One document matched: draft-ietf-avtcore-feedback-supression-rtp-07.xml
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<!DOCTYPE rfc SYSTEM "rfc2629.dtd">
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<rfc category="std" docName="draft-ietf-avtcore-feedback-supression-rtp-07"
ipr="trust200902">
<front>
<title abbrev="Third Party Loss Report">RTCP Extension for Third-party
Loss Report</title>
<author fullname="Qin Wu" initials="Q." surname="Wu">
<organization>Huawei</organization>
<address>
<postal>
<street>101 Software Avenue, Yuhua District</street>
<city>Nanjing</city>
<region>Jiangsu</region>
<code>210012</code>
<country>China</country>
</postal>
<email>sunseawq@huawei.com</email>
</address>
</author>
<author fullname="Frank Xia" initials="F." surname="Xia">
<organization>Huawei</organization>
<address>
<postal>
<street>1700 Alma Dr. Suite 500</street>
<city>Plano</city>
<region>TX 75075</region>
<country>USA</country>
</postal>
<phone>+1 972-509-5599</phone>
<email>xiayangsong@huawei.com</email>
</address>
</author>
<author fullname="Roni Even" initials="R." surname="Even">
<organization>Huawei</organization>
<address>
<postal>
<street>14 David Hamelech</street>
<region>Tel Aviv 64953</region>
<country>Israel</country>
</postal>
<email>even.roni@huawei.com</email>
</address>
</author>
<date month="September" year="2011" />
<workgroup>Network Working Group</workgroup>
<abstract>
<t>In a large RTP session using the RTCP feedback mechanism defined in
RFC 4585, 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. This
memo discusses these cases and defines a new RTCP third-party loss
report that can be used to inform receivers that the network is aware of
some loss event, allowing them to suppress feedback. Associated SDP
signalling is also defined.</t>
</abstract>
</front>
<middle>
<section title="Introduction">
<t>RTCP feedback messages <xref target="RFC4585"></xref> allow the
receivers in an RTP session to report events and ask for action from the
media source (or a delegated feedback target when using unicast RTCP
feedback with SSM <xref target="RFC5760"></xref>). There are cases where
multiple receivers may initiate the same, or an equivalent message
towards the same media source. When the receiver count is large, this
behavior may cause transient overload of the media source, the network
or both. This is known as a "feedback storm" or a "NACK storm". One
common cause of such a feedback storm is receivers utilizing RTP
retransmission <xref target="RFC4588"></xref> as a packet loss recovery
technique based, sending feedback using RTCP NACK messages <xref
target="RFC4585"></xref> without proper dithering of the retransmission
requests (e.g., implementing the RFC 4585 dithering rules or sending
NACKs to a middlebox that doesn't redistribute them to other
receivers).</t>
<t>Another use case involves video Fast Update requests. A storm of
these feedback messages can occur in conversational multimedia scenarios
like multipoint video switching conference <xref
target="RFC4587"></xref>. In this scenario, the receiver may lose
synchronization with the video stream when speaker is changed in the
middle of session. Poorly designed receivers that blindly issue fast
update requests (i.e., Full Intra Request (FIR) described in <xref
target="RFC5104"></xref>), can cause an implosion of FIR requests from
receivers to the same media source.</t>
<t>RTCP feedback storms may cause short term overload, and in extreme
cases to pose a possible risk of increasing network congestion on the
control channel (e.g. RTCP feedback), the data channel, or both. It is
therefore desirable to provide a way of suppressing unneeded
feedback.</t>
<t>One approach to this, suggested in <xref target="DVB-IPTV"></xref>,
involves sending a NACK message to the other clients (or receiver) in
the same group as the sender of NACK. However NACK is defined as a
receiver report sent from a receiver observing a packet loss, therefore
it only inform others that sender of NACK detected loss while the case
the sender of the feedback has received reports that the indicated
packets were lost is not covered. This document specifies a new
third-party loss report for this function. It supplements the existing
the use of RTCP NACK packet and further is more precise in the uses
where the network is active to suppress feedback. It tells receivers
explicitly that feedback for a particular packet or frame loss is not
needed for a period of time and can provide an early indication before
the receiver reacts to the loss and invokes its packet loss repair
machinery. Section 6 provides some examples of when to send the Third
Party Loss Report message. <xref target="Use"></xref> provides some
examples of when to send the Third Party Loss Report message.</t>
</section>
<section title="Terminology">
<t>The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"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="Protocol Overview">
<t>This document extends the RTCP feedback messages defined in the
Audio-Visual Profile with feedback (RTP/AVPF) <xref
target="RFC4585"></xref> defining a Third Party Loss Report message. The
Third Party Loss Report message can be used by the intermediaries to
inform the receiver that the sender of the Third Party Loss Report has
received reports that the indicated packets were lost, and asks the
receiver not to send feedback to it regarding these packets.</t>
<t>RTCP Third Party Loss Report follows the similar format of message
type as RTCP NACK or Full Intra Request Command. However, the Third
Party Loss Report is defined as an indication that the sender of the
feedback has received reports that the indicated packets were lost,
while NACK <xref target="RFC4585"></xref> just indicates that the sender
of the NACK observed that these packets were lost. The Third Party Loss
Report message is generated by a RTP system that has not seen the actual
packet loss and sent following the same timing rule as sending NACK
defined in <xref target="RFC4585"></xref>, e.g., The TPLR message may be
sent in a regular full compound RTCP packet or in an early RTCP packet,
as per AVPF. RTP Systems in the network that receive a Third Party Loss
Report SHOULD NOT initiate their own additional Third Party Loss Report
messages for the same packet sequence numbers. They should simply
forward the Third Party Loss Report message received from upstream
direction, additionally, they may generate their own Third Party Loss
Report that reports a set of the losses they see, which are different
from ones reported in the Third Party Loss report they received. The
Third Party Loss Report does not have the retransmission request <xref
target="RFC4588"></xref> semantics.</t>
<t>When a receiver gets a Third Party Loss Report message, it should
start a timer for this message and refrain from sending a feedback
request (e.g., NACK or FIR) for the missing packets reported in the
message during the lifetime of the timer. The timer value shall be based
on the observed round-trip time. A receiver should compute an estimate
of the round-trip time (RTT) to the sender of TPLR from RTCP report
round-trip time if available, or its reception time of the reflected
RTCP FB message (e.g.,NACK), or any other means.</t>
<t>To increase the robustness to the loss of a TPLR or of a transmission
packet, a receiver is allowed to receive additional TPLR for the same
packet. In the case the first TPLR is lost and the additional TPLR
arrives at the receiver, the receiver should immediately refresh the
timer. When the timer for this message expires and there is no
retransmitted packet or a new Third Party Loss Report message, the
receiver should take its normal behavior as if there is no current
retransmission suppression.</t>
<t>A receiver may still have sent a Feedback message according to the
RTP/AVPF scheduling algorithm of <xref target="RFC4585"></xref> before
receiving a Third Party Loss Report message, but further feedback
messages for those sequence numbers will be suppressed by this technique
for a certain period of time. Nodes that do not understand the Third
Party Loss Report message will ignore it, and might therefore still send
feedback according to the AVPF scheduling algorithm of <xref
target="RFC4585"></xref>. The media source or intermediate nodes cannot
assume that the use of a Third Party Loss Report message actually
reduces the amount of feedback it receives.</t>
<t>Since Third Party Loss Report interacts strongly with repair timing,
it has to work together with feedback to not adversely impact the repair
of lost source packets. In order not to incur a lot of NACK requests due
to additional TPLR described above, it is recommended that the RTP
system sending TPLR should be implemented more closer to the source.
Also when the loss was detected and repair initiated much closer to the
source, the delay for the receiver to recover from packet loss can be
reduced through the combination of intermediary feedback to the source
and Third Party Loss Report downstream.</t>
</section>
<section anchor="sec4" title="Format of RTCP Feedback Messages">
<t>This document registers two new RTCP Feedback messages for Third
Party Loss Report. Applications that are employing one or more loss-
repair methods MAY use the Third Party Loss Report together with their
existing loss-repair methods either for every packet they expect to
receive, or for an application-specific subset of the RTP packets in a
session. In other words, receivers MAY ignore Third Party Loss Report
messages, but SHOULD react to them unless they have good reason to still
send feedback messages despite having been requested to suppress
them.</t>
<section title="Transport Layer Feedback: Third-party Loss Report">
<t>This Third Party Loss Report message is an extension to the RTCP
Transport Layer Feedback Report and identified by RTCP packet type
value PT=RTPFB and FMT=TBD.</t>
<t>Within the common packet header for feedback messages (as defined
in section 6.1 of <xref target="RFC4585"></xref>), the "SSRC of packet
sender" field indicates the source of the request, and the "SSRC of
media source" denotes the media sender.</t>
<t>The FCI field MUST contain one or more entries of transport layer
third party loss Early Indication (TLLEI). Each entry applies to the
same media source identified by the SSRC contained in the SSRC of
media source field of Feedback header.</t>
<t>The Feedback Control Information (FCI) for TLLEI uses the similar
format of message Types defined in the section 6.2.1 of <xref
target="RFC4585"></xref>. The format is shown in <xref
target="fig2"></xref>.</t>
<figure align="center" anchor="fig2"
title="Message Format for the Third Party Loss Report">
<artwork>
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PID | BLP |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
</artwork>
</figure>
<t><list style="hanging">
<t hangText="Packet ID (PID): 16 bits"><vspace blankLines="1" />
The PID field is used to specify a lost packet. The PID field
refers to the RTP sequence number of the lost packet.<vspace
blankLines="1" /></t>
<t
hangText="bitmask of proceeding lost packets (BLP): 16 bits"><vspace
blankLines="1" /> The BLP allows for reporting losses of any of
the 16 RTP packets immediately following the RTP packet indicated
by the PID. The BLP's definition is identical to that given in
<xref target="RFC4585"></xref>.<vspace blankLines="1" /></t>
</list></t>
</section>
<section title="Payload Specific Feedback: Third-party Loss Report">
<t>This message is an extension to the RTCP Payload Specific Feedback
report and identified by RTCP packet type value PT=PSFB and FMT=TBD,
which is used to suppress FIR <xref target="RFC5104"></xref>or PLI
<xref target="RFC4585"></xref>.</t>
<t>Within the common packet header for feedback messages (as defined
in section 6.1 of <xref target="RFC4585"></xref>), the "SSRC of packet
sender" field indicates the source of the request, and the "SSRC of
media source" is not used and SHALL be set to 0. The SSRCs of the
media senders to which this message applies are in the corresponding
FCI entries.</t>
<t>The FCI field MUST contain a Payload Specific Third Party Loss
Early Indication (PSLEI) entry. Each entry applies to a different
media Source that is requested to send a decoder refresh point or that
is indicated that it lost synchronization with the video stream,
identified by its SSRC.</t>
<t>The Feedback Control Information (FCI) for PSLEI uses the similar
format of message Types defined in the section 4.3.1.1 of <xref
target="RFC5104"></xref>. The format is shown in <xref
target="fig3"></xref>.</t>
<figure align="center" anchor="fig3"
title="Message Format for the Third Party Loss Report">
<artwork>
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Seq nr. | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
</artwork>
</figure>
<t><list style="hanging">
<t hangText="SSRC (32 bits): "><vspace blankLines="1" />The SSRC
value of the media source that is requested to send a decoder
refresh point or that is indicated that it lost synchronization
with the video stream. <vspace blankLines="1" /></t>
<t hangText="Seq nr:8bits">Command sequence number. It is used by
the Command receiver to check if the Command is repeated. The
sequence number space is unique for each pairing of the SSRC of
command sender and the SSRC of the command receiver. The sequence
number SHALL increase by 1 modulo 256 for each new Command. A
repetition SHALL NOT increase the sequence number. The initial
value is arbitrary. <vspace blankLines="1" /></t>
<t hangText="Reserved: 24 bits"><vspace blankLines="1" />All bits
SHALL be set to 0 by the media source and SHALL be ignored on
reception.<vspace blankLines="1" /></t>
</list></t>
</section>
</section>
<section title="SDP Signaling">
<t>A new feedback value "tplr" needs to be defined for the Third Party
Loss Report message to be used with Session Description Protocol (SDP)
<xref target="RFC4566"></xref> using the Augmented Backus-Naur Form
(ABNF) <xref target="RFC4585"></xref>.</t>
<t>The "tplr" feedback value SHOULD be used with parameters that
indicate the third party loss supported. In this document, we define two
such parameter, namely: <vspace blankLines="1" /><list style="symbols">
<t>"tllei" denotes support of transport layer third party loss early
indication.<vspace blankLines="1" /></t>
<t>"pslei" denotes support of payload specific third party loss
early indication.</t>
</list><vspace blankLines="1" />In the ABNF for rtcp-fb-val defined in
<xref target="RFC4585"></xref>, there is a placeholder called rtcp-fb-id
to define new feedback types. "tplr" is defined as a new feedback type
in this document, and the ABNF for the parameters for tplr is defined
here (please refer to section 4.2 of <xref target="RFC4585"></xref> for
complete ABNF syntax).</t>
<figure align="center">
<artwork>
rtcp-fb-val =/ "tplr" rtcp-fb-tplr-param
rtcp-fb-tplr-param = SP "tllei";transport layer third party loss early indication
/ SP "pslei";payload specific third party loss early indication
/ SP token [SP byte-string]
; for future commands/indications
byte-string = <as defined in section 4.2 of [RFC4585] >
</artwork>
</figure>
<t>Refer to Section 4.2 of <xref target="RFC4585"></xref> for a detailed
description and the full syntax of the "rtcp-fb" attribute.</t>
</section>
<section anchor="Use" title="Example Use Cases">
<t>The operation of feedback suppression is similar for all types of RTP
sessions and topologies <xref target="RFC5117"></xref>, however the
exact messages used and the scenarios in which suppression is employed
differ for various use cases. The following sections outline some of the
intended use cases for using the Third Party Loss Report for feedback
suppression and give an overview of the particular mechanisms.</t>
<section title="Source Specific Multicast (SSM) use case">
<t>In SSM RTP sessions as described in <xref target="RFC5760"></xref>,
one or more Media Sources send RTP packets to a Distribution Source.
The Distribution Source relays the RTP packets to the receivers using
a source- specific multicast group.</t>
<t>As outlined in the <xref target="RFC5760"></xref>, there are two
Unicast Feedback models that may be used for reporting, the Simple
Feedback model and the Distribution Source Feedback Summary Model. In
the simple Feedback Model, there's no need for distribution source to
create the Third Party Loss Report, instead, NACKs are reflected by
the distribution source to the other Receivers. However in the
Distribution Source Feedback Summary model, the distribution source
will not redistribute the NACK for some reason(e.g., to prevent
revealing the identity or existence of a system sending NACK)and may
send a Third Party Loss Report to the systems that were unable to
receive the NACK, and won't receive the NACK via other means. since
the summary feedback does not mandate the forwarding of NACK
downstream. The Third Party Loss Report can be generated at the
distribution source when downstream loss is told (e.g., downstream
loss report is received), which indicates to the receivers that they
should not transmit feedback messages for the same loss event for a
certain time. Therefore the distribution source in the feedback
summary model can be reasonably certain that it will help the
situation by sending this Third Party Loss Report message to all the
relevant receivers impacted by the packet loss.</t>
</section>
<section title="Unicast based Rapid Acquisition of Multicast Stream (RAMS) use case">
<t>The typical RAMS architecture <xref target="RFC6285"></xref> may
have several Burst/ Retransmission Sources(BRS) behind the multicast
source (MS) placed at the same level. These BRSes will receive the
primary multicast RTP stream from the media source and cache most
recent packets after joining multicast session. If packet loss happens
at the upstream of all the BRSs or the downstream of one or more
BRSes. one of the BRSes or all the BRSes may send a NACK or TPLR
message to the DS, where the SSRC in this NACK or TPLR message is the
one of the BRS. The DS forwards/reflects this message down on the
primary SSM. The details on how DS deal with this message is specified
in <xref target="RETRANSMISSION-FOR-SSM"></xref>.</t>
</section>
<section title="RTP transport translator use case">
<t>A Transport Translator (Topo-Trn-Translator), as defined in <xref
target="RFC5117"></xref> is typically forwarding the RTP and RTCP
traffic between RTP clients, for example converting between multicast
and unicast for domains that do not support multicast. The translator
acting as quality monitoring <xref target="Monarch"></xref> may suffer
a loss of important video packets. In this case, the translator may
trigger repair by the media sender and at the same time,use it's own
SSRC as packet sender SSRC to create a new Third Party Loss Report
message and send it to the receivers that is not aware of packet
loss.</t>
</section>
<section title="Multipoint Control Unit (MCU) use case">
<t>When the speaker is changed in a voice-activated multipoint video
switching conference <xref target="RFC4587"></xref>, an RTP mixer can
be used to select the available input streams and forward them to each
participants. If the MCU is doing a blind switch without waiting for a
synchronization point on the new stream it can send a FIR to the new
video source. In this case the MCU should send a FIR suppression
message to the new receivers. e.g.,when the RTP Mixer starts to
receive FIR from some participants it can suppress the remaining
session participants from sending FIR by sending out a Third party
Loss report message.</t>
</section>
<section title="Mixer use Case">
<t>A Mixer, in accordance with <xref target="RFC5117"></xref>,
aggregates multiple RTP streams from other session participants and
generates a new RTP stream sent to the session participants. In some
cases, the video frames may get badly screwed up between media source
and the mixer. In such case, the mixer need to check if the packet
loss will result in PLI or FIR transmissions from most of the group by
analyzing the received video. If so the mixer initiates FIR or PLI
towards the media source on behalf of all the session participants and
send out a Third party Loss report message to these session
participants that may or are expected to send a PLI or FIR Another
possible way for mixer to deal with, is when the mixer starts to
receive FIR or PLI from some participants and like to suppress the
remaining session participants from sending FIR or PLI by sending out
a Third party Loss report message.</t>
</section>
</section>
<section title="Security Considerations">
<t>The defined messages have certain properties that have security
implications. These must be addressed and taken into account by users of
this protocol.</t>
<t>Spoofed or maliciously created feedback messages of the type defined
in this specification can have the following implications:</t>
<t>Sending the spurious Third Party Loss Report (e.g., the Third Party
Loss Report with the wrong sequence number of lost packet) that makes
missing RTP packets can not be compensated.</t>
<t>To prevent these attacks, there is a need to apply authentication and
integrity protection of the feedback messages. This can be accomplished
against threats external to the current RTP session using the RTP
profile that combines Secure RTP <xref target="RFC3711"></xref> and AVPF
into SAVPF <xref target="RFC5124"></xref>.</t>
<t>Note that middleboxes that are not visible at the RTP layer that wish
to send the Third Party Loss Reports on behalf of the media source can
only do so if they spoof the SSRC of the media source. This is difficult
in case SRTP is in use. If the middlebox is visible at the RTP layer,
this is not an issue, provided the middlebox is part of the security
context for the session.</t>
<t>Also note that endpoints that receive a Third Party Loss Report would
be well-advised to ignore it, unless the security is in place to
authenticate the sender of the Third Party Loss Report. Accepting Third
Party Loss Report from un-authenticated sender can lead to a denial of
service attack, where the endpoint accepts poor quality media that could
be repaired.</t>
</section>
<section title="IANA Consideration">
<t>The new value "TPLR" has been registered with IANA in the "rtcp-fb"
Attribute Values registry located at the time of publication at:
http://www.iana.org/assignments/sdp-parameters <figure>
<artwork>
Value name: tplr
Long Name: Third Party Loss Reports
Reference: This document
</artwork>
</figure></t>
<t>A new registry " Third Party Loss Report Messages" has been created
to hold "tplr" parameters located at time of publication at:
http://www.iana.org/assignments/sdp-parameters</t>
<t>New registration in this registry follows the "Specification
required" policy as defined by [RFC2434]. In addition, they are required
to indicate any additional RTCP feedback types, such as "nack" and
"ack".</t>
<t>The following values have been registered as FMT values in the "FMT
Values for RTPFB Payload Types" registry located at the time of
publication at: http://www.iana.org/assignments/rtp-parameters <figure>
<artwork>
RTPFB range
Name Long Name Value Reference
-------------- --------------------------------- ----- ---------
TLLEI Transport Layer Third Party X [RFCXXXX]
Loss Early Indication
</artwork>
</figure></t>
<t>The following values have been registered as FMT values in the "FMT
Values for PSFB Payload Types" registry located at the time of
publication at: http://www.iana.org/assignments/rtp-parameters <figure>
<artwork>
PSFB range
Name Long Name Value Reference
-------------- --------------------------------- ----- ---------
PSLEI Payload Specific Third Party X [RFCXXXX]
Loss Early Indication
</artwork>
</figure></t>
</section>
<section title="Acknowledgement">
<t>The authors would like to thank David R Oran, Magnus Westerlund,
Colin Perkins, Ali C. Begen, Tom VAN CAENEGEM, Ingemar Johansson S, Bill
Ver Steeg, Jonathan Lennox, WeeSan Lee for their valuable comments and
suggestions on this document.</t>
</section>
</middle>
<back>
<references title="Normative References">
<?rfc include="reference.RFC.5760"?>
<?rfc include="reference.RFC.2119"?>
<?rfc include="reference.RFC.4585"?>
<?rfc include="reference.RFC.3550"?>
<?rfc include="reference.RFC.4588"?>
<?rfc include="reference.RFC.4566"?>
<?rfc include="reference.RFC.5234"?>
<?rfc include="reference.RFC.5104"?>
<?rfc include="reference.RFC.3711"?>
<?rfc include="reference.RFC.5124"?>
</references>
<references title="Informative References">
<reference anchor="RFC5740">
<front>
<title>NACK-Oriented Reliable Multicast (NORM) Transport
Protocol</title>
<author fullname="Brian Adamson" initials="B." surname="Adamson">
<organization>Naval Research Laboratory</organization>
</author>
<author fullname="Carsten Bormann" initials="C." surname="Bormann">
<organization>Universitaet Bremen TZI</organization>
</author>
<author fullname="Mark Handley " initials="M." surname="Handley">
<organization>University College London</organization>
</author>
<author fullname="Joe Macker" initials="J." surname="Macker">
<organization>Naval Research Laboratory</organization>
</author>
<date month="November" year="2009" />
</front>
</reference>
<reference anchor="DVB-IPTV">
<front>
<title>Digital Video Broadcasting(DVB); Transport of MPEG-2 TS Based
DVB Services over IP Based Networks</title>
<author>
<organization>ETSI Standard</organization>
</author>
<date month="August" year="2009" />
</front>
<seriesInfo name="ETSI TS 102 034, V1.4.1" value="" />
</reference>
<reference anchor="RFC6285">
<front>
<title>Unicast- Based Rapid Acquisition of Multicast RTP
Sessions</title>
<author fullname="Bill Steeg" initials="B." surname="Steeg">
<organization>Cisco</organization>
</author>
<author fullname="Ali Begen" initials="A." surname="Begen">
<organization>Cisco</organization>
</author>
<author fullname="Tom Caenegem" initials="T." surname="Caenegem">
<organization>Alcatel-Lucent</organization>
</author>
<author fullname="Zeev Vax" initials="Z." surname="Vax">
<organization>Microsoft</organization>
</author>
<date month="June" year="2011" />
</front>
</reference>
<reference anchor="Monarch">
<front>
<title>Monitoring Architectures for RTP</title>
<author fullname="Qin Wu" initials="Q." surname="Wu">
<organization>Huawei</organization>
</author>
<author fullname="Geoff Hunt" initials="G." surname="Hunt">
<organization>naffiliated</organization>
</author>
<author fullname="Philip Arden" initials="P." surname="Arden">
<organization>BT</organization>
</author>
<date month="June" year="2011" />
</front>
</reference>
<reference anchor="RETRANSMISSION-FOR-SSM">
<front>
<title>Retransmission for Source-Specific Multicast (SSM)
Sessions</title>
<author fullname="Tom Caenegem" initials="T." surname="Caenegem">
<organization>Alcatel-Lucent</organization>
</author>
<author fullname="Bill Steeg" initials="B." surname="Steeg">
<organization>Cisco</organization>
</author>
<author fullname="Ali Begen" initials="A." surname="Begen">
<organization>Cisco</organization>
</author>
<date month="May" year="2011" />
</front>
</reference>
<?rfc include="reference.RFC.5117"?>
<?rfc include="reference.RFC.4587"?>
</references>
<section title="Change Log">
<t>Note to the RFC-Editor: please remove this section prior to
publication as an RFC.</t>
<section title="draft-ietf-avtcore-feedback-suppression-rtp-01">
<t>The following are the major changes compared to previous version:
<vspace blankLines="1" /><list style="symbols">
<t>Remove the merge report from SSM use case and additional text
to address report merging issue.<vspace blankLines="1" /></t>
<t>Revise section 3 and section 6 to address FEC packet dealing
issue and Leave how to repair packet loss beyond the scope.<vspace
blankLines="1" /></t>
<t>Modify the SSM use case and RAMS use case to focus on
uses.<vspace blankLines="1" /></t>
<t>Other Editorial changes.</t>
</list></t>
</section>
<section title="draft-ietf-avtcore-feedback-suppression-rtp-02">
<t>The following are the major changes compared to previous version:
<vspace blankLines="1" /><list style="symbols">
<t>In Section 4.1, fix typo: Section 4.3.1.1 of section
[RFC5104]-> section 6.2.1 of [RFC4585].<vspace
blankLines="1" /></t>
<t>In Section 3: Clarify how to deal with downstream loss using
Third party loss report and upstream loss using NACK.<vspace
blankLines="1" /></t>
<t>Update title and abstract to focus on third party loss
report.<vspace blankLines="1" /></t>
<t>In Section 6.1: Update this section to explain how third party
loss report is used to deal with downstream loss.<vspace
blankLines="1" /></t>
<t>In section 6.1.2: Update this section to explain how third
party loss report is used to deal with downstream loss.<vspace
blankLines="1" /></t>
<t>In section 6.2: Rephrase the text to discuss how BRS deal with
the third party loss report.</t>
</list></t>
</section>
<section title="draft-ietf-avtcore-feedback-suppression-rtp-03">
<t>The following are the major changes compared to previous
version:<vspace blankLines="1" /><list style="symbols">
<t>In Appendix A, fix typo: Appendix A. Appendix A. -> Appendix
A.<vspace blankLines="1" /></t>
<t>Update abstract to clarify when third-party loss reports should
be sent instead of NACKs.<vspace blankLines="1" /></t>
<t>Update section 3 Paragraph 2 to differentiate when a
third-party loss report should be used compared to a NACK.<vspace
blankLines="1" /></t>
<t>Update section 3 Paragraph 3 to explain when media source to
send a third-party loss.<vspace blankLines="1" /></t>
<t>Move specific rules for section 6.1.1 and section 6.1.2 to
section 6.1 as generic rules and delete section 6.1.1.</t>
</list></t>
</section>
<section title="draft-ietf-avtcore-feedback-suppression-rtp-04">
<t>The following are the major changes compared to previous version:
<list style="symbols">
<t>Reference Update.<vspace blankLines="1" /></t>
<t>Clarify the use of the third party loss report in section 3 and
section 6.1.1.</t>
</list></t>
</section>
<section title="draft-ietf-avtcore-feedback-suppression-rtp-05">
<t>The following are the major changes compared to previous version:
<list style="symbols">
<t>Remove 3rd and 4th paragraphs of section 6.1 and replaced them
with 2nd and 3rd paragraphs of section 3.<vspace
blankLines="1" /></t>
<t>Remove section 6.1.1.1.<vspace blankLines="1" /></t>
<t>Revise the last paragraph of section 1 to clarify the rationale
of using new message.<vspace blankLines="1" /></t>
<t>Update RTP transport translator case in section 6.3 to correct
the use of the third party loss report.<vspace
blankLines="1" /></t>
<t>Update MCU case in section 6.4 to correct the use of the third
party loss report.<vspace blankLines="1" /></t>
<t>Revise SSM use case to address multiple DS issue.<vspace
blankLines="1" /></t>
<t>References Update.<vspace blankLines="1" /></t>
<t>Move one rationale on preventing sending unicast NACK in
introduction section to SSM case section.<vspace
blankLines="1" /></t>
<t>Other Editorial changes to section 6.1, 6.1.1, 6.2.</t>
</list></t>
</section>
<section title="draft-ietf-avtcore-feedback-suppression-rtp-06">
<t>The following are the major changes compared to previous version:
<vspace blankLines="1" /><list style="symbols">
<t>A few Editorial changes to the whole document.</t>
</list></t>
</section>
<section title="draft-ietf-avtcore-feedback-suppression-rtp-07">
<t>The following are the major changes compared to previous version:
<vspace blankLines="1" /><list style="symbols">
<t>Restructuring the protocol overview section to clarify the
round trip time calculation and receiver behavior to the
additional TPLR.<vspace blankLines="1" /></t>
<t>Restructuring the SSM use case section to focus on the use of
TPLR.<vspace blankLines="1" /></t>
<t>Editorial changes to the abstract, introduction, message
format, use cases and IANA sections.<vspace blankLines="1" /></t>
<t>References update</t>
</list></t>
</section>
</section>
</back>
</rfc>
| PAFTECH AB 2003-2026 | 2026-04-24 05:55:13 |