rfc8859v4.txt   rfc8859.txt 
Internet Engineering Task Force (IETF) S. Nandakumar Internet Engineering Task Force (IETF) S. Nandakumar
Request for Comments: 8859 Cisco Request for Comments: 8859 Cisco
Category: Standards Track May 2020 Category: Standards Track August 2020
ISSN: 2070-1721 ISSN: 2070-1721
A Framework for Session Description Protocol (SDP) Attributes When A Framework for Session Description Protocol (SDP) Attributes When
Multiplexing Multiplexing
Abstract Abstract
The purpose of this specification is to provide a framework for The purpose of this specification is to provide a framework for
analyzing the multiplexing characteristics of Session Description analyzing the multiplexing characteristics of Session Description
Protocol (SDP) attributes when SDP is used to negotiate the usage of Protocol (SDP) attributes when SDP is used to negotiate the usage of
skipping to change at line 118 skipping to change at line 118
5.42. RFC 7195: SDP Extension for Circuit-Switched Bearers in 5.42. RFC 7195: SDP Extension for Circuit-Switched Bearers in
PSTN PSTN
5.43. RFC 7272: IDMS Using the RTP Control Protocol (RTCP) 5.43. RFC 7272: IDMS Using the RTP Control Protocol (RTCP)
5.44. RFC 5159: Open Mobile Alliance (OMA) Broadcast (BCAST) SDP 5.44. RFC 5159: Open Mobile Alliance (OMA) Broadcast (BCAST) SDP
Attributes Attributes
5.45. RFC 6193: Media Description for IKE in SDP 5.45. RFC 6193: Media Description for IKE in SDP
5.46. RFC 2326: Real Time Streaming Protocol 5.46. RFC 2326: Real Time Streaming Protocol
5.47. RFC 6064: SDP and RTSP Extensions for 3GPP 5.47. RFC 6064: SDP and RTSP Extensions for 3GPP
5.48. RFC 3108: ATM SDP 5.48. RFC 3108: ATM SDP
5.49. 3GPP TS 183.063 5.49. 3GPP TS 183.063
5.50. 3GPP TS 24.182 5.50. 3GPP TS 24.229
5.51. 3GPP TS 24.183 5.51. ITU T.38
5.52. 3GPP TS 24.229 5.52. ITU-T Q.1970
5.53. ITU T.38 5.53. ITU-T H.248.15
5.54. ITU-T Q.1970 5.54. RFC 4975: The Message Session Relay Protocol
5.55. ITU-T H.248.15 5.55. Historical Attributes
5.56. RFC 4975: The Message Session Relay Protocol
5.57. Historical Attributes
6. bwtype Attribute Analysis 6. bwtype Attribute Analysis
6.1. RFC 4566: SDP 6.1. RFC 4566: SDP
6.2. RFC 3556: SDP Bandwidth Modifiers for RTCP Bandwidth 6.2. RFC 3556: SDP Bandwidth Modifiers for RTCP Bandwidth
6.3. RFC 3890: Bandwidth Modifier for SDP 6.3. RFC 3890: Bandwidth Modifier for SDP
7. rtcp-fb Attribute Analysis 7. rtcp-fb Attribute Analysis
7.1. RFC 4585: RTP/AVPF 7.1. RFC 4585: RTP/AVPF
7.2. RFC 5104: Codec Control Messages in AVPF 7.2. RFC 5104: Codec Control Messages in AVPF
7.3. RFC 6285: Unicast-Based Rapid Acquisition of Multicast RTP 7.3. RFC 6285: Unicast-Based Rapid Acquisition of Multicast RTP
Sessions (RAMS) Sessions (RAMS)
7.4. RFC 6679: ECN for RTP over UDP/IP 7.4. RFC 6679: ECN for RTP over UDP/IP
skipping to change at line 155 skipping to change at line 153
8.6. RFC 7104: Duplication Grouping Semantics in the SDP 8.6. RFC 7104: Duplication Grouping Semantics in the SDP
9. ssrc-group Attribute Analysis 9. ssrc-group Attribute Analysis
9.1. RFC 5576: Source-Specific SDP Attributes 9.1. RFC 5576: Source-Specific SDP Attributes
9.2. RFC 7104: Duplication Grouping Semantics in the SDP 9.2. RFC 7104: Duplication Grouping Semantics in the SDP
10. QoS Mechanism Token Analysis 10. QoS Mechanism Token Analysis
10.1. RFC 5432: QoS Mechanism Selection in SDP 10.1. RFC 5432: QoS Mechanism Selection in SDP
11. k= Attribute Analysis 11. k= Attribute Analysis
11.1. RFC 4566: SDP 11.1. RFC 4566: SDP
12. content Attribute Analysis 12. content Attribute Analysis
12.1. RFC 4796 12.1. RFC 4796
12.2. 3GPP TS 24.182
12.3. 3GPP TS 24.183
13. Payload Formats 13. Payload Formats
13.1. RFC 5109: RTP Payload Format for Generic FEC 13.1. RFC 5109: RTP Payload Format for Generic FEC
14. Multiplexing Considerations for Encapsulating Attributes 14. Multiplexing Considerations for Encapsulating Attributes
14.1. RFC 3407: cpar Attribute Analysis 14.1. RFC 3407: cpar Attribute Analysis
14.2. RFC 5939 Analysis 14.2. RFC 5939 Analysis
14.2.1. Recommendation: Procedures for Potential Configuration 14.2.1. Recommendation: Procedures for Potential Configuration
Pairing Pairing
14.3. RFC 6871 Analysis 14.3. RFC 6871 Analysis
14.3.1. Recommendation: Dealing with Payload Type Numbers 14.3.1. Recommendation: Dealing with Payload Type Numbers
14.3.2. Recommendation: Dealing with Latent Configurations 14.3.2. Recommendation: Dealing with Latent Configurations
15. IANA Considerations 15. IANA Considerations
15.1. New "Multiplexing Categories" Subregistry 15.1. New "Multiplexing Categories" Subregistry
15.2. "Mux Category" Column for Subregistries 15.2. "Mux Category" Column for Subregistries
15.2.1. Table: SDP bwtype 15.2.1. Table: SDP bwtype
15.2.2. Table: att-field 15.2.2. Table: attribute-name
15.2.3. Table: content SDP Parameters 15.2.3. Table: content SDP Parameters
15.2.4. Table: Semantics for the "group" SDP Attribute 15.2.4. Table: Semantics for the "group" SDP Attribute
15.2.5. Table: "rtcp-fb" Attribute Values 15.2.5. Table: "rtcp-fb" Attribute Values
15.2.6. Table: "ack" and "nack" Attribute Values 15.2.6. Table: "ack" and "nack" Attribute Values
15.2.7. Table: "depend" SDP Attribute Values 15.2.7. Table: "depend" SDP Attribute Values
15.2.8. Table: "cs-correlation" Attribute Values 15.2.8. Table: "cs-correlation" Attribute Values
15.2.9. Table: Semantics for the "ssrc-group" SDP Attribute 15.2.9. Table: Semantics for the "ssrc-group" SDP Attribute
15.2.10. Table: SDP/RTSP Key Management Protocol Identifiers 15.2.10. Table: SDP/RTSP Key Management Protocol Identifiers
15.2.11. Table: Codec Control Messages 15.2.11. Table: Codec Control Messages
15.2.12. Table: QoS Mechanism Tokens 15.2.12. Table: QoS Mechanism Tokens
skipping to change at line 1983 skipping to change at line 1983
+--------------------+--------------+-------+--------------+ +--------------------+--------------+-------+--------------+
| bc_service | Not impacted | S | NORMAL | | bc_service | Not impacted | S | NORMAL |
+--------------------+--------------+-------+--------------+ +--------------------+--------------+-------+--------------+
| bc_program | Not impacted | S | NORMAL | | bc_program | Not impacted | S | NORMAL |
+--------------------+--------------+-------+--------------+ +--------------------+--------------+-------+--------------+
| bc_service_package | Not impacted | S | NORMAL | | bc_service_package | Not impacted | S | NORMAL |
+--------------------+--------------+-------+--------------+ +--------------------+--------------+-------+--------------+
Table 49: 3GPP TS 183.063 Attribute Analysis Table 49: 3GPP TS 183.063 Attribute Analysis
5.50. 3GPP TS 24.182 5.50. 3GPP TS 24.229
[IMS-CAT] specifies an IP multimedia subsystem for customized
alerting tones.
+============+=========================+=======+==============+
| Name | Notes | Level | Mux Category |
+============+=========================+=======+==============+
| g.3gpp.cat | Usage defined for the | M | NORMAL |
| | IP multimedia subsystem | | |
+------------+-------------------------+-------+--------------+
Table 50: 3GPP TS 24.182 Attribute Analysis
5.51. 3GPP TS 24.183
[IMS-CRS] specifies an IP multimedia subsystem for customized ringing
signal.
+============+=========================+=======+==============+
| Name | Notes | Level | Mux Category |
+============+=========================+=======+==============+
| g.3gpp.crs | Usage defined for the | M | NORMAL |
| | IP multimedia subsystem | | |
+------------+-------------------------+-------+--------------+
Table 51: 3GPP TS 24.183 Attribute Analysis
5.52. 3GPP TS 24.229
[IP-CALL] specifies an IP multimedia call control protocol based on [IP-CALL] specifies an IP multimedia call control protocol based on
Session Initial protocol and Session Description Protocol. Session Initial protocol and Session Description Protocol.
+=================+============================+=======+===========+ +=================+============================+=======+===========+
| Name | Notes | Level | Mux | | Name | Notes | Level | Mux |
| | | | Category | | | | | Category |
+=================+============================+=======+===========+ +=================+============================+=======+===========+
| secondary-realm | secondary-realm MUST be | M | TRANSPORT | | secondary-realm | secondary-realm MUST be | M | TRANSPORT |
| | the one that corresponds | | | | | the one that corresponds | | |
skipping to change at line 2047 skipping to change at line 2019
+-----------------+----------------------------+-------+-----------+ +-----------------+----------------------------+-------+-----------+
| omr-s-att | Not impacted | M | NORMAL | | omr-s-att | Not impacted | M | NORMAL |
+-----------------+----------------------------+-------+-----------+ +-----------------+----------------------------+-------+-----------+
| omr-m-bw | Not impacted | M | NORMAL | | omr-m-bw | Not impacted | M | NORMAL |
+-----------------+----------------------------+-------+-----------+ +-----------------+----------------------------+-------+-----------+
| omr-s-bw | Not impacted | M | NORMAL | | omr-s-bw | Not impacted | M | NORMAL |
+-----------------+----------------------------+-------+-----------+ +-----------------+----------------------------+-------+-----------+
| omr-codecs | Not impacted | M | NORMAL | | omr-codecs | Not impacted | M | NORMAL |
+-----------------+----------------------------+-------+-----------+ +-----------------+----------------------------+-------+-----------+
Table 52: 3GPP TS 24.229 Attribute Analysis Table 50: 3GPP TS 24.229 Attribute Analysis
5.53. ITU T.38 5.51. ITU T.38
[T.38] defines procedures for real-time Group 3 facsimile [T.38] defines procedures for real-time Group 3 facsimile
communications over IP networks. communications over IP networks.
+=======================+=============+=======+==============+ +=======================+=============+=======+==============+
| Name | Notes | Level | Mux Category | | Name | Notes | Level | Mux Category |
+=======================+=============+=======+==============+ +=======================+=============+=======+==============+
| T38FaxVersion | Refer to | M | TBD | | T38FaxVersion | Refer to | M | TBD |
| | notes below | | | | | notes below | | |
+-----------------------+-------------+-------+--------------+ +-----------------------+-------------+-------+--------------+
skipping to change at line 2100 skipping to change at line 2072
| T38FaxUdpFECMaxSpan | Refer to | M | TBD | | T38FaxUdpFECMaxSpan | Refer to | M | TBD |
| | notes below | | | | | notes below | | |
+-----------------------+-------------+-------+--------------+ +-----------------------+-------------+-------+--------------+
| T38ModemType | Refer to | M | TBD | | T38ModemType | Refer to | M | TBD |
| | notes below | | | | | notes below | | |
+-----------------------+-------------+-------+--------------+ +-----------------------+-------------+-------+--------------+
| T38VendorInfo | Refer to | M | TBD | | T38VendorInfo | Refer to | M | TBD |
| | notes below | | | | | notes below | | |
+-----------------------+-------------+-------+--------------+ +-----------------------+-------------+-------+--------------+
Table 53: ITU T.38 Attribute Analysis Table 51: ITU T.38 Attribute Analysis
NOTE: As per Section 9 of [RFC8843], there exists no publicly NOTE: As per Section 9 of [RFC8843], there exists no publicly
available specification that defines procedures for multiplexing/ available specification that defines procedures for multiplexing/
demultiplexing fax protocol flows over a single 5-tuple. Once such a demultiplexing fax protocol flows over a single 5-tuple. Once such a
specification is available, the multiplexing category assignments for specification is available, the multiplexing category assignments for
the attributes in this section could be revisited. the attributes in this section could be revisited.
5.54. ITU-T Q.1970 5.52. ITU-T Q.1970
[Q.1970] defines Bearer Independent Call Control (BICC) IP bearer [Q.1970] defines Bearer Independent Call Control (BICC) IP bearer
control protocol. control protocol.
+=======+=====================================+=======+==========+ +=======+=====================================+=======+==========+
| Name | Notes | Level | Mux | | Name | Notes | Level | Mux |
| | | | Category | | | | | Category |
+=======+=====================================+=======+==========+ +=======+=====================================+=======+==========+
| ipbcp | ipbcp version identifies the types | S | SPECIAL | | ipbcp | ipbcp version identifies the types | S | SPECIAL |
| | of IP bearer control protocol | | | | | of IP bearer control protocol | | |
| | (IPBCP) message used in BICC (ITU-T | | | | | (IPBCP) message used in BICC (ITU-T | | |
| | Q.1901) environment that are | | | | | Q.1901) environment that are | | |
| | limited to single-media payload. | | | | | limited to single-media payload. | | |
| | Refer to the pertinent ITU-T | | | | | Refer to the pertinent ITU-T | | |
| | specifications while multiplexing. | | | | | specifications while multiplexing. | | |
+-------+-------------------------------------+-------+----------+ +-------+-------------------------------------+-------+----------+
Table 54: ITU-T Q.1970 Attribute Analysis Table 52: ITU-T Q.1970 Attribute Analysis
5.55. ITU-T H.248.15 5.53. ITU-T H.248.15
ITU-T H.248.15 [H.248.15] defines the Gateway Control Protocol SDP ITU-T H.248.15 [H.248.15] defines the Gateway Control Protocol SDP
H.248 package attribute. H.248 package attribute.
+==========+=====================================+=======+==========+ +==========+=====================================+=======+==========+
| Name | Notes | Level | Mux | | Name | Notes | Level | Mux |
| | | | Category | | | | | Category |
+==========+=====================================+=======+==========+ +==========+=====================================+=======+==========+
| h248item | It is only applicable for | B | SPECIAL | | h248item | It is only applicable for | B | SPECIAL |
| | signaling the inclusion of H.248 | | | | | signaling the inclusion of H.248 | | |
skipping to change at line 2158 skipping to change at line 2130
| | is an issue. This is only a | | | | | is an issue. This is only a | | |
| | concern in environments using a | | | | | concern in environments using a | | |
| | decomposed server/gateway with | | | | | decomposed server/gateway with | | |
| | H.248 signaled between them. The | | | | | H.248 signaled between them. The | | |
| | ITU-T will need to do further | | | | | ITU-T will need to do further | | |
| | analysis of various packages when | | | | | analysis of various packages when | | |
| | they specify how to signal the | | | | | they specify how to signal the | | |
| | use of multiplexing to a gateway. | | | | | use of multiplexing to a gateway. | | |
+----------+-------------------------------------+-------+----------+ +----------+-------------------------------------+-------+----------+
Table 55: ITU-T H.248.15 Attribute Analysis Table 53: ITU-T H.248.15 Attribute Analysis
5.56. RFC 4975: The Message Session Relay Protocol 5.54. RFC 4975: The Message Session Relay Protocol
[RFC4975] describes the Message Session Relay Protocol, a protocol [RFC4975] describes the Message Session Relay Protocol, a protocol
for transmitting a series of related instant messages in the context for transmitting a series of related instant messages in the context
of a session. Message sessions are treated like any other media of a session. Message sessions are treated like any other media
stream when set up via a rendezvous or session-creation protocol such stream when set up via a rendezvous or session-creation protocol such
as the Session Initiation Protocol. as the Session Initiation Protocol.
+======================+=============+=======+==============+ +======================+=============+=======+==============+
| Name | Notes | Level | Mux Category | | Name | Notes | Level | Mux Category |
+======================+=============+=======+==============+ +======================+=============+=======+==============+
skipping to change at line 2184 skipping to change at line 2156
| accept-wrapped-types | Refer to | M | TBD | | accept-wrapped-types | Refer to | M | TBD |
| | notes below | | | | | notes below | | |
+----------------------+-------------+-------+--------------+ +----------------------+-------------+-------+--------------+
| max-size | Refer to | M | TBD | | max-size | Refer to | M | TBD |
| | notes below | | | | | notes below | | |
+----------------------+-------------+-------+--------------+ +----------------------+-------------+-------+--------------+
| path | Refer to | M | TBD | | path | Refer to | M | TBD |
| | notes below | | | | | notes below | | |
+----------------------+-------------+-------+--------------+ +----------------------+-------------+-------+--------------+
Table 56: RFC 4975 Attribute Analysis Table 54: RFC 4975 Attribute Analysis
NOTE: As per Section 9 of [RFC8843], there exists no publicly NOTE: As per Section 9 of [RFC8843], there exists no publicly
available specification that defines procedures for multiplexing/ available specification that defines procedures for multiplexing/
demultiplexing MSRP flows over a single 5-tuple. Once such a demultiplexing MSRP flows over a single 5-tuple. Once such a
specification is available, the multiplexing categories assignments specification is available, the multiplexing categories assignments
for the attributes in this section could be revisited. for the attributes in this section could be revisited.
5.57. Historical Attributes 5.55. Historical Attributes
This section specifies analysis for the attributes that are included This section specifies analysis for the attributes that are included
for historic usage alone by the [IANA]. for historic usage alone by the [IANA].
+=========+=====================+=======+==============+ +=========+=====================+=======+==============+
| Name | Notes | Level | Mux Category | | Name | Notes | Level | Mux Category |
+=========+=====================+=======+==============+ +=========+=====================+=======+==============+
| rtpred1 | Historic attributes | M | CAUTION | | rtpred1 | Historic attributes | M | CAUTION |
+---------+---------------------+-------+--------------+ +---------+---------------------+-------+--------------+
| rtpred2 | Historic attributes | M | CAUTION | | rtpred2 | Historic attributes | M | CAUTION |
+---------+---------------------+-------+--------------+ +---------+---------------------+-------+--------------+
Table 57: Historical Attribute Analysis Table 55: Historical Attribute Analysis
6. bwtype Attribute Analysis 6. bwtype Attribute Analysis
This section specifies handling of specific bandwidth attributes when This section specifies handling of specific bandwidth attributes when
used in multiplexing scenarios. used in multiplexing scenarios.
6.1. RFC 4566: SDP 6.1. RFC 4566: SDP
[RFC4566] defines SDP that is intended for describing multimedia [RFC4566] defines SDP that is intended for describing multimedia
sessions for the purposes of session announcement, session sessions for the purposes of session announcement, session
skipping to change at line 2229 skipping to change at line 2201
| Name | Notes | Level | Mux | | Name | Notes | Level | Mux |
| | | | Category | | | | | Category |
+===========+=================================+=======+==========+ +===========+=================================+=======+==========+
| bwtype:CT | Not impacted | S | NORMAL | | bwtype:CT | Not impacted | S | NORMAL |
+-----------+---------------------------------+-------+----------+ +-----------+---------------------------------+-------+----------+
| bwtype:AS | For media-level usage, the | B | SUM | | bwtype:AS | For media-level usage, the | B | SUM |
| | aggregate of individual | | | | | aggregate of individual | | |
| | bandwidth values is considered. | | | | | bandwidth values is considered. | | |
+-----------+---------------------------------+-------+----------+ +-----------+---------------------------------+-------+----------+
Table 58: RFC 4566 bwtype Analysis Table 56: RFC 4566 bwtype Analysis
6.2. RFC 3556: SDP Bandwidth Modifiers for RTCP Bandwidth 6.2. RFC 3556: SDP Bandwidth Modifiers for RTCP Bandwidth
[RFC3556] defines an extension to SDP to specify two additional [RFC3556] defines an extension to SDP to specify two additional
modifiers for the bandwidth attribute. These modifiers may be used modifiers for the bandwidth attribute. These modifiers may be used
to specify the bandwidth allowed for RTCP packets in an RTP session. to specify the bandwidth allowed for RTCP packets in an RTP session.
+===========+================================+=======+==========+ +===========+================================+=======+==========+
| Name | Notes | Level | Mux | | Name | Notes | Level | Mux |
| | | | Category | | | | | Category |
skipping to change at line 2254 skipping to change at line 2226
| | the individual values while | | | | | the individual values while | | |
| | multiplexing. | | | | | multiplexing. | | |
+-----------+--------------------------------+-------+----------+ +-----------+--------------------------------+-------+----------+
| bwtype:RR | Session-level usage represents | B | SUM | | bwtype:RR | Session-level usage represents | B | SUM |
| | session aggregate, and media- | | | | | session aggregate, and media- | | |
| | level usage indicates SUM of | | | | | level usage indicates SUM of | | |
| | the individual values while | | | | | the individual values while | | |
| | multiplexing. | | | | | multiplexing. | | |
+-----------+--------------------------------+-------+----------+ +-----------+--------------------------------+-------+----------+
Table 59: RFC 3556 bwtype Analysis Table 57: RFC 3556 bwtype Analysis
6.3. RFC 3890: Bandwidth Modifier for SDP 6.3. RFC 3890: Bandwidth Modifier for SDP
[RFC3890] defines SDP Transport Independent Application Specific [RFC3890] defines SDP Transport Independent Application Specific
Maximum (TIAS) bandwidth modifier that does not include transport Maximum (TIAS) bandwidth modifier that does not include transport
overhead; instead, an additional packet-rate attribute is defined. overhead; instead, an additional packet-rate attribute is defined.
The transport-independent bitrate value together with the maximum The transport-independent bitrate value together with the maximum
packet rate can then be used to calculate the real bitrate over the packet rate can then be used to calculate the real bitrate over the
transport actually used. transport actually used.
skipping to change at line 2278 skipping to change at line 2250
+=============+==================================+=======+==========+ +=============+==================================+=======+==========+
| bwtype:TIAS | The usage of TIAS is not | B | SPECIAL | | bwtype:TIAS | The usage of TIAS is not | B | SPECIAL |
| | defined under offer/answer | | | | | defined under offer/answer | | |
| | usage. | | | | | usage. | | |
+-------------+----------------------------------+-------+----------+ +-------------+----------------------------------+-------+----------+
| maxprate | The usage of TIAS and | B | SPECIAL | | maxprate | The usage of TIAS and | B | SPECIAL |
| | maxprate is not well | | | | | maxprate is not well | | |
| | defined under multiplexing. | | | | | defined under multiplexing. | | |
+-------------+----------------------------------+-------+----------+ +-------------+----------------------------------+-------+----------+
Table 60: RFC 3890 bwtype Analysis Table 58: RFC 3890 bwtype Analysis
NOTE: The intention of TIAS is that the media-level bitrate is NOTE: The intention of TIAS is that the media-level bitrate is
multiplied with the known per-packet overhead for the selected multiplied with the known per-packet overhead for the selected
transport and the maxprate value to determine the worst-case bitrate transport and the maxprate value to determine the worst-case bitrate
from the transport to more accurately capture the required usage. from the transport to more accurately capture the required usage.
Summing TIAS values independently across "m=" lines and multiplying Summing TIAS values independently across "m=" lines and multiplying
the computed sum with maxprate and the per-packet overhead would the computed sum with maxprate and the per-packet overhead would
inflate the value significantly. Instead, performing multiplication inflate the value significantly. Instead, performing multiplication
and adding the individual values is a more appropriate usage. and adding the individual values is a more appropriate usage.
skipping to change at line 2336 skipping to change at line 2308
+---------+-----------------------------+-------+------------------+ +---------+-----------------------------+-------+------------------+
| nack | Feedback parameters MUST be | M | SPECIAL | | nack | Feedback parameters MUST be | M | SPECIAL |
| app | handled in the app specific | | | | app | handled in the app specific | | |
| | way when multiplexed. | | | | | way when multiplexed. | | |
+---------+-----------------------------+-------+------------------+ +---------+-----------------------------+-------+------------------+
| trr-int | The attribute value MUST be | M | IDENTICAL-PER-PT | | trr-int | The attribute value MUST be | M | IDENTICAL-PER-PT |
| | the same for a given codec | | | | | the same for a given codec | | |
| | configuration. | | | | | configuration. | | |
+---------+-----------------------------+-------+------------------+ +---------+-----------------------------+-------+------------------+
Table 61: RFC 4585 Attribute Analysis Table 59: RFC 4585 Attribute Analysis
7.2. RFC 5104: Codec Control Messages in AVPF 7.2. RFC 5104: Codec Control Messages in AVPF
[RFC5104] specifies a few extensions to the messages defined in the [RFC5104] specifies a few extensions to the messages defined in the
Audio-Visual Profile with Feedback (AVPF). They are helpful Audio-Visual Profile with Feedback (AVPF). They are helpful
primarily in conversational multimedia scenarios where centralized primarily in conversational multimedia scenarios where centralized
multipoint functionalities are in use. However, some are also usable multipoint functionalities are in use. However, some are also usable
in smaller multicast environments and point-to-point calls. in smaller multicast environments and point-to-point calls.
+======+==========================+=======+==================+ +======+==========================+=======+==================+
| Name | Notes | Level | Mux Category | | Name | Notes | Level | Mux Category |
+======+==========================+=======+==================+ +======+==========================+=======+==================+
| ccm | The attribute value MUST | M | IDENTICAL-PER-PT | | ccm | The attribute value MUST | M | IDENTICAL-PER-PT |
| | be the same for a given | | | | | be the same for a given | | |
| | codec configuration. | | | | | codec configuration. | | |
+------+--------------------------+-------+------------------+ +------+--------------------------+-------+------------------+
Table 62: RFC 5104 Attribute Analysis Table 60: RFC 5104 Attribute Analysis
7.3. RFC 6285: Unicast-Based Rapid Acquisition of Multicast RTP 7.3. RFC 6285: Unicast-Based Rapid Acquisition of Multicast RTP
Sessions (RAMS) Sessions (RAMS)
[RFC6285] describes a method of using the existing RTP and RTCP [RFC6285] describes a method of using the existing RTP and RTCP
machinery that reduces the acquisition delay. In this method, an machinery that reduces the acquisition delay. In this method, an
auxiliary unicast RTP session carrying the Reference Information to auxiliary unicast RTP session carrying the Reference Information to
the receiver precedes or accompanies the multicast stream. This the receiver precedes or accompanies the multicast stream. This
unicast RTP flow can be transmitted at a faster-than-natural bitrate unicast RTP flow can be transmitted at a faster-than-natural bitrate
to further accelerate the acquisition. The motivating use case for to further accelerate the acquisition. The motivating use case for
skipping to change at line 2376 skipping to change at line 2348
compressed audio and video. compressed audio and video.
+======+==========================+=======+==================+ +======+==========================+=======+==================+
| Name | Notes | Level | Mux Category | | Name | Notes | Level | Mux Category |
+======+==========================+=======+==================+ +======+==========================+=======+==================+
| nack | The attribute value MUST | M | IDENTICAL-PER-PT | | nack | The attribute value MUST | M | IDENTICAL-PER-PT |
| rai | be the same for a given | | | | rai | be the same for a given | | |
| | codec configuration. | | | | | codec configuration. | | |
+------+--------------------------+-------+------------------+ +------+--------------------------+-------+------------------+
Table 63: RFC 6285 Attribute Analysis Table 61: RFC 6285 Attribute Analysis
7.4. RFC 6679: ECN for RTP over UDP/IP 7.4. RFC 6679: ECN for RTP over UDP/IP
[RFC6679] specifies how Explicit Congestion Notification (ECN) can be [RFC6679] specifies how Explicit Congestion Notification (ECN) can be
used with the RTP running over UDP, using the RTCP as a feedback used with the RTP running over UDP, using the RTCP as a feedback
mechanism. It defines a new RTCP Extended Report (XR) block for mechanism. It defines a new RTCP Extended Report (XR) block for
periodic ECN feedback, a new RTCP transport feedback message for periodic ECN feedback, a new RTCP transport feedback message for
timely reporting of congestion events, and a STUN extension used in timely reporting of congestion events, and a STUN extension used in
the optional initialization method using ICE. the optional initialization method using ICE.
skipping to change at line 2398 skipping to change at line 2370
| Name | Notes | Level | Mux | | Name | Notes | Level | Mux |
| | | | Category | | | | | Category |
+=================+============================+=======+===========+ +=================+============================+=======+===========+
| ecn-capable-rtp | ECN markup is enabled at | M | IDENTICAL | | ecn-capable-rtp | ECN markup is enabled at | M | IDENTICAL |
| | the RTP session level. | | | | | the RTP session level. | | |
+-----------------+----------------------------+-------+-----------+ +-----------------+----------------------------+-------+-----------+
| nack ecn | This attribute enables ECN | M | IDENTICAL | | nack ecn | This attribute enables ECN | M | IDENTICAL |
| | at the RTP session level. | | | | | at the RTP session level. | | |
+-----------------+----------------------------+-------+-----------+ +-----------------+----------------------------+-------+-----------+
Table 64: RFC 6679 Attribute Analysis Table 62: RFC 6679 Attribute Analysis
7.5. RFC 6642: Third-Party Loss Report 7.5. RFC 6642: Third-Party Loss Report
In a large RTP session using the RTCP feedback mechanism defined in In a large RTP session using the RTCP feedback mechanism defined in
[RFC4585], a feedback target may experience transient overload if [RFC4585], a feedback target may experience transient overload if
some event causes a large number of receivers to send feedback at some event causes a large number of receivers to send feedback at
once. This overload is usually avoided by ensuring that feedback once. This overload is usually avoided by ensuring that feedback
reports are forwarded to all receivers, allowing them to avoid reports are forwarded to all receivers, allowing them to avoid
sending duplicate feedback reports. However, there are cases where sending duplicate feedback reports. However, there are cases where
it is not recommended to forward feedback reports, and this may allow it is not recommended to forward feedback reports, and this may allow
skipping to change at line 2426 skipping to change at line 2398
+=======+==========================+=======+==================+ +=======+==========================+=======+==================+
| nack | The attribute value MUST | M | IDENTICAL-PER-PT | | nack | The attribute value MUST | M | IDENTICAL-PER-PT |
| tllei | be the same for a given | | | | tllei | be the same for a given | | |
| | codec configuration. | | | | | codec configuration. | | |
+-------+--------------------------+-------+------------------+ +-------+--------------------------+-------+------------------+
| nack | The attribute value MUST | M | IDENTICAL-PER-PT | | nack | The attribute value MUST | M | IDENTICAL-PER-PT |
| pslei | be the same for a given | | | | pslei | be the same for a given | | |
| | codec configuration. | | | | | codec configuration. | | |
+-------+--------------------------+-------+------------------+ +-------+--------------------------+-------+------------------+
Table 65: RFC 6642 Attribute Analysis Table 63: RFC 6642 Attribute Analysis
7.6. RFC 5104: Codec Control Messages in AVPF 7.6. RFC 5104: Codec Control Messages in AVPF
[RFC5104] specifies a few extensions to the messages defined in the [RFC5104] specifies a few extensions to the messages defined in the
Audio-Visual Profile with Feedback (AVPF). They are helpful Audio-Visual Profile with Feedback (AVPF). They are helpful
primarily in conversational multimedia scenarios where centralized primarily in conversational multimedia scenarios where centralized
multipoint functionalities are in use. However, some are also usable multipoint functionalities are in use. However, some are also usable
in smaller multicast environments and point-to-point calls. in smaller multicast environments and point-to-point calls.
+=======+==========================+=======+==================+ +=======+==========================+=======+==================+
skipping to change at line 2456 skipping to change at line 2428
+-------+--------------------------+-------+------------------+ +-------+--------------------------+-------+------------------+
| ccm | The attribute value MUST | M | IDENTICAL-PER-PT | | ccm | The attribute value MUST | M | IDENTICAL-PER-PT |
| tstr | be the same for a given | | | | tstr | be the same for a given | | |
| | codec configuration. | | | | | codec configuration. | | |
+-------+--------------------------+-------+------------------+ +-------+--------------------------+-------+------------------+
| ccm | The attribute value MUST | M | IDENTICAL-PER-PT | | ccm | The attribute value MUST | M | IDENTICAL-PER-PT |
| vbcm | be the same for a given | | | | vbcm | be the same for a given | | |
| | codec configuration. | | | | | codec configuration. | | |
+-------+--------------------------+-------+------------------+ +-------+--------------------------+-------+------------------+
Table 66: RFC 5104 Attribute Analysis Table 64: RFC 5104 Attribute Analysis
8. group Attribute Analysis 8. group Attribute Analysis
This section analyzes SDP "group" attribute semantics [RFC5888]. This section analyzes SDP "group" attribute semantics [RFC5888].
8.1. RFC 5888: SDP Grouping Framework 8.1. RFC 5888: SDP Grouping Framework
[RFC5888] defines a framework to group "m=" lines in SDP for [RFC5888] defines a framework to group "m=" lines in SDP for
different purposes. different purposes.
+===========+==============+=======+==============+ +===========+==============+=======+==============+
| Name | Notes | Level | Mux Category | | Name | Notes | Level | Mux Category |
+===========+==============+=======+==============+ +===========+==============+=======+==============+
| group:LS | Not impacted | S | NORMAL | | group:LS | Not impacted | S | NORMAL |
+-----------+--------------+-------+--------------+ +-----------+--------------+-------+--------------+
| group:FID | Not impacted | S | NORMAL | | group:FID | Not impacted | S | NORMAL |
+-----------+--------------+-------+--------------+ +-----------+--------------+-------+--------------+
Table 67: RFC 5888 Attribute Analysis Table 65: RFC 5888 Attribute Analysis
8.2. RFC 3524: Mapping Media Streams to Resource Reservation Flows 8.2. RFC 3524: Mapping Media Streams to Resource Reservation Flows
[RFC3524] defines an extension to the SDP grouping framework. It [RFC3524] defines an extension to the SDP grouping framework. It
allows requesting a group of media streams to be mapped into a single allows requesting a group of media streams to be mapped into a single
resource reservation flow. The SDP syntax needed is defined, as well resource reservation flow. The SDP syntax needed is defined, as well
as a new "semantics" attribute called Single Reservation Flow (SRF). as a new "semantics" attribute called Single Reservation Flow (SRF).
+===========+==============+=======+==============+ +===========+==============+=======+==============+
| Name | Notes | Level | Mux Category | | Name | Notes | Level | Mux Category |
+===========+==============+=======+==============+ +===========+==============+=======+==============+
| group:SRF | Not impacted | S | NORMAL | | group:SRF | Not impacted | S | NORMAL |
+-----------+--------------+-------+--------------+ +-----------+--------------+-------+--------------+
Table 68: RFC 3524 Attribute Analysis Table 66: RFC 3524 Attribute Analysis
8.3. RFC 4091: ANAT Semantics 8.3. RFC 4091: ANAT Semantics
[RFC4091] defines ANAT semantics for the SDP grouping framework. [RFC4091] defines ANAT semantics for the SDP grouping framework.
(Note: [RFC4091] has been obsoleted by [RFC8445].) The ANAT (Note: [RFC4091] has been obsoleted by [RFC8445].) The ANAT
semantics allow alternative types of network addresses to establish a semantics allow alternative types of network addresses to establish a
particular media stream. particular media stream.
+============+==============================+=======+==============+ +============+==============================+=======+==============+
| Name | Notes | Level | Mux Category | | Name | Notes | Level | Mux Category |
+============+==============================+=======+==============+ +============+==============================+=======+==============+
| group:ANAT | ANAT semantics is obsoleted. | S | CAUTION | | group:ANAT | ANAT semantics is obsoleted. | S | CAUTION |
+------------+------------------------------+-------+--------------+ +------------+------------------------------+-------+--------------+
Table 69: RFC 4091 Attribute Analysis Table 67: RFC 4091 Attribute Analysis
8.4. RFC 5956: FEC Grouping Semantics in SDP 8.4. RFC 5956: FEC Grouping Semantics in SDP
[RFC5956] defines the semantics for grouping the associated source [RFC5956] defines the semantics for grouping the associated source
and FEC-based repair flows in SDP. The semantics defined in the and FEC-based repair flows in SDP. The semantics defined in the
document are to be used with the SDP Grouping Framework [RFC5888]. document are to be used with the SDP Grouping Framework [RFC5888].
These semantics allow the description of grouping relationships These semantics allow the description of grouping relationships
between the source and repair flows when one or more source and/or between the source and repair flows when one or more source and/or
repair flows are associated in the same group; they also provide repair flows are associated in the same group; they also provide
support for additive repair flows. SSRC-level grouping semantics are support for additive repair flows. SSRC-level grouping semantics are
also defined in this document for RTP streams using SSRC also defined in this document for RTP streams using SSRC
multiplexing. multiplexing.
+==============+==============+=======+==============+ +==============+==============+=======+==============+
| Name | Notes | Level | Mux Category | | Name | Notes | Level | Mux Category |
+==============+==============+=======+==============+ +==============+==============+=======+==============+
| group:FEC-FR | Not impacted | S | NORMAL | | group:FEC-FR | Not impacted | S | NORMAL |
+--------------+--------------+-------+--------------+ +--------------+--------------+-------+--------------+
Table 70: RFC 5956 Attribute Analysis Table 68: RFC 5956 Attribute Analysis
8.5. RFC 5583: Signaling Media Decoding Dependency in SDP 8.5. RFC 5583: Signaling Media Decoding Dependency in SDP
[RFC5583] defines semantics that allow for signaling the decoding [RFC5583] defines semantics that allow for signaling the decoding
dependency of different media descriptions with the same media type dependency of different media descriptions with the same media type
in SDP. This is required, for example, if media data is separated in SDP. This is required, for example, if media data is separated
and transported in different network streams as a result of using a and transported in different network streams as a result of using a
layered or multiple descriptive media coding process. layered or multiple descriptive media coding process.
+===========+==========================+=======+==================+ +===========+==========================+=======+==================+
skipping to change at line 2549 skipping to change at line 2521
+-----------+--------------------------+-------+------------------+ +-----------+--------------------------+-------+------------------+
| depend | The attribute value MUST | M | IDENTICAL-PER-PT | | depend | The attribute value MUST | M | IDENTICAL-PER-PT |
| lay | be the same for a given | | | | lay | be the same for a given | | |
| | codec configuration. | | | | | codec configuration. | | |
+-----------+--------------------------+-------+------------------+ +-----------+--------------------------+-------+------------------+
| depend | The attribute value MUST | M | IDENTICAL-PER-PT | | depend | The attribute value MUST | M | IDENTICAL-PER-PT |
| mdc | be the same for a given | | | | mdc | be the same for a given | | |
| | codec configuration. | | | | | codec configuration. | | |
+-----------+--------------------------+-------+------------------+ +-----------+--------------------------+-------+------------------+
Table 71: RFC 5583 Attribute Analysis Table 69: RFC 5583 Attribute Analysis
8.6. RFC 7104: Duplication Grouping Semantics in the SDP 8.6. RFC 7104: Duplication Grouping Semantics in the SDP
[RFC7104] defines the semantics for grouping redundant streams in [RFC7104] defines the semantics for grouping redundant streams in
SDP. The semantics defined in this document are to be used with the SDP. The semantics defined in this document are to be used with the
SDP Grouping Framework. Grouping semantics at the synchronization SDP Grouping Framework. Grouping semantics at the synchronization
source (SSRC) level are also defined in this document for RTP streams source (SSRC) level are also defined in this document for RTP streams
using SSRC multiplexing. using SSRC multiplexing.
+===========+==============+=======+==============+ +===========+==============+=======+==============+
| Name | Notes | Level | Mux Category | | Name | Notes | Level | Mux Category |
+===========+==============+=======+==============+ +===========+==============+=======+==============+
| group:DUP | Not impacted | S | NORMAL | | group:DUP | Not impacted | S | NORMAL |
+-----------+--------------+-------+--------------+ +-----------+--------------+-------+--------------+
Table 72: RFC 7104 Attribute Analysis Table 70: RFC 7104 Attribute Analysis
9. ssrc-group Attribute Analysis 9. ssrc-group Attribute Analysis
This section analyzes "ssrc-group" semantics. This section analyzes "ssrc-group" semantics.
9.1. RFC 5576: Source-Specific SDP Attributes 9.1. RFC 5576: Source-Specific SDP Attributes
[RFC5576] defines a mechanism for describing RTP media sources -- [RFC5576] defines a mechanism for describing RTP media sources --
which are identified by their synchronization source (SSRC) which are identified by their synchronization source (SSRC)
identifiers -- in SDP, to associate attributes with these sources and identifiers -- in SDP, to associate attributes with these sources and
skipping to change at line 2590 skipping to change at line 2562
+===================+==============+=======+==============+ +===================+==============+=======+==============+
| Name | Notes | Level | Mux Category | | Name | Notes | Level | Mux Category |
+===================+==============+=======+==============+ +===================+==============+=======+==============+
| ssrc-group:FID | Not impacted | SR | NORMAL | | ssrc-group:FID | Not impacted | SR | NORMAL |
+-------------------+--------------+-------+--------------+ +-------------------+--------------+-------+--------------+
| ssrc-group:FEC | Not impacted | SR | NORMAL | | ssrc-group:FEC | Not impacted | SR | NORMAL |
+-------------------+--------------+-------+--------------+ +-------------------+--------------+-------+--------------+
| ssrc-group:FEC-FR | Not impacted | SR | NORMAL | | ssrc-group:FEC-FR | Not impacted | SR | NORMAL |
+-------------------+--------------+-------+--------------+ +-------------------+--------------+-------+--------------+
Table 73: RFC 5576 Attribute Analysis Table 71: RFC 5576 Attribute Analysis
9.2. RFC 7104: Duplication Grouping Semantics in the SDP 9.2. RFC 7104: Duplication Grouping Semantics in the SDP
[RFC7104] defines the semantics for grouping redundant streams in [RFC7104] defines the semantics for grouping redundant streams in
SDP. The semantics defined in this document are to be used with the SDP. The semantics defined in this document are to be used with the
SDP Grouping Framework. Grouping semantics at the synchronization SDP Grouping Framework. Grouping semantics at the synchronization
source (SSRC) level are also defined in this document for RTP streams source (SSRC) level are also defined in this document for RTP streams
using SSRC multiplexing. using SSRC multiplexing.
+================+==============+=======+==============+ +================+==============+=======+==============+
| Name | Notes | Level | Mux Category | | Name | Notes | Level | Mux Category |
+================+==============+=======+==============+ +================+==============+=======+==============+
| ssrc-group:DUP | Not impacted | SR | NORMAL | | ssrc-group:DUP | Not impacted | SR | NORMAL |
+----------------+--------------+-------+--------------+ +----------------+--------------+-------+--------------+
Table 74: RFC 7104 Attribute Analysis Table 72: RFC 7104 Attribute Analysis
10. QoS Mechanism Token Analysis 10. QoS Mechanism Token Analysis
This section analyzes QoS tokes specified with SDP. This section analyzes QoS tokes specified with SDP.
10.1. RFC 5432: QoS Mechanism Selection in SDP 10.1. RFC 5432: QoS Mechanism Selection in SDP
[RFC5432] defines procedures to negotiate QoS mechanisms using the [RFC5432] defines procedures to negotiate QoS mechanisms using the
SDP offer/answer model. SDP offer/answer model.
skipping to change at line 2632 skipping to change at line 2604
| | that corresponds to the "m=" | | | | | that corresponds to the "m=" | | |
| | line chosen for setting up the | | | | | line chosen for setting up the | | |
| | underlying transport flow. | | | | | underlying transport flow. | | |
+------+--------------------------------+-------+-----------+ +------+--------------------------------+-------+-----------+
| nsis | rsvp attribute MUST be the one | B | TRANSPORT | | nsis | rsvp attribute MUST be the one | B | TRANSPORT |
| | that corresponds to the "m=" | | | | | that corresponds to the "m=" | | |
| | line chosen for setting up the | | | | | line chosen for setting up the | | |
| | underlying transport. | | | | | underlying transport. | | |
+------+--------------------------------+-------+-----------+ +------+--------------------------------+-------+-----------+
Table 75: RFC 5432 Attribute Analysis Table 73: RFC 5432 Attribute Analysis
NOTE: A single Differentiated Services Code Point (DSCP) for each NOTE: A single Differentiated Services Code Point (DSCP) for each
flow being multiplexed doesn't impact multiplexing, since QoS flow being multiplexed doesn't impact multiplexing, since QoS
mechanisms are signaled/scoped per flow. For scenarios that involve mechanisms are signaled/scoped per flow. For scenarios that involve
having different DSCP code points for packets being transmitted over having different DSCP code points for packets being transmitted over
the same 5-tuple, issues as discussed in [RFC7657] need to be taken the same 5-tuple, issues as discussed in [RFC7657] need to be taken
into consideration. into consideration.
11. k= Attribute Analysis 11. k= Attribute Analysis
skipping to change at line 2656 skipping to change at line 2628
sessions for the purposes of session announcement, session sessions for the purposes of session announcement, session
invitation, and other forms of multimedia session initiation. invitation, and other forms of multimedia session initiation.
+======+===================================+=======+==============+ +======+===================================+=======+==============+
| Name | Notes | Level | Mux Category | | Name | Notes | Level | Mux Category |
+======+===================================+=======+==============+ +======+===================================+=======+==============+
| k= | It is not recommended to use this | S | CAUTION | | k= | It is not recommended to use this | S | CAUTION |
| | attribute under multiplexing. | | | | | attribute under multiplexing. | | |
+------+-----------------------------------+-------+--------------+ +------+-----------------------------------+-------+--------------+
Table 76: RFC 4566 Attribute Analysis Table 74: RFC 4566 Attribute Analysis
12. content Attribute Analysis 12. content Attribute Analysis
12.1. RFC 4796 12.1. RFC 4796
[RFC4796] defines a new SDP media-level attribute, "content". The [RFC4796] defines a new SDP media-level attribute, "content". The
"content" attribute defines the content of the media stream to a more "content" attribute defines the content of the media stream to a more
detailed level than the media description line. The sender of an SDP detailed level than the media description line. The sender of an SDP
session description can attach the "content" attribute to one or more session description can attach the "content" attribute to one or more
media streams. The receiving application can then treat each media media streams. The receiving application can then treat each media
skipping to change at line 2684 skipping to change at line 2656
+-----------------+--------------+-------+--------------+ +-----------------+--------------+-------+--------------+
| content:speaker | Not impacted | M | NORMAL | | content:speaker | Not impacted | M | NORMAL |
+-----------------+--------------+-------+--------------+ +-----------------+--------------+-------+--------------+
| content:main | Not impacted | M | NORMAL | | content:main | Not impacted | M | NORMAL |
+-----------------+--------------+-------+--------------+ +-----------------+--------------+-------+--------------+
| content:sl | Not impacted | M | NORMAL | | content:sl | Not impacted | M | NORMAL |
+-----------------+--------------+-------+--------------+ +-----------------+--------------+-------+--------------+
| content:alt | Not impacted | M | NORMAL | | content:alt | Not impacted | M | NORMAL |
+-----------------+--------------+-------+--------------+ +-----------------+--------------+-------+--------------+
Table 77: RFC 4796 Attribute Analysis Table 75: RFC 4796 Attribute Analysis
12.2. 3GPP TS 24.182
[IMS-CAT] specifies an IP multimedia subsystem for customized
alerting tones.
+============+=========================+=======+==============+
| Name | Notes | Level | Mux Category |
+============+=========================+=======+==============+
| g.3gpp.cat | Usage defined for the | M | NORMAL |
| | IP multimedia subsystem | | |
+------------+-------------------------+-------+--------------+
Table 76: 3GPP TS 24.182 Attribute Analysis
12.3. 3GPP TS 24.183
[IMS-CRS] specifies an IP multimedia subsystem for customized ringing
signal.
+============+=========================+=======+==============+
| Name | Notes | Level | Mux Category |
+============+=========================+=======+==============+
| g.3gpp.crs | Usage defined for the | M | NORMAL |
| | IP multimedia subsystem | | |
+------------+-------------------------+-------+--------------+
Table 77: 3GPP TS 24.183 Attribute Analysis
13. Payload Formats 13. Payload Formats
13.1. RFC 5109: RTP Payload Format for Generic FEC 13.1. RFC 5109: RTP Payload Format for Generic FEC
[RFC5109] describes a payload format for generic Forward Error [RFC5109] describes a payload format for generic Forward Error
Correction (FEC) for media data encapsulated in RTP. It is based on Correction (FEC) for media data encapsulated in RTP. It is based on
the exclusive-or (parity) operation. The payload format allows end the exclusive-or (parity) operation. The payload format allows end
systems to apply protection using various protection lengths and systems to apply protection using various protection lengths and
levels, in addition to using various protection group sizes to adapt levels, in addition to using various protection group sizes to adapt
skipping to change at line 3088 skipping to change at line 3088
+----------+--------------+ +----------+--------------+
| RS | SUM | | RS | SUM |
+----------+--------------+ +----------+--------------+
| RR | SUM | | RR | SUM |
+----------+--------------+ +----------+--------------+
| TIAS | SPECIAL | | TIAS | SPECIAL |
+----------+--------------+ +----------+--------------+
Table 80 Table 80
15.2.2. Table: att-field 15.2.2. Table: attribute-name
The following values have been added to the "att-field" subregistry The following values have been added to the "attribute-name"
of the "Session Description Protocol (SDP) Parameters" registry. The subregistry of the "Session Description Protocol (SDP) Parameters"
references have been updated to point to this RFC as well as the registry. The references have been updated to point to this RFC as
previous references. well as the previous references.
NOTE: The attributes from [FLUTE] ("flute-tsi", "flute-ch", "FEC- NOTE: The attributes from [FLUTE] ("flute-tsi", "flute-ch", "FEC-
declaration", "FEC-OTI-extension", "content-desc") were not analyzed declaration", "FEC-OTI-extension", "content-desc") were not analyzed
for their multiplexing behavior, due to the expired status of the for their multiplexing behavior, due to the expired status of the
draft. For the purposes of this specification, the multiplexing draft. For the purposes of this specification, the multiplexing
category of "TBD" is assigned. category of "TBD" is assigned.
+==========================+==================+ +==========================+==================+
| SDP Name | Mux Category | | SDP Name | Mux Category |
+==========================+==================+ +==========================+==================+
skipping to change at line 3510 skipping to change at line 3510
| repair-window | SPECIAL | | repair-window | SPECIAL |
+--------------------------+------------------+ +--------------------------+------------------+
| rams-updates | CAUTION | | rams-updates | CAUTION |
+--------------------------+------------------+ +--------------------------+------------------+
| imageattr | IDENTICAL-PER-PT | | imageattr | IDENTICAL-PER-PT |
+--------------------------+------------------+ +--------------------------+------------------+
| cfw-id | NORMAL | | cfw-id | NORMAL |
+--------------------------+------------------+ +--------------------------+------------------+
| portmapping-req | CAUTION | | portmapping-req | CAUTION |
+--------------------------+------------------+ +--------------------------+------------------+
| g.3gpp.crs | NORMAL |
+--------------------------+------------------+
| ecn-capable-rtp | IDENTICAL | | ecn-capable-rtp | IDENTICAL |
+--------------------------+------------------+ +--------------------------+------------------+
| visited-realm | TRANSPORT | | visited-realm | TRANSPORT |
+--------------------------+------------------+ +--------------------------+------------------+
| secondary-realm | TRANSPORT | | secondary-realm | TRANSPORT |
+--------------------------+------------------+ +--------------------------+------------------+
| omr-s-cksum | NORMAL | | omr-s-cksum | NORMAL |
+--------------------------+------------------+ +--------------------------+------------------+
| omr-m-cksum | NORMAL | | omr-m-cksum | NORMAL |
+--------------------------+------------------+ +--------------------------+------------------+
skipping to change at line 3603 skipping to change at line 3601
| speaker | NORMAL | | speaker | NORMAL |
+------------+--------------+ +------------+--------------+
| sl | NORMAL | | sl | NORMAL |
+------------+--------------+ +------------+--------------+
| main | NORMAL | | main | NORMAL |
+------------+--------------+ +------------+--------------+
| alt | NORMAL | | alt | NORMAL |
+------------+--------------+ +------------+--------------+
| g.3gpp.cat | NORMAL | | g.3gpp.cat | NORMAL |
+------------+--------------+ +------------+--------------+
| g.3gpp.crs | NORMAL |
+------------+--------------+
Table 82 Table 82
15.2.4. Table: Semantics for the "group" SDP Attribute 15.2.4. Table: Semantics for the "group" SDP Attribute
The following values have been added to the "Semantics for the The following values have been added to the "Semantics for the
'group' SDP Attribute" subregistry of the "Session Description 'group' SDP Attribute" subregistry of the "Session Description
Protocol (SDP) Parameters" registry. The references have been Protocol (SDP) Parameters" registry. The references have been
updated to point to this RFC as well as the previous references. updated to point to this RFC as well as the previous references.
skipping to change at line 4325 skipping to change at line 4325
suggesting the categories, contributing text, and reviewing the draft suggesting the categories, contributing text, and reviewing the draft
of this document. I would also like to thank Magnus Westerlund, of this document. I would also like to thank Magnus Westerlund,
Christer Holmberg, Jonathan Lennox, Bo Burman, Ari Keranen, and Dan Christer Holmberg, Jonathan Lennox, Bo Burman, Ari Keranen, and Dan
Wing for suggesting structural changes that improved the document's Wing for suggesting structural changes that improved the document's
readability. readability.
I would like also to thank the following experts for their inputs and I would like also to thank the following experts for their inputs and
reviews as listed: reviews as listed:
Flemming Andreasen (5.24, 5.32, 5.33, 14), Flemming Andreasen (5.24, 5.32, 5.33, 14),
Rohan Mahy (5.56), Rohan Mahy (5.54),
Eric Burger (5.26), Eric Burger (5.26),
Christian Huitema (5.14), Christian Huitema (5.14),
Christer Holmberg (5.21, 5.26, 5.50, 5.51), Christer Holmberg (5.21, 5.26, 12.2, 12.3),
Richard Ejzak (5.44, 5.52, 5.53), Richard Ejzak (5.44, 5.50, 5.51),
Colin Perkins (5.7, 5.8, 5.9, 5.57), Colin Perkins (5.7, 5.8, 5.9, 5.55),
Magnus Westerlund (5.2, 5.3, 5.9, 5.27, 5.47, 6.1 - 6.3, 8.3, 7), Magnus Westerlund (5.2, 5.3, 5.9, 5.27, 5.47, 6.1 - 6.3, 8.3, 7),
Roni Even (5.12, 5.27, 8.4), Roni Even (5.12, 5.27, 8.4),
Subha Dhesikan (5.6, 10), Subha Dhesikan (5.6, 10),
Dan Wing (5.7, 5.12, 5.35, 5.39, 5.45), Dan Wing (5.7, 5.12, 5.35, 5.39, 5.45),
Cullen Jennings (5.40), Cullen Jennings (5.40),
Ali C Begen (5.1, 5.20, 5.22, 5.25, 5.38, 7.3, 8.2, 8.4, 8.6, 9.2, Ali C Begen (5.1, 5.20, 5.22, 5.25, 5.38, 7.3, 8.2, 8.4, 8.6, 9.2,
13.1), 13.1),
Bo Burman (7.2, 7.6), Bo Burman (7.2, 7.6),
Charles Eckel (5.15, 5.27, 5.28, 9.1, 8.5), Charles Eckel (5.15, 5.27, 5.28, 9.1, 8.5),
Paul Kyzivat (5.24), Paul Kyzivat (5.24),
Ian Johansson (5.15), Ian Johansson (5.15),
Saravanan Shanmugham (5.11), Saravanan Shanmugham (5.11),
Paul E Jones (5.30), Paul E Jones (5.30),
Rajesh Kumar (5.48), Rajesh Kumar (5.48),
Jonathan Lennox (5.36, 5, 15, 9.1, 11.1), Jonathan Lennox (5.36, 5, 15, 9.1, 11.1),
Mo Zanaty (5.4, 5.5, 5.23, 8.1, 8.3, 8.5, 12.1), Mo Zanaty (5.4, 5.5, 5.23, 8.1, 8.3, 8.5, 12.1),
Christian Huitema (5.14), Christian Huitema (5.14),
Qin Wu (5.47, PM-Dir review), Qin Wu (5.47, PM-Dir review),
Hans Stokking (5.43, 5.16), Hans Stokking (5.43, 5.16),
Christian Groves (5.48, 5.54), and Christian Groves (5.48, 5.52), and
Thomas Stach. Thomas Stach.
I would like to thank Chris Lonvick for the SECDIR review, Dan I would like to thank Chris Lonvick for the SECDIR review, Dan
Romascanu for the Gen-ART review, and Sabrina Tanamal for the IANA Romascanu for the Gen-ART review, and Sabrina Tanamal for the IANA
review. review.
Thanks to Ben Campbell for Area Director review suggestions. Thanks Thanks to Ben Campbell for Area Director review suggestions. Thanks
to Spencer Dawkins, Stephen Farrel, Alissa Cooper, Mirja K├╝hlewind, to Spencer Dawkins, Stephen Farrel, Alissa Cooper, Mirja K├╝hlewind,
and the entire IESG for their reviews. and the entire IESG for their reviews.
 End of changes. 43 change blocks. 
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