draft-ietf-xrblock-rtcp-xr-burst-gap-loss-01.txt   draft-ietf-xrblock-rtcp-xr-burst-gap-loss-02.txt 
Audio/Video Transport Working Group G. Hunt Audio/Video Transport Working Group G. Hunt
Internet-Draft Unaffiliated Internet-Draft Unaffiliated
Intended status: Standards Track A. Clark Intended status: Standards Track A. Clark
Expires: July 22, 2012 Telchemy Expires: January 11, 2013 Telchemy
S. Zhang, Ed. S. Zhang, Ed.
J. Zhao J. Zhao
STTRI STTRI
Q. Wu Q. Wu
Huawei Huawei
January 19, 2012 July 10, 2012
RTCP XR Report Block for Burst/Gap Loss metric Reporting RTCP XR Report Block for Burst/Gap Loss metric Reporting
draft-ietf-xrblock-rtcp-xr-burst-gap-loss-01.txt draft-ietf-xrblock-rtcp-xr-burst-gap-loss-02.txt
Abstract Abstract
This document defines an RTCP XR Report Block that allows the This document defines an RTCP XR Report Block that allows the
reporting of Burst and Gap Loss metrics for use in a range of RTP reporting of Burst and Gap Loss metrics for use in a range of RTP
applications. applications.
Status of this Memo Status of this Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on July 22, 2012. This Internet-Draft will expire on January 11, 2013.
Copyright Notice Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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of the metric "cumulative number of packets lost" from RTCP of the metric "cumulative number of packets lost" from RTCP
[RFC3550]. [RFC3550].
This block provides information on transient IP problems. Burst/Gap This block provides information on transient IP problems. Burst/Gap
metrics are typically used in Cumulative reports however MAY be used metrics are typically used in Cumulative reports however MAY be used
in Interval reports. The burstiness of packet loss affects user in Interval reports. The burstiness of packet loss affects user
experience, may influence any sender strategies to mitigate the experience, may influence any sender strategies to mitigate the
problem, and may also have diagnostic value. problem, and may also have diagnostic value.
The metric belongs to the class of transport-related terminal metrics The metric belongs to the class of transport-related terminal metrics
defined in [MONARCH] (work in progress). defined in [MONARCH] .
The definitions of Burst, Gap, Loss and Discard are consistent with The definitions of Burst, Gap, Loss and Discard are consistent with
definitions in [RFC3611]. To accommodate the range of jitter buffer definitions in [RFC3611]. To accommodate the range of jitter buffer
algorithms and packet discard logic that may be used by implementors, algorithms and packet discard logic that may be used by implementors,
the method used to distinguish between bursts and gaps may be an the method used to distinguish between bursts and gaps may be an
equivalent method to that defined in [RFC3611]. The method used equivalent method to that defined in [RFC3611]. The method used
SHOULD produce the same result as that defined in [RFC3611] for SHOULD produce the same result as that defined in [RFC3611] for
conditions of burst packet loss, but MAY produce different results conditions of burst packet loss, but MAY produce different results
for conditions of time varying jitter. for conditions of time varying jitter.
1.2. RTCP and RTCP XR Reports 1.2. RTCP and RTCP XR Reports
The use of RTCP for reporting is defined in [RFC3550]. [RFC3611] The use of RTCP for reporting is defined in [RFC3550]. [RFC3611]
defined an extensible structure for reporting using an RTCP Extended defined an extensible structure for reporting using an RTCP Extended
Report (XR). This draft defines a new Extended Report block that Report (XR). This document defines a new Extended Report block. The
MUST be used as defined in [RFC3550] and [RFC3611]. use of Extended Report blocks is defined by [RFC3611].
1.3. Performance Metrics Framework 1.3. Performance Metrics Framework
The Performance Metrics Framework [RFC6390] provides guidance on the The Performance Metrics Framework [RFC6390] provides guidance on the
definition and specification of performance metrics. Metrics definition and specification of performance metrics. Metrics
described in this draft either reference external definitions or described in this draft either reference external definitions or
define metrics generally in accordance with the guidelines in define metrics generally in accordance with the guidelines in
[RFC6390]. [RFC6390].
1.4. Applicability 1.4. Applicability
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Metrics in this block report on Burst/Gap Loss in the stream arriving Metrics in this block report on Burst/Gap Loss in the stream arriving
at the RTP system. at the RTP system.
3.1. Report Block Structure 3.1. Report Block Structure
Burst/Gap Loss metrics block Burst/Gap Loss metrics block
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BT=NBGL |I|C| resv. | block length = 5 | | BT=NBGL | I |C| resv. | block length = 5 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SSRC of Source | | SSRC of Source |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Threshold | Sum of Burst Durations (ms) | | Threshold | Sum of Burst Durations (ms) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Packets Lost in Bursts | Total... | | Packets Lost in Bursts | Total... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ...Packets expected in bursts | Number of bursts | Sum of| | ...Packets expected in bursts | Number of bursts | Sum of|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ...Squares of Burst Durations (ms-squared) | | ...Squares of Burst Durations (ms-squared) |
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3.2. Definition of Fields in Burst/Gap Loss Report Block 3.2. Definition of Fields in Burst/Gap Loss Report Block
Block type (BT): 8 bits Block type (BT): 8 bits
A Burst/Gap Loss Report Block is identified by the constant NBGL. A Burst/Gap Loss Report Block is identified by the constant NBGL.
[Note to RFC Editor: please replace NBGL with the IANA provided [Note to RFC Editor: please replace NBGL with the IANA provided
RTCP XR block type for this block.] RTCP XR block type for this block.]
Interval Metric flag (I): 1 bit Interval Metric flag (I): 2 bit
This field is used to indicate whether the Packet Delay Variation This field is used to indicate whether the Burst/Gap Loss metrics
metrics block is an Interval or a Cumulative report, that is, are Sampled, Interval or Cumulative metrics, that is, whether the
whether the reported values apply to the most recent measurement reported values applies to the most recent measurement interval
interval duration between successive metrics reports (I=1) (the duration between successive metrics reports (I=10) (the Interval
Interval Duration) or to the accumulation period characteristic of Duration) or to the accumulation period characteristic of
cumulative measurements (I=0) (the Cumulative Duration). cumulative measurements (I=11) (the Cumulative Duration) or is a
sampled instantaneous value (I=01) (Sampled Value).
Loss and Discard Combination flag (C): 1 bit Loss and Discard Combination flag (C): 1 bit
The 'C' flag is used to indicate whether combining loss/discard The 'C' flag is used to indicate whether combining loss/discard
report is needed. This field MUST be set to '1' if the burst gap report is needed. This field MUST be set to '1' if the burst gap
loss report is present in conjunction with the burst gap discard loss report is present in conjunction with the burst gap discard
report in the same compound RTCP packet and MUST be set to '0' report in the same compound RTCP packet and MUST be set to '0'
otherwise. If the burst gap discard is not sent with burst gap otherwise. If the burst gap discard is not sent with burst gap
loss, then the receiver should discard burst gap loss with 'C' loss, then the receiver should discard burst gap loss with 'C'
flag set to 1. If the 'C' flag is set to 0, then receiver should flag set to 1. If the 'C' flag is set to 0, then receiver should
not discard burst gap loss metric block when burst gap discard is not discard burst gap loss metric block when burst gap discard is
not received. not received.
Reserved (resv): 7 bits Reserved (resv): 5 bits
These bits are reserved. They SHOULD be set to zero by senders These bits are reserved. They SHOULD be set to zero by senders
and MUST be ignored by receivers. and MUST be ignored by receivers.
block length: 16 bits block length: 16 bits
The length of this report block in 32-bit words, minus one. For The length of this report block in 32-bit words, minus one. For
the Delay block, the block length is equal to 5. the Delay block, the block length is equal to 5.
SSRC of source: 32 bits SSRC of source: 32 bits
As defined in Section 4.1 of [RFC3611]. As defined in Section 4.1 of [RFC3611].
Threshold: 8 bits Threshold: 8 bits
The Threshold is equivalent to Gmin in [RFC3611], i.e. the number The Threshold is equivalent to Gmin in [RFC3611], i.e. the number
of successive packets that must be received prior to and following of successive packets that must be received prior to and following
a lost frame in order for this lost frame to be regarded as part a lost packet in order for this lost packet to be regarded as part
of a gap. of a gap.
Sum of Burst Durations (ms): 24 bits Sum of Burst Durations (ms): 24 bits
The total duration of bursts of lost frames in the period of the The total duration of bursts of lost packets in the period of the
report (Interval or Cumulative). report (Interval or Cumulative).
If the measured value exceeds 0xFFFFFD, the value 0xFFFFFE SHOULD If the measured value exceeds 0xFFFFFD, the value 0xFFFFFE SHOULD
be reported to indicate an over-range measurement. If the be reported to indicate an over-range measurement. If the
measurement is unavailable, the value 0xFFFFFF SHOULD be reported. measurement is unavailable, the value 0xFFFFFF SHOULD be reported.
Packets lost in bursts: 24 bits Packets lost in bursts: 24 bits
The total number of packets lost during loss bursts. The total number of packets lost during loss bursts.
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Where the metric is used with a Voice-overIP (VoIP) application, the Where the metric is used with a Voice-overIP (VoIP) application, the
following considerations apply. following considerations apply.
RTCP XR views a call as being divided into bursts, which are periods RTCP XR views a call as being divided into bursts, which are periods
during which the loss rate is high enough to cause noticeable call during which the loss rate is high enough to cause noticeable call
quality degradation (generally over 5 percent loss rate), and gaps, quality degradation (generally over 5 percent loss rate), and gaps,
which are periods during which lost packets are infrequent and hence which are periods during which lost packets are infrequent and hence
call quality is generally acceptable. call quality is generally acceptable.
If Voice Activity Detection is used the Burst and Gap Duration shall If Voice Activity Detection is used the Burst and Gap Duration shall
be determined as if silence frames had been sent, i.e. a period of be determined as if silence packets had been sent, i.e. a period of
silence in excess of Gmin frames MUST terminate a burst condition. silence in excess of Gmin packets MUST terminate a burst condition.
The recommended value for the threshold Gmin in [RFC3611] results in The recommended value for the threshold Gmin in [RFC3611] results in
a Burst being a period of time during which the call quality is a Burst being a period of time during which the call quality is
degraded to a similar extent to a typical PCM Severely Errored Second degraded to a similar extent to a typical PCM Severely Errored Second
[PSES]. [PSES].
5. SDP Signaling 5. SDP Signaling
[RFC3611] defines the use of SDP (Session Description Protocol) [RFC3611] defines the use of SDP (Session Description Protocol)
[RFC4566] for signaling the use of XR blocks. XR blocks MAY be used [RFC4566] for signaling the use of XR blocks. XR blocks MAY be used
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6.2. New RTCP XR SDP Parameter 6.2. New RTCP XR SDP Parameter
This document also registers a new parameter "brst-gap-loss" in the This document also registers a new parameter "brst-gap-loss" in the
"RTCP XR SDP Parameters Registry". "RTCP XR SDP Parameters Registry".
6.3. Contact information for registrations 6.3. Contact information for registrations
The contact information for the registrations is: The contact information for the registrations is:
Geoff Hunt (r.geoff.hunt@gmail.com) Qin Wu (sunseawq@huawei.com)
Orion 2 PP3, Adastral Park, Martlesham Heath, Ipswich IP5 3RE, United 101 Software Avenue, Yuhua District
Kingdom Nanjing, Jiangsu 210012
China
7. Security Considerations 7. Security Considerations
It is believed that this proposed RTCP XR report block introduces no It is believed that this proposed RTCP XR report block introduces no
new security considerations beyond those described in [RFC3611]. new security considerations beyond those described in [RFC3611].
This block does not provide per-packet statistics so the risk to This block does not provide per-packet statistics so the risk to
confidentiality documented in Section 7, paragraph 3 of [RFC3611] confidentiality documented in Section 7, paragraph 3 of [RFC3611]
does not apply. does not apply.
8. Contributors 8. Contributors
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