One document matched: draft-ietf-avtcore-feedback-supression-rtp-02.xml
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<rfc category="std" docName="draft-ietf-avtcore-feedback-supression-rtp-02"
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="May" year="2011" />
<workgroup>Network Working Group</workgroup>
<abstract>
<t>In a large RTP session using the RTCP feedback mechanism defined in
RFC 4585, a media source or middlebox may experience transient overload
if some event causes a large number of receivers to send feedback at
once. This feedback implosion can be mitigated if the device suffering
from overload can send a third party loss report message to the
receivers to inhibit further feedback. This memo defines RTCP Extension
for third party loss report, to suppress NACK and FIR feedback requests.
It also defines associated SDP signaling.</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 defined in 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 sending multicast NACK to
the group can not prevent large amount of unicast NACK addressed to the
same media source or middlebox, for example when the NACK is used as a
retransmission request <xref target="RFC4588"></xref>. Also 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 message 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.</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 (AVPF) and define the Third Party
Loss Report message. The Third Party Loss Report message informs the
receiver in the downstream path of the middlebox that the sender of the
Third Party Loss Report has received reports that the indicated packets
were lost and asks a receiver to not send feedback messages for
particular packets (indicated by their RTP sequence numbers) independent
of whether the receiver detected the packet loss or detected a need for
a decoder refresh point.</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 intermediates are variously referred to as
Distribution servers, MCUs, RTP translator, or RTP mixers, depending on
the precise use case. These intermediaries monitor for packet loss
upstream of themselves by checking RTP sequence numbers, just as
receivers do. These intermediate nodes need 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. Upon observing (or suspecting) an
upstream loss, the intermediary Should send 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. Upon downstream loss is reported to the intermediary, the
intermediary SHOULD send the Third Party Loss report to the other
downstream receivers which are not aware of the loss reports, to inform
those receivers of the loss and suppress their feedback. Therefore the
intermediate node can be reasonably certain that it will help the
situation by sending a Third Party Loss Report message and NACK message
to all the relevant receivers, thereby indicating to the receivers that
they should not transmit feedback messages for a period of time. </t>
<t>Alternatively, the media source may directly monitor the amount of
feedback requests it receives from downstream, and send the Third Party
Loss Report messages to the downstream receivers. </t>
<t>When a receiver gets such 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 period of time. A
receiver may still have sent a Feedback message according to the 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 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. But unlike RTCP NACK, 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 and conveys the packet
receipt/loss events at the sequence number level from the middlebox to
the receivers in the downstream path of middlebox 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 RTP middlebox that has not seen the actual
packet loss and sent to the corresponding receivers. Intermediaries
downstream of an intermediary receiving the upstream report obviously
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 received from upstream, or
send its own Third Party Loss Report message that reflects the loss they
have been told. 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 some cases where 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. In all (properly operating) cases, the risk of
increasing network congestion is decreased.</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 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 (fsei).<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 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 the
intended use cases of using 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>In order to avoid the forms of Feedback implosion described in
section 1,the distribution source should be told that the indicated
packets were lost. How the distribution source know the indicated
packets were lost is beyond of scope of this document. When one
downstream receiver reports loss, the distribution source creates a
Third Party Loss Report and sent it to all the RTP receivers, over the
multicast channel. Another possibility is when there may be multiple
distribution sources placed between the media source and the
receivers, each distribution source may send its own Third Party Loss
report to downstream receivers respectively when downstream loss is
reported to each distribution source. And also the upstream
distribution source may inform downstream distribution sources in the
path of the detected packet loss using the Third Party Loss Report
messages. In response, if the upstream Third Party Loss Report reports
the different event, the downstream distribution sources forward Third
Party Loss Report received from upstream to all the RTP receivers,
over the multicast channel. If the same event is reported both from
upstream distribution source and from downstream receiver, the
downstream distribution source may suppress creating and sending its
own report to the relevant RTP receivers. This Third Party Loss Report
message tells the receivers that the sender of the third party loss
report has received reports that the indicated packets were lost. The
distribution source then can (optionally) ask for the lost packets
from the media source or itself on behalf of all the RTP receivers.
The lost packets will either be forthcoming from distribution source,
or it irretrievably lost such that there is nothing to be gained by
the receiver sending a NACK to the media source. </t>
<t>The distribution source must be able to communicate with all group
members in order for either mechanism to be effective at suppressing
feedback.</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. The
RTCP Feedback extension for Third Party Loss Report specified in the
<xref target="sec4"></xref> of this document will work in both
Feedback models. Details of operation in each are specified below.</t>
<section title="Simple Feedback Model">
<t>In the simple Feedback Model, NACKs from the receiver observing
the loss will be reflected to the other receivers, and there's no
need for distribution source to create the third-party loss report.
The distribution source that has not seen the actual packet loss
should pass through any Third Party Loss Report message it receives
from the upstream direction.</t>
<t>This RTCP Third Party Loss Report message lets the receivers know
that the sender of the Third party Loss Report has received reports
that the indicated packets were lost and feedback for this packet
loss is not needed and should not be sent to the media source(s). If
the media source(s) are part of the SSM group for RTCP packet
reflection, the Distribution Source must filter this packet out. If
the media source(s) are not part of the SSM group for RTCP packets,
the Distribution Source must not forward this RTCP Third Party Loss
Report message to the media source(s).</t>
</section>
<section title="Distribution Source Feedback Summary Model">
<t>In the distribution source feedback summary model, there may be
multiple distribution sources who see the actual packet loss In this
section, we focus on this generic case to discuss the distribution
Source Feedback Summary Model.</t>
<t>The distribution source A must listen on the RTP channel for
data. When the distribution source A observes RTP packets from a
media source are not consecutive by checking the sequence number of
packets, the distribution source A generates the NACK message, and
then send it to receivers in the downstream path via the multicast
channel. </t>
<t>The Distribution Source B must also listen for RTCP data sent to
the RTCP port. Upon receiving the RTCP Third Party Loss Report from
the Distribution Source A, the Distribution Source B needs to check
whether it sees the same event reported both from upstream
distribution source A and downstream receiver. If the upstream Third
Party Loss Report reports the different event, the distribution
source B passes through any Third Party Loss Report message it
receives from the upstream direction. If the same event is reported
from both distribution source A and downstream receiver of
distribution source B, the distribution source B may suppress
creating and sending its own report with the same event to the
downstream RTP receiver. </t>
<t>Also the Distribution Source B may create and send its own Third
Party Loss Report described in the Section 4 to the group over the
multicast RTCP channel in response to NACKs received from
downstream. if downstream loss is reported using NACK to the
distribution source B. </t>
</section>
</section>
<section title="Unicast based Rapid Acquisition of Multicast Stream (RAMS) use case">
<t>The typical RAMS architecture <xref
target="I-D.ietf-avt-rapid-acquisition-for-rtp"></xref> may have
several Burst/Retransmission Sources(BRS) behind the multicast source
(MS) 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 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 from the upstream and send the Third Party
Loss Report message to the unicast receivers. Note that the translator
must be a participant in the session and can then use it's own SSRC as
packet sender SSRC for transmitting the Third Party Loss Report
message</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 detect packet loss from the sender 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 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 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 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 x 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 y 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 z 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="I-D.ietf-avt-rapid-acquisition-for-rtp">
<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="November" year="2010" />
</front>
</reference>
<reference anchor="I-D.hunt-avt-monarch-01">
<front>
<title>Monitoring Architectures for RTP</title>
<author fullname="Geoff Hunt" initials="G." surname="Hunt">
<organization>BT</organization>
</author>
<author fullname="Philip Arden" initials="P." surname="Arden">
<organization>BT</organization>
</author>
<date month="August" year="2008" />
</front>
</reference>
<reference anchor="I-D.ietf-pmol-metrics-framework-02">
<front>
<title>Framework for Performance Metric Development</title>
<author fullname="Alan Clark " initials="A." surname="Clark">
<organization>Telchemy Incorporated</organization>
</author>
<date />
</front>
</reference>
</references>
<section title="Appendix A. 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:
<list style="symbols">
<t>Remove the merge report from SSM use case and addional text to
address report merging issue.</t>
<t>Revise section 3 and section 6 to address FEC packet dealing
issue and Leave how to repair packet loss beyond the scope.</t>
<t>Modify the SSM use case and RAMS use case to focus on uses.</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:
<list style="symbols">
<t>In Appendix A, fix typo: Appendix A. Appendix A. ->
Appdendix A.</t>
<t>In Section 4.1, fix typo: Section 4.3.1.1 of section
[RFC5104]-> section 6.2.1 of [RFC4585].</t>
<t>In Section 3: Clarify how to deal with downstream loss using
Third party loss report and upstream loss using NACK.</t>
<t>Update title and abstract to focus on third party loss
report.</t>
<t>In Section 6.1: Update this section to explain how third party
loss report is used to deal with downstream loss.</t>
<t>In section 6.1.2: Update this section to explain how third
party loss report is used to deal with downstream loss.</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>
</back>
</rfc>
| PAFTECH AB 2003-2026 | 2026-04-24 05:55:34 |