable</c><c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>rtpred2 </c><c>Historic attributes. </c>
<c>Not-Applcable</c><c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>PSCid </c><c>Not Applicable </c>
<c>Not-Applcable</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>bc_service </c><c>Not Applicable </c>
<c>Not-Applcable</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>bc_program </c><c>Not Applicable </c>
<c>Not-Applcable</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>bc_service_package </c><c>Not Applicable </c>
<c>Not-Applcable</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
</section>
<section title="bwtype Attribute Analysis" anchor="SecbwtypeAnalysis" >
<t>
This section specifies handling of specific bandwidth attributes
when used in multiplexing scenarios.
</t>
<section title="RFC4566 - SDP: Session Description Protocol">
<texttable title="RFC4566 bwtype Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>bwtype:CT </c><c>Not Impacted </c>
<c>S</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>bwtype:AS </c><c> As a session attribute, it
specifies the session aggregate unless media-level b=RR
and/or b=RS attributes are used. Under this interpretation
the multiplexing scheme has no impact and thus NORMAL
category applies. </c>
<c>B</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>bwtype:AS </c><c> For the media level usage,
the aggregate of individual bandwidth values is considered. </c>
<c>B</c>
<c>SUM </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC3556 - SDP Bandwidth Modifiers for RTCP Bandwidth">
<t>
<xref target="RFC3556">RFC3556</xref> defines an extension to
the Session Description Protocol (SDP) to specify two
additional modifiers for the bandwidth attribute. These
modifiers may be used to specify the bandwidth allowed for
RTP Control Protocol (RTCP) packets in a Real-time Transport
Protocol (RTP) session
</t>
<texttable title="RFC3556 bwtype Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>bwtype:RS </c><c>Session level usage represents
session aggregate and media level usage indicates SUM of the
individual values while multiplexing </c>
<c>B</c><c>NORMAL</c>
<c> </c><c> </c><c> </c><c> </c>
<c>bwtype:RR </c><c>Session level usage represents
session aggregate and media level usage indicates SUM of the
individual values while multiplexing </c>
<c>B</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC3890 - Bandwidth Modifier for SDP">
<t>
<xref target="RFC3890">RFC3890</xref> defines a Session
Description Protocol (SDP) Transport Independent Application
Specific Maximum (TIAS) bandwidth modifier that does not
include transport overhead; instead an additional packet rate
attribute is defined. The transport independent bit-rate
value together with the maximum packet rate can then be used
to calculate the real bit-rate over the transport actually
used.
</t>
<texttable title="RFC3890 bwtype Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>bwtype:TIAS </c><c>The usage of TIAS is not clearly
defined Offer/Answer
usage. </c><c>B</c><c>SPECIAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>maxprate </c><c>The usage of TIAS and maxprate is not
well defined under multiplexing </c><c>B</c><c>SPECIAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
<t hangText="Note"> The intention of TIAS is that the media
level bit-rate is multiplied with the known per-packet overhead
for the selected transport and the maxprate value to determine
the worst case bit-rate from the transport to more accurately
capture the required usage. Summing TIAS values independently
across m=lines and multiplying the computed sum with maxprate
and the per-packet overhead would inflate the value
significantly. Instead performing multiplication and adding the
individual values is a more appropriate usage. This still
ignores the fact that this is a send side declaration, and not
intended for receiver negotiation.
</t>
</section>
</section>
<section title="rtcp-fb Attribute Analysis" anchor="SecrtcpfbAnalysis">
<t>
This section analyzes rtcp-fb SDP attributes.
</t>
<section title="RFC4585 - RTP/AVPF">
<t>
<xref target="RFC4585">RFC4585</xref> defines an extension to
the Audio-visual Profile (AVP) that enables receivers to
provide, statistically, more immediate feedback to the
senders and thus allows for short-term adaptation and
efficient feedback-based repair mechanisms to be implemented.
</t>
<texttable title="RFC4585 Attribute Analysis">
<ttcol align='left'>Attr Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>ack rpsi </c><c>The attribute value must be same
for a given codec configuration</c>
<c>M</c><c>IDENTICAL-PER-PT </c>
<c> </c><c> </c><c> </c><c> </c>
<c>ack app </c>
<c>Feedback parameters MUST be handled in the app specific
way when multiplexed</c>
<c>M</c><c>SPECIAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>nack </c><c>The attribute value must be same
for a given codec configuration</c>
<c>M</c><c>IDENTICAL-PER-PT </c>
<c> </c><c> </c><c> </c><c> </c>
<c>nack pli </c><c>The attribute value must be same
for a given codec configuration</c>
<c>M</c><c>IDENTICAL-PER-PT </c>
<c> </c><c> </c><c> </c><c> </c>
<c>nack sli </c><c>The attribute value must be same
for a given codec configuration</c>
<c>M</c><c>IDENTICAL-PER-PT </c>
<c> </c><c> </c><c> </c><c> </c>
<c>nack rpsi </c><c>The attribute value must be same
for a given codec configuration </c>
<c>M</c><c>IDENTICAL-PER-PT </c>
<c> </c><c> </c><c> </c><c> </c>
<c>nack app </c>
<c>Feedback parameters MUST be handled in the app specific
way when multiplexed</c>
<c>M</c><c>SPECIAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>trr-int </c><c>The attribute value must be same
for a given codec configuration</c>
<c>M</c><c>IDENTICAL-PER-PT </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC5104 - Codec Control Messages in AVPF">
<t>
<xref target="RFC5104">RFC5104</xref> specifies a few
extensions to the messages defined in the Audio-Visual
Profile with Feedback (AVPF). They are helpful primarily in
conversational multimedia scenarios where centralized
multipoint functionalities are in use. However, some are
also usable in smaller multicast environments and
point-to-point calls.
</t>
<texttable title="RFC5104 Attribute Analysis">
<ttcol align='left'>Attr Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>ccm </c><c>The attribute value must be same
for a given codec configuration</c>
<c>M</c><c>IDENTICAL-PER-PT </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC6285 - Unicast-Based RAMS">
<texttable title="RFC6285 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>nack rai </c><c>The attribute value must be same
for a given codec configuration </c>
<c>M </c><c>IDENTICAL-PER-PT </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC6679 - ECN for RTP over UDP/IP">
<t>
<xref target="RFC6679">RFC6679</xref> specifies how Explicit
Congestion Notification (ECN) can be used with the Real-time
Transport Protocol (RTP) running over UDP, using the RTP
Control Protocol (RTCP) as a feedback mechanism. It defines
a new RTCP Extended Report (XR) block for periodic ECN
feedback, a new RTCP transport feedback message for timely
reporting of congestion events, and a Session Traversal
Utilities for NAT (STUN) extension used in the optional
initialization method using Interactive Connectivity
Establishment (ICE)
</t>
<texttable title="RFC6679 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>ecn-capable-rtp </c><c>ECN markup are enabled at the
RTP Session level </c>
<c>M </c><c>IDENTICAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>nack ecn </c><c>This attribute enables ECN at the RTP
session level </c>
<c>M </c><c>IDENTICAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC6642 - Third-Party Loss Report">
<t>
In a large RTP session using the RTP Control Protocol (RTCP)
feedback mechanism defined in RFC 4585 <xref
target="RFC4585"></xref>, a feedback target may experience
transient overload if some event causes a large number of
receivers to send feedback at once. This overload is usually
avoided by ensuring that feedback reports are forwarded to
all receivers, allowing them to avoid sending duplicate
feedback reports. However, there are cases where it is not
recommended to forward feedback reports, and this may allow
feedback implosion. RFC6642 <xref target="RFC6642"></xref>
memo discusses these cases and defines a new RTCP Third-Party
Loss Report that can be used to inform receivers that the
feedback target is aware of some loss event, allowing them to
suppress feedback. Associated Session Description Protocol
(SDP) signaling is also defined.
</t>
<texttable title="RFC6642 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>nack tllei </c><c>The attribute value must be same
for a given codec configuration </c>
<c>M </c>
<c>IDENTICAL-PER-PT </c>
<c> </c><c> </c><c> </c><c> </c>
<c>nack pslei </c><c>The attribute value must be same
for a given codec configuration </c>
<c>M </c>
<c>IDENTICAL-PER-PT </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC5104 - Codec Control Messages in AVPF">
<texttable title="RFC5104 Attribute Analysis">
<ttcol align='left'>Attr Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>ccm fir </c><c>The attribute value must be same
for a given codec configuration</c>
<c>M</c><c>IDENTICAL-PER-PT </c>
<c> </c><c> </c><c> </c><c> </c>
<c>ccm tmmbr </c><c>The attribute value must be same
for a given codec configuration</c>
<c>M</c><c>IDENTICAL-PER-PT </c>
<c> </c><c> </c><c> </c><c> </c>
<c>ccm tstr </c><c>The attribute value must be same
for a given codec configuration</c>
<c>M</c><c>IDENTICAL-PER-PT </c>
<c> </c><c> </c><c> </c><c> </c>
<c>ccm vbcm </c><c>The attribute value must be same
for a given codec configuration</c>
<c>M</c><c>IDENTICAL-PER-PT </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
</section>
<section title="group Attribute Analysis"
anchor="SecgroupAnalysis">
<t>
This section analyzes SDP "group" semantics.
</t>
<section title="RFC5888 - SDP Grouping Framework">
<t>
<xref target="RFC5888">RFC5888</xref> defines a framework
to group "m" lines in the Session Description Protocol (SDP)
for different purposes.
</t>
<texttable title="RFC5888 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>group:LS </c><c>Not Impacted </c>
<c>S </c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>group:FID </c><c>Not Impacted </c>
<c>S </c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC3524 - Mapping Media Streams to
Resource Reservation Flows">
<t>
<xref target="RFC3524">RFC3524</xref> defines an extension to
the Session Description Protocol (SDP) grouping framework.
It allows requesting a group of media streams to be mapped
into a single resource reservation flow. The SDP syntax
needed is defined, as well as a new "semantics" attribute
called Single Reservation Flow (SRF).
</t>
<texttable title="RFC3524 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>group:SRF </c><c>Not Impacted </c>
<c>S </c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC4091 - ANAT Semantics">
<t>
<xref target="RFC4091">RFC4091</xref> defines the Alternative
Network Address Types (ANAT) semantics for the Session
Description Protocol (SDP) grouping framework. The ANAT
semantics allow alternative types of network addresses to
establish a particular media stream.
</t>
<texttable title="RFC4091 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>group:ANAT </c><c>ANAT semantics is obseleted </c>
<c>S </c>
<c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC5956 - FEC Grouping Semantics in SDP">
<t>
<xref target="RFC5956">RFC5956</xref> defines the semantics
for grouping the associated source and FEC-based (Forward
Error Correction) repair flows in the Session Description
Protocol (SDP). The semantics defined in the document are to
be used with the SDP Grouping Framework (RFC 5888). These
semantics allow the description of grouping relationships
between the source and repair flows when one or more source
and/or repair flows are associated in the same group, and
they provide support for additive repair flows. SSRC-level
(Synchronization Source) grouping semantics are also defined
in this document for Real-time Transport Protocol (RTP)
streams using SSRC multiplexing.
</t>
<texttable title="RFC5956 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>group:FEC-FR </c><c>Not Impacted </c><c>S </c>
<c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC5583 - Signaling Media Decoding Dependency in SDP">
<t>
<xref target="RFC5583">RFC5583</xref> defines semantics that
allow for signaling the decoding dependency of different
media descriptions with the same media type in the Session
Description Protocol (SDP). This is required, for example,
if media data is separated and transported in different
network streams as a result of the use of a layered or
multiple descriptive media coding process.
</t>
<texttable title="RFC5583 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>depend lay </c><c>The attribute value must be same
for a given codec configuration </c><c>M</c>
<c>IDENTICAL-PER-PT </c>
<c> </c><c> </c><c> </c><c> </c>
<c>depend mdc </c><c>The attribute value must be same
for a given codec configuration </c><c>M</c>
<c>IDENTICAL-PER-PT </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC7104 - Duplication Grouping Semantics in the SDP">
<t>
<xref target="RFC7104"/> defines the semantics for
grouping redundant streams in the Session Description Protocol (SDP).
The semantics defined in this document are to be used with the SDP
Grouping Framework. Grouping semantics at the Synchronization Source
(SSRC) level are also defined in this document for RTP streams using
SSRC multiplexing.
</t>
<texttable title="RFC7104 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>group:DUP </c><c>Not Impacted </c><c>S </c>
<c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
</section>
<section title="ssrc-group Attribute Analysis"
anchor="SecssrcgroupAnalysis">
<t>
This section analyzes "ssrc-group" semantics.
</t>
<section title="RFC5576 - Source-Specific SDP Attributes">
<texttable title="RFC5576 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>ssrc-group:FID </c><c>Not Impacted </c>
<c>M</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>ssrc-group:FEC </c><c>Not Impacted </c>
<c>M</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>ssrc-groupFEC-FR </c><c>Not Impacted </c>
<c>M</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
<section title="RFC7104 - Duplication Grouping Semantics in the SDP">
<texttable title="RFC7104 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>ssrc-group:DUP </c><c>Not Impacted </c><c>M</c>
<c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
</section>
<section title="QoS Mechanism Token Analysis"
anchor="SecqostokenAnalysis">
<t>
This section analyzes QoS tokes specified with SDP.
</t>
<section title="RFC5432 - QoS Mechanism Selection in SDP">
<texttable title="RFC5432 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>rsvp </c><c>Not Impacted, since QOS mechanisms are
applied per flow. </c>
<c>B</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>nsis </c><c>Not Impacted, since QOS mechanisms are
applied per flow. </c>
<c>B</c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
</section>
<section title="k= Attribute Analysis" anchor="SeckAnalysis">
<section title="RFC4566 SDP: Session Description Protocol">
<texttable title="RFC4566 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>k= </c><c>It is NOT recommended to use this attribute </c><c>S</c>
<c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
</section>
<section title="content Atribute Analysis" anchor="SeccontentAnalysis">
<section title="RFC4796">
<texttable title="RFC4796 Attribute Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>content:slides </c><c>Not Impacted </c>
<c>M </c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>content:speaker </c><c>Not Impacted </c>
<c>M </c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>content:main </c><c>Not Impacted </c>
<c>M </c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>content:sl </c><c>Not Impacted </c>
<c>M </c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
<c>content:alt </c><c>Not Impacted </c>
<c>M </c><c>NORMAL </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
</section>
</section>
<section anchor="sec-pay" title="Payload Formats">
<section title="RFC5109 - RTP Payload Format for Generic FEC">
<t>
<xref target="RFC5109"/> describes a payload
format for generic Forward Error Correction (FEC) for media
data encapsulated in RTP. It is based on the exclusive-or
(parity) operation. The payload format allows end systems
to apply protection using various protection lengths and
levels, in addition to using various protection group sizes
to adapt to different media and channel characteristics. It
enables complete recovery of the protected packets or
partial recovery of the critical parts of the payload
depending on the packet loss situation.
</t>
<texttable title="RFC5109 Payload Format Analysis">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Notes</ttcol>
<ttcol align='left'>Level</ttcol>
<ttcol align='left'>Category</ttcol>
<c>audio/ulpfec </c>
<c>Not recommended for multiplexing due to reuse of SSRCs </c>
<c>M</c><c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>video/ulpfec </c>
<c>Not recommended for multiplexing due to reuse of SSRCs </c>
<c>M</c><c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>text/ulpfec </c>
<c>Not recommended for multiplexing due to reuse of SSRCs </c>
<c>M</c><c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
<c>application/ulpfec </c>
<c>Not recommended for multiplexing due to reuse of SSRCs </c>
<c>M</c><c>NOT RECOMMENDED </c>
<c> </c><c> </c><c> </c><c> </c>
</texttable>
<t> Draft draft-lennox-payload-ulp-ssrc-mux proposes a simple
fix to make it possible to use ULP with multiplexing and ULP
is allowed when used with that. </t>
</section>
</section>
<section anchor="encap" title="Multiplexing Considerations for
Encapsulating Attributes">
<t>
This sections deals with recommendations for defining the
multiplexing characteristics of the SDP attributes that
encapsulate other SDP attributes/parameters. Such
attributes as of today, for example, are defined in
[RFC3407], [RFC5939] and [RFC6871] as part of a generic
framework for indicating and negotiating transport, media
and media format related capabilities in the SDP.
</t>
<t>
The behavior of such attributes under multiplexing is in
turn defined by the multiplexing behavior of the attributes
they encapsulate which are made known once the Offer/Answer
negotiation process is completed.
</t>
<section title="RFC3407 - cpar Attribute Analysis">
<t> RFC3407 capability parameter attribute (a=cpar)
encapsulates b= (bandwidth) or an a= attribute. For
bandwidth attribute encapsulation, the category SUM is
inherited. For the case of a= attribute, the category
corresponding to the SDP attribute being encapsulated is
inherited.
</t>
<t>
<figure>
<artwork align="left" alt="" height="" name="" type="" width=""
xml:space="preserve"><![CDATA[
v=0
o=alice 2890844526 2890844527 IN IP4 host.atlanta.example.com
s=
c=IN IP4 host.atlanta.example.com
t=0 0
m=video 3456 RTP/AVP 100
a=rtpmap:100 VP8/90000
a=sqn: 0
a=cdsc: 1 video RTP/AVP 100
a=cpar: a=rtcp-mux
m=video 3456 RTP/AVP 101
a=rtpmap:101 VP8/90000
a=fmtp:100 max-fr=15;max-fs=1200
a=cdsc: 2 video RTP/AVP 101
a=cpar: a=rtcp-mux
]]></artwork>
</figure>
</t>
<t> In the above example ,the category IDENTICAL is
inherited for the cpar encapsulated rtcp-mux
attribute. </t>
<t> </t>
</section>
<section title="RFC5939 Analysis">
<t>
<xref target="RFC5939"/> defines a general SDP
capability negotiation framework. It also specifies
how to provide transport protocols and SDP attributes
as capabilities and negotiate them using the
framework.
</t>
<t>
For this purpose, <xref target="RFC5939"/> defines the following
<list style="symbols">
<t>
A set of capabilities for the session and its
associated media stream components, supported
by each side. The attribute ("a=acap") defines
how to list an attribute name and its
associated value (if any) as a capability. The
attribute ("a=tcap") defines how to list
transport protocols (e.g., "RTP/AVP") as
capabilities.
</t>
<t>
A set of potential configurations ("a=pcfg") provided
by the offerer to indicate whcich combination of those
capabilities can be used for the session and its
associated media stream components. Potential
configurations are not ready for use until fully
negotiated. They provide an alternative that may
be used, subject to SDP capability negotiation
procedures. In particular the answerer may choose
one of the potential configurations for use as part
of the current Offer/Answer exchange.
</t>
<t>
An actual configuration ("a=acfg") for the session
and its associated media stream components. The
actual configuration identifies the potential
configuration that was negotiated for use. Use
of an actual configuration does not require
any further negotiation.
</t>
<t>
A negotiation process that takes the current
actual and the set of potential configurations
(combinations of capabilities) as input and
provides the negotiated actual configurations
as output. In <xref target="RFC5939"/> the
negotiation process is done independently for
each media description.
</t>
</list>
</t>
<section title="Recommendation - Procedures for Potential Configuration Pairing">
<t>
This section provides recommendations for entities
generating and processing SDP under the generic
capability negotiation framework as defined in
<xref target="RFC5939"/> under the context of media
stream multiplexing.
</t>
<t>
These recommendations are provided for the purposes
of enabling the Offerer to make sure that the
generated potential configurations between the
multiplexed streams can (easily) be negotiated to be
consistent between those streams. In particular, the
procedures aim to simply Answerer's procedure to choose
potential configurations that are consistent across
all the bundled media descriptions.
</t>
<t> A potential configuration selects a set of attributes
and parameters that become part of the media description
when negotiated. When multiplexing media descriptions with
potential configurations specified, there may be a need
for coordinating this selection between multiplexed media
descriptions ensuring right multiplexing behavior.</t>
<t> Although it is possible to analyze the various potential
configurations in bundled media descriptions to find combinations
that satisfy such constraints, it can quickly become complicated
to do so. </t>
<t> The procedures defined in <xref target="RFC5939"/> state
that each potential configuration in the SDP has a unique
configuration number, however the scope of uniqueness is
limited to each media description. To make it simple for the
answerer to chose valid combinations of potential configurations
across media descriptions in a given bundle group, we provide a
simple rule for constructiong potential configurations:-
<list style="symbols">
<t> Let m-bundle be the set of media descriptions that form
a given bundle .</t>
<t> Let m-bundle-pcfg be the set of media descriptions in
m-bundle that include one or more potential configurations.</t>
<t> Each media description in m-bundle-pcfg MUST have at
least one potential configuration with the same configuration
number (e.g. "1").</t>
<t> For each potential configuration with configuration number x
in m-bundle-pcfg, the offerer MUST ensure that if the answerer
chooses configuration number x in each of the media descriptions
in m-bundle-pcfg, then the resulting SDP will have all multiplexing
constraints satisfied for those media descriptions.</t>
<t> Since it is nearly impossible to define a generic
mechanism for various capability extensions , this
document does't provide procedures for dealing
with the capability extension attributes. However,
Section <xref target="med-cap-analysis"/> provide
analysis of media capability extension attributes
as defined in <xref target="RFC6871"/>. </t>
</list>
</t>
<t> The above allows the answerer to easily find multiplexing compatible
combinations of potential configurations:- The answerer simply choses a
potential configuration (number) that is present in all of the media
descriptions with potential configurations in the bundle.</t>
<t> Note that it is still possible for the offerer to provide additional
potential configurations with independent configuration numbers. The
answerer will have to perform more complicated analysis to determine
valid multiplexed combinations of those.</t>
<section title="Example: Transport Capability Multiplexing">
<figure title="">
<artwork><![CDATA[
v=0
o=alice 2890844526 2890844527 IN IP4 host.atlanta.example.com
s=
c=IN IP4 host.atlanta.example.com
t=0 0
a=tcap:1 RTP/SAVPF
a=tcap:2 RTP/SAVP
a=group:BUNDLE audio video
m= audio
a=mid:audio
a=pcfg:1 t=1
a=pcfg:2
m= video
a=mid:video
a=pcfg:1 t=1
a=pcfg:2 t=2
]]></artwork>
</figure>
<t>
In the example above, the potential
configurations that offer transport protocol
capability of RTP/SAVPF has the same
configuration number "1" in both the audio and
video media descriptions.
</t>
</section>
<section title="Example: Attribute Capability Multiplexing">
<figure title="">
<artwork><![CDATA[
v=0
o=alice 2890844526 2890844527 IN IP4 host.atlanta.example.com
s=
c=IN IP4 host.atlanta.example.com
t=0 0
a=acap:1 a=rtcp-mux
a=acap:2 a=crypto:1 AES_CM_128_HMAC_SHA1_80
inline:EcGZiNWpFJhQXdspcl1ekcmVCNWpVLcfHAwJSoj|2^20|1:32
a=group:BUNDLE audio video
m= audio 49172 RTP/AVP 99
a=mid:audio
a=pcfg:1 a=1
a=pcfg:2
m= video 560024 RTP/AVP 100
a=mid:video
a=pcfg:1 a=1
a=pcfg:2 a=2
]]></artwork>
</figure>
<t>
In the example above, the potential configuration
number 1 is repeated while referring to attribute
capability a=rtcp-mux, since the behavior is
IDENTICAL for the attribute a=rtcp-mux under
multiplexing.
</t>
</section>
</section>
</section>
<section title = "RFC6871 Analysis" anchor="med-cap-analysis">
<t>
<xref target="RFC6871"/> extends capability negotiation
framework described in <xref target="RFC5939"/> by
defining media capabilities that can be used to indicate
and negotiate media types and their associated format
parameters. It also allows indication of latent configurations
and session capabilities (the latter of which is not recommended for
use with bundled media as described in Section 5.29).
</t>
<section title="Recommendation: Dealing with Payload Type Numbers">
<t>
RFC 6871 defines a new payload type ("pt") parameter to be used
with the potential, actual and latent configuration parameters.
The parameter associates RTP payload type numbers with the
referenced RTP-based media format capabilities ("a=rmcap") defined
in [RFC6871] and is appropriate only when the transport protocol
uses RTP. This means that the same payload type number can be
assigned as part of potential or actual configurations in different
media descriptions in a bundle. There are rules for the usage of
identical Payload Type values across multiplexed m=lines as
described in [I-D.ietf-mmusic-sdp-bundle-negotiation], which MUST be
followed here as well. As described in Section 15.2, the use of
identical configuration numbers for compatible configurations in
different media descriptions that are part of the bundle provides a
way to ensure that the answerer can easily pick compatible
configurations here as well.
</t>
<section title="Example: Attribute Capability Under Shared Payload Type">
<t>
The attributes (a=rmcap, a=mfcap) follow the above
recommendations under mutliplexing
</t>
<figure title="">
<artwork><![CDATA[
v=0
o=- 25678 753849 IN IP4 192.0.2.1
s=
c=IN IP4 192.0.2.1
t=0 0
a=creq:med-v0
m=audio 54322 RTP/AVP 96
a=rtpmap:96 AMR-WB/16000/1
a=fmtp:96 mode-change-capability=1; max-red=220;
mode-set=0,2,4,7
a=rmcap:1,3 audio AMR-WB/16000/1
a=rmcap:2 audio AMR/8000/1
a=mfcap:1,2 mode-change-capability=1
a=mfcap:3 mode-change-capability=2
a=pcfg:1 m=1 pt=1:96
a=pcfg:2 m=2 pt=2:97
a=pcfg:3 m=3 pt=3:98
m=audio 54322 RTP/AVP 96
a=rtpmap:96 AMR-WB/16000/1
a=fmtp:96 mode-change-capability=1; max-red=220;
mode-set=0,2,4,7
a=rmcap:4 audio AMR/8000/1
a=rmcap:5 audio OPUS/48000/2
a=mfcap:5 minptime=40
a=mfcap:4 mode-change-capability=1
a=pcfg:1 m=4 pt=4:97
a=pcfg:4 m=5 pt=5:101
]]>
</artwork>
</figure>
<t>
In the example above, the potential configuration
number 1 is repeated when referring to media and media
format capability used for the Payload Type 97. This
implies that both the media capability 2 and 4 along
with their media format capabilities MUST refer to the
same codec configuration , as per the definition of
IDENTICAL-PER-PT
</t>
</section>
</section>
<section title="Recommendation: Dealing with Latent Configurations">
<t>
RFC 6871 adds the notion of a latent configurations, which provides
configuration information that may be used to guide a subsequent
offer/exchange, e.g. by adding another media stream or use alternative
codec combinations not currently offered. Latent configurations have
configuration numbers which cannot overlap with the potential configuration
numbers <xref target="RFC6871"/>. Supported combinations of potential and
latent configurations are indicated by use of the "a=sescap" attribute,
however use of this attribute is not recommended with bundled media,
since it requires the use of unique configuration numbers across the SDP.
Taken together, this means there is no well-defined way to indicate supported
combinations of latent configurations, or combinations of latent and potential
configurations with bundled media. It is still allowed to
use the latent configuration attribute, however the limitations
above will apply. To determine valid combinations, actual
negotiation will have to be attempted subsequently instead.
</t>
</section>
</section>
</section>
<section title="IANA Considerations">
<t>
[RFC EDITOR NOTE: Please replace RFCXXXX with the RFC number
of this document.]
</t>
<t>
The IANA is requested to add a new column named "Mux Category"
to all several of the registries in the "Session Description Protocol
(SDP) Parameters". Section <xref target="sec-mux-cat-iana"/> defines
the new registry for identifying the initial registrations for
"Mux Category" as proposed in this document. The tables in
<xref target="sec-mux-cat-values-iana"/> identify name of an entry in
the existing registry and specify the value to put in the
new "Mux Category" column of the associated IANA registry. Any entries in
the existing tables that do not have a value for the "Mux Category"
specified in this RFC will get a value of "TBD". Future specifications can
change the "TBD" entries to the correct value.
</t>
<section title="New Column 'Mux Category' " anchor="sec-mux-cat-iana" toc="default">
<t>
A new registry needs to be setup for specifying possible values for the
"Mux Category" column, with the following registrations created initially:
"NORMAL", "NOT RECOMMENDED", "IDENTICAL", "TRANSPORT", "IDENTICAL-PER-PT",
SPECIAL" and "TBD" as defined in this document.</t>
<t>Initial value registration for the column "Mux Category".</t>
<figure>
<artwork align="left"><![CDATA[
Value name: NORMAL
Reference : RFCXXXX
Value name: NOT RECOMMENDED
Reference : RFCXXXX
Value name: IDENTICAL
Reference : RFCXXXX
Value name: TRANSPORT
Reference : RFCXXXX
Value name: IDENTICAL-PER-PT
Reference : RFCXXXX
Value name: SPECIAL
Reference : RFCXXXX
Value name: TBD
Reference : RFCXXXX
]]></artwork>
</figure>
<t> Further entries may be registered on a first-come first-serve basis.
Each registration needs to indicate the "Mux Category" value and
identify the entries in the existing registries defined at
"Session Description Protocol (SDP) Parameters" to which the newly
registered "Mux Category" applies. For each new registration, it is
mandatory that a permanent, stable, and publicly accessible document
exists that specifies the semantics of the registered parameter in
the context of multiplexing and its applicability to existing
registered SDP parameters as stated above. The general registration
procedures of <xref target="RFC4566"/> apply.</t>
</section>
<section title="'Mux Category' values for SDP Registries" anchor="sec-mux-cat-values-iana" toc="default">
<t>
The various sub-sections below assigns the values to be used for the "Mux Category"
column for the corresponding registries idenfied.
</t>
<section title="Table: SDP bwtype">
<t> The following values are to be added to the 'SDP bwtype' registry
in the "Session Description Protocol (SDP) Parameters. The references
should be updated to point at this RFC as well as the previous
references. </t>
<texttable align="left">
<ttcol align='left'>Type</ttcol>
<ttcol align='left'>Mux Category</ttcol>
<c>CT </c><c>NORMAL </c>
<c>AS </c><c>SUM </c>
<c>RS </c><c>NORMAL </c>
<c>RR </c><c>NORMAL </c>
<c>TIAS </c><c>SPECIAL </c>
</texttable>
</section>
<section title="Table: att-field ">
<t> The following values are to be added to the 'att-field' registry
in the "Session Description Protocol (SDP) Parameters. The references
should be updated to point at this RFC as well as the previous
references. </t>
<texttable align="left">
<ttcol align='left'>SDP Name</ttcol>
<ttcol align='left'>Mux Category</ttcol>
<c>cat </c><c>NORMAL </c>
<c>keywds </c><c>NORMAL </c>
<c>type </c><c>NORMAL </c>
<c>type:broadcast </c><c>NORMAL </c>
<c>type:H332 </c><c>NORMAL </c>
<c>type:meeting </c><c>NORMAL </c>
<c>type:moderated </c><c>NORMAL </c>
<c>type:test </c><c>NORMAL </c>
<c>charset </c><c>NORMAL </c>
<c>charset:iso8895-1 </c><c>NORMAL </c>
<c>tool </c><c>NORMAL </c>
<c>ipbcp </c><c>NORMAL </c>
<c>group </c><c>NORMAL </c>
<c>ice-lite </c><c>NORMAL </c>
<c>ice-options </c><c>NORMAL </c>
<c>bcastversion </c><c>NORMAL </c>
<c>3GPP-Integrity-Key </c><c>NOT RECOMMENDED </c>
<c>3GPP-SDP-Auth </c><c>NOT RECOMMENDED </c>
<c>alt-group </c><c>NOT RECOMMENDED </c>
<c>PSCid </c><c>NORMAL </c>
<c>bc_service </c><c>NORMAL </c>
<c>bc_program </c><c>NORMAL </c>
<c>bc_service_package </c><c>NORMAL </c>
<c>sescap </c><c>NOT RECOMMENDED </c>
<c>rtsp-ice-d-m </c><c>TBD </c>
<c>recvonly </c><c>NORMAL </c>
<c>sendrecv </c><c>NORMAL </c>
<c>sendonly </c><c>NORMAL </c>
<c>sdplang </c><c>NORMAL </c>
<c>lang </c><c>NORMAL </c>
<c>h248item </c><c>SPECIAL </c>
<c>sqn </c><c>NORMAL </c>
<c>cdsc </c><c>NORMAL </c>
<c>cpar </c><c>INHERIT </c>
<c>cparmin </c><c>SPECIAL </c>
<c>cparmax </c><c>SPECIAL </c>
<c>rtcp-xr </c><c>NORMAL </c>
<c>maxprate </c><c>SPECIAL </c>
<c>setup </c><c>IDENTICAL </c>
<c>connection </c><c>IDENTICAL </c>
<c>key-mgmt </c><c>IDENTICAL </c>
<c>source-filter </c><c>IDENTICAL </c>
<c>inactive </c><c>NORMAL </c>
<c>fingerprint </c><c>TRANSPORT </c>
<c>flute-tsi </c><c>TBD </c>
<c>flute-ch </c><c>TBD </c>
<c>FEC-declaration </c><c>TBD </c>
<c>FEC-OTI-extension </c><c>TBD </c>
<c>content-desc </c><c>TBD </c>
<c>ice-pwd </c><c>TRANSPORT </c>
<c>ice-ufrag </c><c>TRANSPORT </c>
<c>stkmstream </c><c>NORMAL </c>
<c>qos-mech-send </c><c>NORMAL </c>
<c>qos-mech-recv </c><c>NORMAL </c>
<c>csup </c><c>NORMAL </c>
<c>creq </c><c>NORMAL </c>
<c>acap </c><c>INHERIT </c>
<c>tcap </c><c>INHERIT </c>
<c>3GPP-QoE-Metrics </c><c>NOT RECOMMENDED </c>
<c>3GPP-Asset-Information </c><c>NOT RECOMMENDED </c>
<c>mbms-mode </c><c>NORMAL </c>
<c>mbms-repair </c><c>NORMAL </c>
<c>ike-setup </c><c>IDENTICAL </c>
<c>psk-fingerprint </c><c>IDENTICAL </c>
<c>multicast-rtcp </c><c>IDENTICAL </c>
<c>rmcap </c><c>IDENTICAL-PER-PT </c>
<c>omcap </c><c>NORMAL </c>
<c>mfcap </c><c>IDENTICAL-PER-PT </c>
<c>mscap </c><c>INHERIT </c>
<c>bcap </c><c>INHERIT </c>
<c>ccap </c><c>IDENTICAL </c>
<c>icap </c><c>NORMAL </c>
<c>3gpp_sync_info </c><c>NORMAL </c>
<c>3gpp_MaxRecvSDUSize </c><c>NORMAL </c>
<c>etag </c><c>TBD </c>
<c>duplication-delay </c><c>NORMAL </c>
<c>range </c><c>TBD </c>
<c>control </c><c>TBD </c>
<c>mtag </c><c>TBD </c>
<c>ts-refclk </c><c>NORMAL </c>
<c>mediaclk </c><c>NORMAL </c>
<c>calgextmap </c><c>NORMAL </c>
<c>ptime </c><c>IDENTICAL-PER-PT </c>
<c>orient </c><c>NORMAL </c>
<c>orient:portrait </c><c>NORMAL </c>
<c>orient:landscape </c><c>NORMAL </c>
<c>orient:seascape </c><c>NORMAL </c>
<c>framerate </c><c>IDENTICAL-PER-PT </c>
<c>quality </c><c>NORMAL </c>
<c>rtpmap </c><c>IDENTICAL-PER-PT </c>
<c>fmtp </c><c>IDENTICAL-PER-PT </c>
<c>rtpred1 </c><c>NOT RECOMMENDED </c>
<c>rtpred2 </c><c>NOT RECOMMENDED </c>
<c>T38FaxVersion </c><c>NORMAL </c>
<c>T38MaxBitRate </c><c>NORMAL </c>
<c>T38MaxBitRate </c><c>NORMAL </c>
<c>T38FaxTranscodingMMR </c><c>NORMAL </c>
<c>T38FaxTranscodingJBIG </c><c>NORMAL </c>
<c>T38FaxRateManagement </c><c>NORMAL </c>
<c>T38FaxMaxBuffer </c><c>NORMAL </c>
<c>T38FaxMaxDatagram </c><c>NORMAL </c>
<c>T38FaxUdpEC </c><c>NORMAL </c>
<c>maxptime </c><c>IDENTICAL-PER-PT </c>
<c>des </c><c>NORMAL </c>
<c>curr </c><c>NORMAL </c>
<c>conf </c><c>NORMAL </c>
<c>mid </c><c>NORMAL </c>
<c>rtcp </c><c>IDENTICAL </c>
<c>rtcp-fb </c><c>IDENTICAL-PER-PT </c>
<c>label </c><c>NORMAL </c>
<c>T38VendorInfo </c><c>NORMAL </c>
<c>crypto </c><c>TRANSPORT </c>
<c>eecid </c><c>NORMAL </c>
<c>aalType </c><c>NORMAL </c>
<c>capability </c><c>NORMAL </c>
<c>qosClass </c><c>NORMAL </c>
<c>bcob </c><c>NORMAL </c>
<c>stc </c><c>NORMAL </c>
<c>upcc </c><c>NORMAL </c>
<c>atmQOSparms </c><c>NORMAL </c>
<c>atmQOSparms </c><c>NORMAL </c>
<c>abrParms </c><c>NORMAL </c>
<c>abrSetup </c><c>NORMAL </c>
<c>bearerType </c><c>NORMAL </c>
<c>lij </c><c>NORMAL </c>
<c>anycast </c><c>NORMAL </c>
<c>cache </c><c>NORMAL </c>
<c>bearerSigIE </c><c>NORMAL </c>
<c>aalApp </c><c>NORMAL </c>
<c>cbrRate </c><c>NORMAL </c>
<c>sbc </c><c>NORMAL </c>
<c>clkrec </c><c>NORMAL </c>
<c>fec </c><c>NORMAL </c>
<c>prtfl </c><c>NORMAL </c>
<c>structure </c><c>NORMAL </c>
<c>cpsSDUsize </c><c>NORMAL </c>
<c>all2CPS </c><c>NORMAL </c>
<c>all2CPSSDUrate </c><c>NORMAL </c>
<c>aal2sscs3661unassured </c><c>NORMAL </c>
<c>aal2sscs3661assured </c><c>NORMAL </c>
<c>aal2sscs3662 </c><c>NORMAL </c>
<c>aal5sscop </c><c>NORMAL </c>
<c>atmmap </c><c>NORMAL </c>
<c>silenceSupp </c><c>NORMAL </c>
<c>ecan </c><c>NORMAL </c>
<c>gc </c><c>NORMAL </c>
<c>profileDesc </c><c>NORMAL </c>
<c>vsel </c><c>NORMAL </c>
<c>dsel </c><c>NORMAL </c>
<c>fsel </c><c>NORMAL </c>
<c>onewaySel </c><c>NORMAL </c>
<c>codecConfig </c><c>NORMAL </c>
<c>isup_usi </c><c>NORMAL </c>
<c>uiLayer1_Prot </c><c>NORMAL </c>
<c>chain </c><c>NORMAL </c>
<c>floorctrl </c><c>IDENTICAL </c>
<c>confid </c><c>NORMAL </c>
<c>userid </c><c>NORMAL </c>
<c>floorid </c><c>NORMAL </c>
<c>FEC </c><c>NORMAL </c>
<c>profileDesc </c><c>NORMAL </c>
<c>accept-types </c><c>NORMAL </c>
<c>accept-wrapped-types </c><c>NORMAL </c>
<c>max-size </c><c>NORMAL </c>
<c>path </c><c>NORMAL </c>
<c>dccp-service-code </c><c>NOT RECOMMENDED </c>
<c>rtcp-mux </c><c>IDENTICAL </c>
<c>candidate </c><c>TRANSPORT </c>
<c>ice-mismatch </c><c>NORMAL </c>
<c>remote-candidates </c><c>TRANSPORT </c>
<c>SRTPAuthentication </c><c>NORMAL </c>
<c>SRTPROCTxRate </c><c>NORMAL </c>
<c>rtcp-rsize </c><c>IDENTICAL </c>
<c>file-selector </c><c>NORMAL </c>
<c>file-transfer-id </c><c>NORMAL </c>
<c>file-disposition </c><c>NORMAL </c>
<c>file-date </c><c>NORMAL </c>
<c>file-icon </c><c>NORMAL </c>
<c>file-range </c><c>NORMAL </c>
<c>depend </c><c>IDENTICAL-PER-PT </c>
<c>ssrc </c><c>NORMAL </c>
<c>ssrc-group </c><c>NORMAL </c>
<c>rtcp-unicast </c><c>IDENTICAL </c>
<c>pcfg </c><c>SPECIAL </c>
<c>acfg </c><c>SPECIAL </c>
<c>zrtp-hash </c><c>NOT RECOMMENDED </c>
<c>X-predecbufsize </c><c>NOT RECOMMENDED </c>
<c>X-initpredecbufperiod </c><c>NOT RECOMMENDED </c>
<c>X-initpostdecbufperiod </c><c>NOT RECOMMENDED </c>
<c>X-decbyterate </c><c>NOT RECOMMENDED </c>
<c>3gpp-videopostdecbufsize </c><c>NOT RECOMMENDED </c>
<c>framesize </c><c>NOT RECOMMENDED </c>
<c>3GPP-SRTP-Config </c><c>NOT RECOMMENDED </c>
<c>alt </c><c>NOT RECOMMENDED </c>
<c>alt-default-id </c><c>NOT RECOMMENDED </c>
<c>3GPP-Adaption-Support </c><c>NOT RECOMMENDED </c>
<c>mbms-flowid </c><c>NOT RECOMMENDED </c>
<c>fec-source-flow </c><c>SPECIAL </c>
<c>fec-repair-flow </c><c>SPECIAL </c>
<c>repair-window </c><c>SPECIAL </c>
<c>rams-updates </c><c>NOT RECOMMENDED </c>
<c>imageattr </c><c>IDENTICAL-PER-PT </c>
<c>cfw-id </c><c>NORMAL </c>
<c>portmapping-req </c><c>NOT RECOMMENDED </c>
<c>g.3gpp.cat </c><c>NORMAL </c>
<c>g.3gpp.crs </c><c>NORMAL </c>
<c>ecm-capable-rtp </c><c>IDENTICAL-PER-PT </c>
<c>visited-realm </c><c>TRANSPORT </c>
<c>secondary-realm </c><c>TRANSPORT </c>
<c>omr-s-cksum </c><c>NORMAL </c>
<c>omr-m-Cksum </c><c>NORMAL </c>
<c>omr-codecs </c><c>NORMAL </c>
<c>omr-codecs </c><c>NORMAL </c>
<c>omr-m-att </c><c>NORMAL </c>
<c>omr-m-bw </c><c>NORMAL </c>
<c>omr-s-bw </c><c>NORMAL </c>
<c>msrcp-cema </c><c>NORMAL </c>
<c>dccp-port </c><c>NOT RECOMMENDED </c>
<c>resource </c><c>NORMAL </c>
<c>channel </c><c>NORMAL </c>
<c>cmid </c><c>NORMAL </c>
<c>content </c><c>NORMAL </c>
<c>lcfg </c><c>SPECIAL </c>
<c>loopback </c><c>NORMAL </c>
<c>loopback-source </c><c>NORMAL </c>
<c>loopback-mirror </c><c>NORMAL </c>
<c>chatroom </c><c>TBD </c>
<c>altc </c><c>TRANSPORT </c>
<c>T38FaxMaxIFP </c><c>NORMAL </c>
<c>T38FaxUdpECDepth </c><c>NORMAL </c>
<c>T38FaxUdpFECMaxSpan </c><c>NORMAL </c>
<c>T38ModemType </c><c>NORMAL </c>
<c>cs-correlation </c><c>NORMAL </c>
<c>rtcpidms </c><c>NORMAL </c>
<c>cname </c><c>NORMAL </c>
<c>previous-ssrc </c><c>NORMAL </c>
<c>fmtp </c><c>IDENTICAL-PER-PT </c>
</texttable>
</section>
<section title="Table: content SDP Parameters">
<t> The following values are to be added to the 'content SDP Parameters'
registry in the "Session Description Protocol (SDP) Parameters.
The references should be updated to point at this RFC as well as
the previous references. </t>
<texttable align="left">
<ttcol align='left'>SDP Name</ttcol>
<ttcol align='left'>Mux Category</ttcol>
<c>slides </c><c>NORMAL </c>
<c>speaker </c><c>NORMAL </c>
<c>sl </c><c>NORMAL </c>
<c>main </c><c>NORMAL </c>
<c>alt </c><c>NORMAL </c>
</texttable>
</section>
<section title="Table: Semantics for the 'group' SDP Attribute">
<t> The following values are to be added to the
Semantics for the "group" SDP Attribute registry in the
"Session Description Protocol (SDP) Parameters.
The references should be updated to point at this RFC as well as
the previous references. </t>
<texttable align="left">
<ttcol align='left'>Token</ttcol>
<ttcol align='left'>Mux Category</ttcol>
<c>LS </c><c>NORMAL </c>
<c>FID </c><c>NORMAL </c>
<c>SRF </c><c>NORMAL </c>
<c>ANAT </c><c>NOT RECOMMENDED </c>
<c>FEC </c><c>NORMAL </c>
<c>FEC-FR </c><c>NORMAL </c>
<c>CS </c><c>NORMAL </c>
<c>DDP </c><c>NORMAL </c>
<c>DUP </c><c>NORMAL </c>
</texttable>
</section>
<section title="Table: 'rtcp-fb' Attribute Values">
<t> The following values are to be added to the
" 'rtcp-fb' Attribute Values" registry in the
"Session Description Protocol (SDP) Parameters.
The references should be updated to point at this RFC as well as
the previous references. </t>
<texttable align="left">
<ttcol align='left'>Value Name</ttcol>
<ttcol align='left'>Mux Category</ttcol>
<c>ack </c><c>IDENTICAL-PER-PT </c>
<c>app </c><c>SPECIAL </c>
<c>ccm </c><c>IDENTICAL-PER-PT </c>
<c>nack </c><c>IDENTICAL-PER-PT </c>
<c>trr-int </c><c>IDENTICAL-PER-PT </c>
</texttable>
</section>
<section title="Table: 'ack' and 'nack' Attribute Values">
<t> The following values are to be added to the
" 'ack' and 'nack' Attribute Values" registry in the
"Session Description Protocol (SDP) Parameters.
The references should be updated to point at this RFC as well as
the previous references. </t>
<texttable align="left">
<ttcol align='left'>Value Name</ttcol>
<ttcol align='left'>Mux Category</ttcol>
<c>sli </c><c>IDENTICAL-PER-PT </c>
<c>pli </c><c>IDENTICAL-PER-PT </c>
<c>rpsi </c><c>IDENTICAL-PER-PT </c>
<c>app </c><c>IDENTICAL-PER-PT </c>
<c>rai </c><c>IDENTICAL-PER-PT </c>
<c>tllei </c><c>IDENTICAL-PER-PT </c>
<c>pslei </c><c>IDENTICAL-PER-PT </c>
<c>ecn </c><c>IDENTICAL-PER-PT </c>
</texttable>
</section>
<section title="Table: 'depend' SDP Attribute Values">
<t> The following values are to be added to the
" 'depend' SDP Attribute Values" registry in the
"Session Description Protocol (SDP) Parameters.
The references should be updated to point at this RFC as well as
the previous references. </t>
<texttable align="left">
<ttcol align='left'>Token</ttcol>
<ttcol align='left'>Mux Category</ttcol>
<c>lay </c><c>NORMAL </c>
<c>mdc </c><c>NORMAL </c>
</texttable>
</section>
<section title="Table: 'cs-correlation' Attribute Values">
<t> The following values are to be added to the
" 'cs-correlation' Attribute Values" registry in the
"Session Description Protocol (SDP) Parameters.
The references should be updated to point at this RFC as well as
the previous references. </t>
<texttable align="left">
<ttcol align='left'>Token</ttcol>
<ttcol align='left'>Mux Category</ttcol>
<c>callerid </c><c>NORMAL </c>
<c>uuie </c><c>NORMAL </c>
<c>dtmf </c><c>NORMAL </c>
<c>external </c><c>NORMAL </c>
</texttable>
</section>
<section title="Table: Semantics for the 'ssrc-group' SDP Attribute">
<t> The following values are to be added to the
Semantics for the " 'ssrc-group' SDP Attribute" registry
in the "Session Description Protocol (SDP) Parameters.
The references should be updated to point at this RFC as well as
the previous references. </t>
<texttable align="left">
<ttcol align='left'>Token</ttcol>
<ttcol align='left'>Mux Category</ttcol>
<c>FID </c><c>NORMAL </c>
<c>FEC </c><c>NORMAL </c>
<c>FEC-FR </c><c>NORMAL </c>
<c>DUP </c><c>NORMAL </c>
</texttable>
</section>
<section title="Table: SDP/RTSP key management protocol identifiers">
<t> The following values are to be added to the
"SDP/RTSP key management protocol identifiers"
registry in the "Session Description Protocol (SDP) Parameters.
The references should be updated to point at this RFC as well as
the previous references. </t>
<texttable align="left">
<ttcol align='left'>Value Name</ttcol>
<ttcol align='left'>Mux Category</ttcol>
<c>mikey </c><c>IDENTICAL </c>
</texttable>
</section>
<section title="Table: Codec Control Messages">
<t> The following values are to be added to the
"Codec Control Messages" registry in the
"Session Description Protocol (SDP) Parameters.
The references should be updated to point at this RFC as well as
the previous references. </t>
<texttable align="left">
<ttcol align='left'>Value Name</ttcol>
<ttcol align='left'>Mux Category</ttcol>
<c>fir </c><c>IDENTICAL-PER-PT </c>
<c>tmmbr </c><c>IDENTICAL-PER-PT </c>
<c>tstr </c><c>IDENTICAL-PER-PT </c>
<c>vbcm </c><c>IDENTICAL-PER-PT </c>
</texttable>
</section>
<section title="Table: QoS Mechanism Tokens">
<t> The following values are to be added to the
"QoS Mechanism Tokens" registry in the
"Session Description Protocol (SDP) Parameters.
The references should be updated to point at this RFC as well as
the previous references. </t>
<texttable align="left">
<ttcol align='left'>QoS Mechanism</ttcol>
<ttcol align='left'>Mux Category</ttcol>
<c>rsvp </c><c>NORMAL </c>
<c>nsis </c><c>NORMAL </c>
</texttable>
</section>
<section title="Table: SDP Capability Negotiation Option Tags">
<t> The following values are to be added to the
"SDP Capability Negotiation Option Tags" Registry
in the "Session Description Protocol (SDP) Parameters.
The references should be updated to point at this RFC as well as
the previous references. </t>
<texttable align="left">
<ttcol align='left'>QoS Mechanism</ttcol>
<ttcol align='left'>Mux Category</ttcol>
<c>cap-v0 </c><c>NORMAL </c>
<c>med-v0 </c><c>NORMAL </c>
<c>bcap-v0 </c><c>NORMAL </c>
<c>ccap-v0 </c><c>NORMAL </c>
<c>icap-v0 </c><c>NORMAL </c>
</texttable>
</section>
<section title="Table: Timestamp Reference Clock Source Parameters">
<t> The following values are to be added to the
"Timestamp Reference Clock Source Parameters" Registry
in the "Session Description Protocol (SDP) Parameters.
The references should be updated to point at this RFC as well as
the previous references. </t>
<texttable align="left">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Mux Category</ttcol>
<c>ntp </c><c>NORMAL </c>
<c>ptp </c><c>NORMAL </c>
<c>gps </c><c>NORMAL </c>
<c>gal </c><c>NORMAL </c>
<c>glonass </c><c>NORMAL </c>
<c>local </c><c>NORMAL </c>
<c>private </c><c>NORMAL </c>
</texttable>
</section>
<section title="Table: Media Clock Source Parameters">
<t> The following values are to be added to the
"Media Clock Source Parameters" Registry
in the "Session Description Protocol (SDP) Parameters.
The references should be updated to point at this RFC as well as
the previous references. </t>
<texttable align="left">
<ttcol align='left'>Name</ttcol>
<ttcol align='left'>Mux Category</ttcol>
<c>sender </c><c>NORMAL </c>
<c>direct </c><c>NORMAL </c>
<c>IEEE1722 </c><c>NORMAL </c>
</texttable>
</section>
</section>
</section>
<section title="Security Considerations">
<t>
This document does not add any new security considerations
beyond the existing considerations in the RFC for protocols
that are being multiplexed together. </t>
<t>
The ways that SRTP streams are keyed is not believed to
create any two-time pad vulnerability for the currently
defined SRTP keying mechanism.
</t>
</section>
<section title="Acknowledgments">
<t>
I would like to thank Cullen Jennings for suggesting the
categories, contributing text and reviewing the draft. I would
also link to thank Magnus, Christer, Jonathan Lennox, Bo
Burman, and Dan on suggesting structural changes helping
improve the document readability.
</t>
<t>
I would like also to thank following experts on their inputs and
reviews as listed - Flemming Andreasen(5.20,5.28,5.29,15), Rohan Mahy(5.45),
Eric Burger(5.22),Christian Huitema(5.13), Christer Holmberg(5.17,5.22,5.40,5.41),
Richard Ejzak (5.36,5.42,5.43,5.44), Colin Perkins(5.7,5.8),
Magnus westerlund(5.2,5.3,5.9,5.26, 5.27,6.1,6.2,6.3,8.3,7),
Roni Evens(5.12,5.27,8.4), Subha Dhesikan(5.5,12.1,14),
Dan Wing(5.6,5.11,5.30,5.34,5.37),
Ali C Begen(5.1,5.16,5.18,5.21,5.33,8.2,8.4,13.1),
Bo Burman (7.2,7.6), Charles Eckel(5.14,5.23,5.24,9.1,8.5),
Paul Kyzivat(5.24), Ian Johansson(5.15), Saravanan Shanmugham(5.10),
Paul E Jones(5.25), Rajesh Kumar(5.39), Jonathan Lennox(5.31,5,14,11.1),
Mo Zanaty(5.4,5.19,8.1,8.3,8.5,12.1), Christian Huitema (5.13),
Qin Wu (5.38 PM-Dir review).
</t>
</section>
<section title="Change Log">
<t>[RFC EDITOR NOTE: Please remove this section when publishing]</t>
<t>Changes from draft-ietf-mmusic-sdp-mux-attributes-02
<list style="symbols">
<t>
Incorporated suggestions from Flemming on Capability Negotiation.
</t>
<t>
Closed open issues from IETF90
</t>
<t>
Added IANA section to list the categories for all the SDP attributes
anlayzed
</t>
<t>
Lots of cleanup
</t>
<t>
Reformatted Refernces section to use short-form notation
</t>
</list>
</t>
<t>Changes from draft-ietf-mmusic-sdp-mux-attributes-01
<list style="symbols">
<t>
Updated section 15 to provide detailed recommendation on dealing
with encapsulating attributes. Also updated sections 5.20,
5.28, 5.29 to refer to Section 15.
</t>
<t>
Added new categories IDENTICAL-PER-PT and INHERIT
</t>
<t>
Updated Sections 16 to add the new categories.
</t>
<t>
Updated Sections 5.1, 5.14, 5.15, 5.38, 8.5 to reflect the
category IDENTICAL-PER-PT.
</t>
<t>
Reformatted section 4 to add individual categories to their
own sections.
</t>
</list>
</t>
<t>Changes from draft-ietf-mmusic-sdp-mux-attributes-00
<list style="symbols">
<t>
Added Section 15 to provide recommendations on multiplexing
SDP encapsulating attributes. Also updated sections 5.20,
5.28, 5.29 to refer to Section 15.
</t>
<t>
Updated Section 5.38 to incorporate PM-dir review inputs from
Qin Wu
</t>
<t>
Updated Sections 5.2,5.14,8.5 to refer to BUNDLE draft for more clarity.
</t>
<t>
Fixed few nits regarding sentence clarity and fill-in the NOTES
section where information was lacking.
</t>
</list>
</t>
<t>Changes from draft-nandakumar-mmusic-mux-attributes-05
<list style="symbols">
<t>
Renamed the document to be a WG document.
</t>
<t>
Added Section 14.
</t>
<t>
Updated Open Issues based on IETF88 discussions.
</t>
</list>
</t>
<t>Changes from draft-nandakumar-mmusic-mux-attributes-04
<list style="symbols">
<t>
Added few OPEN ISSUES that needs to be discussed.
</t>
<t>
Updated sections 5.10,5.23,5,24,5,25,7.2,9.1,5.12,5.27,8.4,
5.44,5.11,5.4,5.19,10.1,10.5,5.21,10.4,15.1
</t>
<t>
Updated Table Column name Current to Level and improved TRANSPORT
category explanation on suggestions form Dan Wing.
</t>
<t>
Grouped all the rtcp-fb attribute analysis under a single section
as suggested by Magnus/
</t>
</list>
</t>
<t>Changes from draft-nandakumar-mmusic-mux-attributes-03
<list style="symbols">
<t> Maintenance change to clean up grammatical nits and wordings.
</t>
</list>
</t>
<t>Changes from draft-nandakumar-mmusic-mux-attributes-02
<list style="symbols">
<t>Updated Sections 5.3,5.5,5.6,5.7,5.9,5.8,5.11,5.13,5.22,5.34,
5.37,5.40,5.41,5.42,5.43,5.44,5.45,6.1,6.2,6.3,8,3,12.1 based on the
inputs from the respective RFC Authors.
</t>
</list>
</t>
<t>Changes from draft-nandakumar-mmusic-mux-attributes-01
<list style="symbols">
<t>Replaced Category BAD with NOT RECOMMENDED.</t>
<t>Added Category TBD.</t>
<t>Updated IANA Consideration Section.</t>
</list>
</t>
<t>Changes from draft-nandakumar-mmusic-mux-attributes-00
<list style="symbols">
<t>Added new section for dealing with FEC payload types.</t>
</list>
</t>
</section>
</middle>
<back>
<references title="Normative References">
&RFC4566;
<reference anchor="RFC2119">
<front>
<title abbrev="RFC Key Words">Key words for use in RFCs to Indicate
Requirement Levels</title>
<author fullname="Scott Bradner" initials="S." surname="Bradner">
<organization>Harvard University</organization>
<address>
<postal>
<street>1350 Mass. Ave.</street>
<street>Cambridge</street>
<street>MA 02138</street>
</postal>
<phone>- +1 617 495 3864</phone>
<email>sob@harvard.edu</email>
</address>
</author>
<date month="March" year="1997" />
<area>General</area>
<keyword>keyword</keyword>
</front>
<seriesInfo name="BCP" value="14" />
<seriesInfo name="RFC" value="2119" />
<format octets="4723"
target="http://www.rfc-editor.org/rfc/rfc2119.txt" type="TXT" />
<format octets="17491"
target="http://xml.resource.org/public/rfc/html/rfc2119.html"
type="HTML" />
<format octets="5777"
target="http://xml.resource.org/public/rfc/xml/rfc2119.xml"
type="XML" />
</reference>
</references>
<references title="Informative References">
&RFC3108;
&RFC3264;
&RFC3312;
&RFC3407;
&RFC3524;
&RFC3556;
&RFC3605;
&RFC3611;
&RFC3890;
&RFC4091;
&RFC4145;
&RFC4567;
&RFC4568;
&RFC4570;
&RFC4572;
&RFC4574;
&RFC4583;
&RFC4585;
&RFC4796;
&RFC4975;
&RFC5104;
&RFC5109;
&RFC5159;
&RFC5245;
&RFC5285;
&RFC5432;
&RFC5506;
&RFC5547;
&RFC5576;
&RFC5583;
&RFC5760;
&RFC5761;
&RFC5762;
&RFC5763;
&RFC5888;
&RFC5939;
&RFC5956;
&RFC6064;
&RFC6128;
&RFC6189;
&RFC6193;
&RFC6230;
&RFC6236;
&RFC6284;
&RFC6285;
&RFC6364;
&RFC6489;
&RFC6642;
&RFC6679;
&RFC6714;
&RFC6773;
&RFC6787;
&RFC6871;
&RFC6947;
&RFC7006;
&RFC7104;
&RFC7195;
&RFC7197;
&RFC7272;
&RFC7273;
&RFC7226;
&I-D.ietf-mmusic-sdp-bundle-negotiation;
<reference anchor='IANA'
target="http://www.iana.org/assignments/sdp-parameters/sdp-parameters.xml">
<front>
<title>S Description Protocol (SDP) Parameters</title>
<author/>
<date/>
</front>
</reference>
<reference anchor='T.38' target="http://www.itu.int/rec/T-REC-T.38/e">
<front>
<title>Procedures for real-time Group 3 facsimile communication over IP networks</title>
<author/>
<date/>
</front>
</reference>
<reference anchor='H.248.15' target="http://www.itu.int/rec/T-REC-H.248.15">
<front>
<title> Gateway control protocol: SDP H.248 package attribute</title>
<author/>
<date/>
</front>
</reference>
<reference anchor='ITU-T-REC.Q1970'
target="https://www.itu.int/rec/T-REC-Q.1970-200609-I/en">
<front>
<title> Q.1970 : BICC IP bearer control protocol</title>
<author/>
<date/>
</front>
</reference>
<reference anchor='R3GPPTS26.114'
target="http://www.in2eps.com/3g26/tk-3gpp-26-114.html">
<front>
<title>IP multimedia Subsystem : Media Handling and interaction</title>
<author/>
<date/>
</front>
</reference>
<reference anchor='R3GPPTS24.229'
target="http://www.3gpp.org/ftp/Specs/html-info/24229.htm">
<front>
<title>IP multimedia call control protocol based on
Session Initiation Protocol (SIP)
and Session Description Protocol (SDP);</title>
<author/>
<date/>
</front>
</reference>
<reference anchor='R3GPPTS24.182'
target="http://www.3gpp.org/ftp/Specs/html-info/24182.htm">
<front>
<title>IP Multimedia Subsystem (IMS) Customized Alerting Tones (CAT);
Protocol specification</title>
<author/>
<date/>
</front>
</reference>
<reference anchor='R3GPPTS24.183'
target="http://www.3gpp.org/ftp/Specs/html-info/24183.htm">
<front>
<title>IP Multimedia Subsystem (IMS) Customized Ringing Signal (CRS);
Protocol specification</title>
<author/>
<date/>
</front>
</reference>
<reference anchor="I.D-draft-ietf-dart-dscp-rtp">
<front>
<title>The Session Description Protocol (SDP) Content Attribute</title>
<author fullname="David Black" initials="D." surname="Black">
<organization></organization>
</author>
<author fullname="Paul Jones" initials="P." surname="Jones">
<organization></organization>
</author>
<date month="September" year="2014" />
</front>
<seriesInfo name='Internet-Draft' value='draft-ietf-dart-dscp-rtp-07' />
<format type='TXT'
target='http://www.ietf.org/id/draft-ietf-dart-dscp-rtp-07.txt' />
</reference>
</references>
</back>
</rfc>
| PAFTECH AB 2003-2026 | 2026-04-23 09:30:25 |