One document matched: draft-ietf-avtcore-feedback-supression-rtp-06.xml
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<rfc category="std" docName="draft-ietf-avtcore-feedback-supression-rtp-06"
ipr="pre5378Trust200902">
<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="August" 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 a feedback target 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.</t>
<t>Another use case involves video Fast Update requests. A storm of
these feedback messages can occur in conversational multimedia scenarios
like Topo-Video-switch-MCU <xref target="RFC5117"></xref>. In this
scenario, packet loss may happen on an upstream link of an intermediate
network element such as a Multipoint Control Unit(MCU). 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 further is more precise in
the intended uses and less likely to be confusing to receivers. 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. <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 media source or
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>When a receiver gets a Third Party Loss Report message, it should
refrain from sending a feedback request (e.g., NACK or FIR) for the
missing packets reported in the message for a certain period of time. 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>RTCP Third Party Loss Report follows the similar format of message
type as RTCP NACK. 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 system
that has not seen the actual packet loss. Systems 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 may
either simply forward the Third Party Loss Report message, or 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>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. One example is the middle box gets the
retransmitted packet by sending a NACK upstream and sent it downstream.
This retransmitted packet was lost on the downstream link. In order to
deal with this, the downstream receiver can start a timeout in which it
expected to get a retransmission packet. When this timeout expires and
there is no retransmitted packet or a new Third Party Loss Report
message, it can take its normal behavior as if there is no current
retransmission suppression. In the case 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>The FCI field MUST contain one or more entries of transport layer
third party loss Early Indication (TLLEI). Each entry applies to a
different media source, identified by its SSRC.</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.</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, 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.<vspace blankLines="1" /></t>
<t hangText="Seq nr:8bits">Command sequence number. The sequence
number space is unique for each pairing of the SSRC of command
source and the SSRC of the command target. The sequence number
SHALL be increased by 1 modulo 256 for each new request.<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. Note that each receiver sending
multicast NACK to its group may still need to send unicast NACK
addressed to the media source or distribution source for lost packets,
this may lead to a NACK storm if feedback suppression is not performed
and if the RTCP bandwidth limit is misconfigured.</t>
<t>As outlined in the [RFC5760], 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, NACKs are reflected by the distribution source to the other
receivers, and there's no need for distribution source to create the
Third Party Loss Report. The Third Party Loss Report may be generated
at the distribution source when downstream loss report is received in
the Distribution Source Feedback Summary model, since this summary
feedback does not mandate the forwarding of NACK downstream.</t>
<t>In order to observe packet loss before the receivers perceive it,
one or more intermediate nodes may be placed between the media source
and the receivers. These intermediaries monitor for upstream packet
loss . These intermediates may be Distribution source, MCUs, RTP
translator, or RTP mixers, depending on the precise implementation. If
an intermediary notices the loss itself, then it may send a NACK both
downstream towards the receivers and upstream towards the media
source, to indicate that it has noticed the loss, and to suppress
feedback from other downstream receivers. In the SSM case, If the
distribution source ,using the simple feedback model, receives a NACK
from another system (e.g.,an intermediary), it should redistribute
that NACK to all other systems that would not otherwise receive it. If
the distribution source, using the summary feedback model, receives a
NACK from another system, but, for some reason(e.g., to prevent
revealing the identity or existence of a system sending NACK), cannot
redistribute that NACK, then it 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. Therefore the intermediate node can be
reasonably certain that it will help the situation by sending a Third
Party Loss Report message to all the relevant receivers, thereby
indicating to the receivers that they should not transmit feedback
messages for a certain period of time. The intermediate node needs to
take into account such factors as the tolerable application delay,
packet loss recovery techniques, the network dynamics, and the media
type. Loss-repair methods such as retransmission and Forward Error
Correction may be used to recover the missing packet.</t>
<t>Alternatively, the media source may directly monitor the amount of
feedback reports it receives from downstream. If the media source
notices the loss itself, then it may send a NACK downstream towards
the receivers to suppress feedback. If the media source receives a
NACK from another system, it should redistribute that NACK to all
other systems that would not otherwise receive it. If the media source
receives a NACK from another system, but, for some reason (e.g.,
hiding identity or existing a system sending NACK ), cannot
redistribute that NACK, then it 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.</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
multicast SSM stream from the media source. If one of the BRSes
receives downstream loss report (i.e., First loss in <xref
target="fig4"></xref>) on its downstream link, but the others BRSes
have not, as the packet loss took place on the SSM tree branch that
does not impact the other BRSes. In such case, the BRSes not being
impacted are not aware of downstream loss at their downstream link,
therefore these BRSes will not create a new Third Party Loss Report
message and send it to receivers in their downstream path. If the BRS
impacted by packet loss has been told the actual packet loss, the BRS
MAY choose to create new Third Party Loss Report message and send it
to the receivers in the downstream link. Note that BRS must use its
own SSRC as packet sender SSRC for transmitting the feedback suppress
message.</t>
<t>The BRS may also send a NACK upstream to request the retransmitted
packet. Upon receiving the retransmitted packet, the BRS sent it
downstream. Note that this retransmitted packet may get lost (i.e.,
second loss in the <xref target="fig4"></xref>) on the downstream
link. In order to deal with this issue, the downstream receiver can
start a timeout clock in which it expected to get a retransmission
packet. When this timeout expires and there is no retransmitted packet
or a new Third Party Loss Report message, it can take its normal
behavior as if there is no current retransmission suppression in
place. <figure align="center" anchor="fig4" title="RAMS Use Case">
<artwork>
+------------+ First Loss +----------+
|Burst and |Second Loss | |
+-----------| Retrans. |----X--X--->| |
| Upstream |Source1(BRS)| Downstream | |
Link close | link 1 +------------+ link 1 | |
to multicast | | |
source | | |
| | | |
| | +------------+ | RTP |
+---------+ | +-----++ |Burst and | | Receiver |
|Multicast| V| | +----------| Retrans. |----------->| |
| Source +-----|Router|Upstream |Source2(BRS)| Downstream | RTP_Rx |
+---------+ | |link 2 +------------+ link 2 | |
+-----++ | |
| | |
| | |
| | |
| +------------+ | |
| |Burst and | | |
+-----------+ Retrans. |----------->| |
Upstream |Source k(BRS| Downstream | |
link k +------------+ link k +----------+
</artwork>
</figure></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
can identify packet loss using co-located monitor <xref
target="I-D.ietf-avtcore-monarch"></xref> by receiving a NACK from
another system and then the monitor can use it's own SSRC as packet
sender SSRC for transmitting the Third Party Loss Report message and
send this message to the unicast receivers that is not aware of packet
loss.</t>
</section>
<section title="Multipoint Control Unit (MCU) use case">
<t>In point to multipoint topologies using video switching MCU
(Topo-Video-switch-MCU) <xref target="RFC5117"></xref>, the MCU
typically forwards a single media stream to each participant, selected
from the available input streams. The selection of the input stream is
often based on voice activity in the audio-visual conference, but
other conference management mechanisms (like presentation mode or
explicit floor control) exist as well.</t>
<t>In this case the MCU may identify packet loss by receiving a NACK
from another system or may decide to switch to a new source. In both
cases the receiver may lose synchronization with the video stream and
may send a FIR request. If the MCU itself can detect the
mis-synchronization of the video, the MCU can send the FIR suppression
message to the receivers and send a FIR request to the video source.
As suggested in RFC 5117, this topology is better implemented as an
Topo-Mixer, in which case the mixer's SSRC is used as packet sender
SSRC for transmitting the 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 Third Party Loss Report with 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 it is authenticated via SRTCP or
similar. Accepting un-authenticated Third Party Loss Report 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>New feedback type and New parameters for RTCP Third Party Loss Report
are subject to IANA registration. For general guidelines on IANA
considerations for RTCP feedback, refer to <xref
target="RFC4585"></xref>.</t>
<t>This document assigns one new feedback type value in the RTCP
feedback report registry to "Third Party Loss Report" with the following
registrations format:</t>
<figure align="center">
<artwork>
Name: TPLR
Long Name: Third Party Loss Report
Value: TBD
Reference: This document.
</artwork>
</figure>
<t>This document also assigns the parameter value in the RTCP TPLR
feedback report Registry to " Transport Layer Third Party Loss Early
Indication ", with the following registrations format:</t>
<figure>
<artwork align="center">
Name: TLLEI
Long name: Transport Layer Third Party Loss Early Indication
Value: TBD
Reference: this document.
</artwork>
</figure>
<t>This document also assigns the parameter value in the RTCP TPLR
feedback report Registry to "Payload Specific Third Party Loss Early
Indication ", with the following registrations format:</t>
<figure align="center">
<artwork>
Name: PSLEI
Long name: Payload Specific Third Party Loss Early Indication
Value: TBD
Reference: this document.
</artwork>
</figure>
<t>The contact information for the registrations is: <figure>
<artwork>
Qin Wu
sunseawq@huawei.com
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012, China
</artwork>
</figure></t>
</section>
<section title="Acknowledgement">
<t>The authors would like to thank David R Oran, Ali C. Begen, Colin
Perkins,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.5117"?>
<?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="I-D.ietf-avtcore-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="I-D.ietf-pmol-metrics-framework">
<front>
<title>Framework for Performance Metric Development</title>
<author fullname="Alan Clark " initials="A." surname="Clark">
<organization>Telchemy Incorporated</organization>
</author>
<author fullname="B. Claise" initials="B." surname="Claise">
<organization>Cisco</organization>
</author>
<date month="January" year="2011" />
</front>
</reference>
</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:
<list style="symbols">
<t>A few Editorial changes to the whole document.</t>
</list></t>
</section>
</section>
</back>
</rfc>
| PAFTECH AB 2003-2026 | 2026-04-24 05:55:12 |