Audio/Video Transport Working Group Q. Wu, Ed.
Internet-Draft Huawei
Intended status: Informational G. Hunt
Expires: May 17, 2012 Unaffiliated
P. Arden
BT
November 14, 2011
Monitoring Architectures for RTP
draft-ietf-avtcore-monarch-06.txt
Abstract
This memo proposes an architecture for extending RTCP with a new RTCP
XR (RFC3611) block type to report new metrics regarding media
transmission or reception quality, following RTCP guideline
established in RFC5968. This memo suggests that a new block should
contain a single metric or a small number of metrics relevant to a
single parameter of interest or concern, rather than containing a
number of metrics which attempt to provide full coverage of all those
parameters of concern to a specific application. Applications may
then "mix and match" to create a set of blocks which covers their set
of concerns. Where possible, a specific block should be designed to
be re-usable across more than one application, for example, for all
of voice, streaming audio and video.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on May 17, 2012.
Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Requirements notation . . . . . . . . . . . . . . . . . . . . 4
3. RTP monitoring architecture . . . . . . . . . . . . . . . . . 6
3.1. RTCP Metric Block Report and associated parameters . . . . 8
4. Issues with reporting metric block using RTCP XR extension . . 10
5. Guideline for reporting metric block using RTCP XR . . . . . . 12
5.1. Using single metrics blocks . . . . . . . . . . . . . . . 12
5.2. Correlating RTCP XR with the non-RTP data . . . . . . . . 12
5.3. Reducing Measurement information repetition . . . . . . . 13
6. An example of a metric block . . . . . . . . . . . . . . . . . 14
7. Application to RFC 5117 topologies . . . . . . . . . . . . . . 15
7.1. Applicability to MCU . . . . . . . . . . . . . . . . . . . 15
7.2. Applicability to Translators . . . . . . . . . . . . . . . 16
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
9. Security Considerations . . . . . . . . . . . . . . . . . . . 18
10. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 19
11. Informative References . . . . . . . . . . . . . . . . . . . . 20
Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 22
A.1. draft-ietf-avtcore-monarch-00 . . . . . . . . . . . . . . 22
A.2. draft-ietf-avtcore-monarch-01 . . . . . . . . . . . . . . 22
A.3. draft-ietf-avtcore-monarch-02 . . . . . . . . . . . . . . 22
A.4. draft-ietf-avtcore-monarch-03 . . . . . . . . . . . . . . 23
A.5. draft-ietf-avtcore-monarch-04 . . . . . . . . . . . . . . 23
A.6. draft-ietf-avtcore-monarch-05 . . . . . . . . . . . . . . 23
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 25
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1. Introduction
As more users and subscribers rely on real time application services,
uncertainties in the performance and availability of these services
are driving the need to support new standard methods for gathering
performance metrics from RTP applications. These rapidly emerging
standards, such as RTCP XR [RFC3611] and other RTCP extension to
Sender Reports (SR), Receiver Reports (RR) [RFC3550] are being
developed for the purpose of collecting and reporting performance
metrics from endpoint devices that can be used to correlate the
metrics, provide end to end service visibility and measure and
monitor Quality of Experience (QoE).
However the proliferation of RTP/RTCP specific metrics for transport
and application quality monitoring has been identified as a potential
problem for RTP/RTCP interoperability, which attempt to provide full
coverage of all those parameters of concern to a specific
application. Since different applications layered on RTP may have
some monitoring requirements in common, therefore these metrics
should be satisfied by a common design.
The objective of this document is to define an extensible RTP
monitoring framework to provide a small number of re-usable Quality
of Service (QoS)/QoE metrics which facilitate reduced implementation
costs and help maximize inter-operability. RTCP Guideline [RFC5968]
has stated that, where RTCP is to be extended with a new metric, the
preferred mechanism is by the addition of a new RTCP XR [RFC3611]
block. This memo assumes that any requirement for a new metric to be
transported in RTCP will use a new RTCP XR block.
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2. Requirements notation
This memo is informative and as such contains no normative
requirements.
In addition, the following terms are defined:
Transport level metrics
A set of metrics which characterise the three transport
impairments of packet loss, packet delay, and packet delay
variation. These metrics should be usable by any application
which uses RTP transport.
Application level metrics
Metrics relating to QoE related parameters. These metrics are
measured at the application level and focus on quality of content
rather than network parameters. One example of such metrics is
the QoE Metric specified in QoE metric reporting Block [MQ].
End System metrics
Metrics relating to the way a terminal deals with transport
impairments affecting the incident RTP stream. These may include
de-jitter buffering, packet loss concealment, and the use of
redundant streams (if any) for correction of error or loss.
Direct metrics
Metrics that can be directly measured or calculated and are not
dependent on other metric.
Composed metrics
Metrics that are calculated based on direct metric or combination
of direct metric and derived metrics.
Interval metrics
It is referred to as the metrics of which the reported values
apply to the most recent measurement interval duration between
successive metrics reports
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Cumulative metrics
It is referred to as the metrics of which the reported values
apply to the accumulation period characteristic of cumulative
measurements
Sample metrics
It is referred to as the metrics of which the reported values only
apply to the value of a continuously measured or calculated that
has been sampled at end of the interval .
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3. RTP monitoring architecture
The RTP monitoring architecture comprises the following two key
functional components shown below:
o Monitor
o Metric Block Structure
Monitor is the functional component defined in the Real-time
Transport Protocol (RTP) [RFC3550] that acts as a source of
information gathered for monitoring purposes. It may gather such
information reported by RTCP XR or other RTCP extension and calculate
statistics from multiple source. According to the definition of
monitor in the RTP Protocol [RFC3550], the end system that source RTP
streams, an intermediate-system that forwards RTP packets to End-
devices or a third party that does not participate in the RTP session
(i.e., the third party monitor depicted in figure 1) can be
envisioned to act as the Monitor within the RTP monitoring
architecture.
The Metric Block exposes real time Application QoS/QoE metric
information in the appropriate report block format to the management
system within the RTP monitoring architecture. Such information can
be formulated as:
o The direct metrics
o or the composed metrics.
or formulated as
o The Interval metrics
o or cumulative metrics
o or sample metrics.
Both the RTCP or RTCP XR can be extended to convey these metrics.
The details on transport protocols for metric blocks are described in
Section 3.1.
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+-------------------+
| RTP Sender | +----------+
| +-----------+ | |Management|
---------------->| Monitor |---------5------->| System |
| | | | | | |
| | +-----------+ | +----------+
| |+-----------------+|
| ||Application || --------------|
| ||-Streaming video || | |
| |---------|-VOIP || | +--------V------+
| | ||-Video conference|| ------ Third Party |
| | ||-Telepresence || | Monitor |
| | ||-Ad insertion || +---------------+
5 | |+-----------------+|
| | +-------------------+
| 1
| | +Intermediate------------+ |-------------- ---- ----+
| | | RTP System Report Block | RTP Receiver >--4-| |
| | | +---------- transported over| +-----------+ | |
| | | | RTCP extension | | Monitor |<-- |
|------------- Monitor |<--------5------|----| |<------|
| | | | Report Block +----/------+ ||
| | +----------+ transported over | ||
| | RTCP XR | |2 ||
| | +-----------------+ | | +-------/---------+ ||
| | |Application | | | |Application | ||
| | |-Streaming video | | | |-Streaming video | ||
| | |-VOIP | | 1 | |-VOIP | 3|
---->-Video conference|--------------->|-Video conference ||
| |-Telepresence | | | |-Telepresence | ||
| |-Ad insertion | | | |-Ad insertion | ||
| +-----------------+ | | +-----------------+ ||
| +-----------------+ | | +-----------------+ ||
| |Transport | | | |Transport | ||
| |-IP/UDP/RTP | | | |-IP/UDP/RTP >---||
| |-IP/TCP/RTP | | | | -IP/TCP/RTP | |
| |-IP/TCP/RTSP/RTP | | | |-IP/TCP/RTSP/RTP | |
| +-----------------+ | | +-----------------+ |
+------------------------+ +------------------------+
Figure 1: RTP Monitoring Architecture
1. RTP communication between real time applications.
2. Application level metrics collection.
3. Transport level metrics collection.
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4. End System metrics collection.
5. Reporting Session- metrics transmitted over specified interfaces.
3.1. RTCP Metric Block Report and associated parameters
The basic RTCP Reception Report (RR) [RFC3550] conveys reception
statistics (i.e., transport level statistics) in metric block report
format for multiple RTP media streams including
o the fraction of packet lost since the last report
o the cumulative number of packets lost
o the highest sequence number received
o an estimate of the inter-arrival jitter
o and information to allow senders to calculate the network round
trip time.
The RTCP XRs [RFC3611] supplement the existing RTCP packets and
provide more detailed feedback on reception quality in several
categories:
o Loss and duplicate RLE reports
o Packet-receipt times reports
o Round-trip time reports
o Statistics Summary Reports
There are also various other scenarios in which it is desirable to
send RTCP Metric reports more frequently. For example, the Audio/
Video Profile with Feedback [RFC4585] extends the standard A/V
Profile [RFC3551] to allow RTCP reports to be sent early provided
RTCP bandwidth allocation is respected. The following are four use
cases but are not limited to:
o RTCP NACK is used to provide feedback on the RTP sequence number
of the lost packets [RFC4585].
o RTCP is extended to convey requests for full intra-coded frames or
select the reference picture, and signalchanges in the desired
temporal/spatial trade-off and maximum media bit rate [RFC5104].
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o RTCP or RTCP XR is extended to provide feedback on ECN statistics
information [ECN].
o RTCP XR is extended to provide feedback on multicast acquisition
statistics information and parameters [RFC6332].
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4. Issues with reporting metric block using RTCP XR extension
Issues that have come up in the past with reporting metric block
using RTCP XR extensions include (but are probably not limited to)
the following:
o Using large block. A single report block or metric is designed to
contain a large number of parameters in different classes for a
specific application. For example, the RTCP Extended Reports
(XRs) [RFC3611] defines seven report block formats for network
management and quality monitoring. Some of these block types
defined in the RTCP XRs [RFC3611] are only specifically designed
for conveying multicast inference of network characteristics
(MINC) or voice over IP (VoIP) monitoring. However different
applications layered on RTP may have different monitoring
requirements. Design large block only for specific applications
may increase implementation cost and minimize interoperability.
o Correlating RTCP XR with the non-RTP data. CNAME defined in the
RTP Protocol [RFC3550] is an example of existing tool that allows
to bind an SSRC that may change to a fixed source name in one RTP
session. It may be also fixed across multiple RTP sessions from
the same source. However there may be situations where RTCP
reports are sent to other participating endpoints using non-RTP
protocol in a session. For example, as described in the SIP RTCP
Summary Report Protocol [RFC6035], the data contained in RTCP XR
VoIP metrics reports [RFC3611] are forwarded to a central
collection server systems using SIP. In such case, there is a
large portfolio of quality parameters that can be associated with
real time application,e.g., VOIP application, but only a minimal
number of parameters are included on the RTCP-XR reports.
Therefore correlation between RTCP XR and non-RTP data should be
concerned if administration or management systems need to rely on
the mapping RTCP statistics to non-RTCP measurements to conducts
data analysis and creates alerts to the users. Without such
correlation, it is hard to provide accurate measures of real time
application quality with a minimal number of parameters included
on the RTCP-XR reports in such case.
o Measurement Information duplication. Measurement information
provides information relevant to a measurement reported in one or
more other block types. For example we may set a metric interval
for the session and monitor RTP packets within one or several
consecutive metric interval. In such case, the extra meaurement
information (e.g., extended sequence number of 1st packet,
measurement period) may be expected. However if we put such extra
measurement information into each metric block, there may be
situations where an RTCP XR packet containing multiple metric
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blocks, reports on the same streams from the same source. In
other words, duplicated data for the measurement is provided
multiple times, once in every metric block. Though this design
ensures immunity to packet loss, it may bring more packetization
complexity and the processing overhead is not completely trivial
in some cases. Therefore compromise between processing overhead
and reliability should be taken into account.
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5. Guideline for reporting metric block using RTCP XR
5.1. Using single metrics blocks
Different applications using RTP for media transport certainly have
differing requirements for metrics transported in RTCP to support
their operation. For many applications, the basic metrics for
transport impairments provided in RTCP SR and RR packets [RFC3550]
(together with source identification provided in RTCP SDES packets)
are sufficient. For other applications additional metrics may be
required or at least sufficiently useful to justify the overheads,
both of processing in endpoints and of increased session bandwidth.
For example an IPTV application using Forward Error Correction (FEC)
might use either a metric of post-repair loss or a metric giving
detailed information about pre-repair loss bursts to optimise payload
bandwidth and the strength of FEC required for changing network
conditions. However there are many metrics available. It is likely
that different applications or classes of applications will wish to
use different metrics. Any one application is likely to require
metrics for more than one parameter but if this is the case,
different applications will almost certainly require different
combinations of metrics. If larger blocks are defined containing
multiple metrics to address the needs of each application, it becomes
likely that many different such larger blocks are defined, which
becomes a danger to interoperability.
To avoid this pitfall, this memo proposes the use of small RTCP XR
metrics blocks each containing a very small number of individual
metrics characterizing only one parameter of interest to an
application running over RTP. For example, at the RTP transport
layer, the parameter of interest might be packet delay variation, and
specifically the metric "IPDV" defined by [Y1540]. See Section 6 for
architectural considerations for a metrics block, using as an example
a metrics block to report packet delay variation.
5.2. Correlating RTCP XR with the non-RTP data
There may be situation where more than one media transport protocols
are used by one application to interconnect to the same session in
the gateway. For example, one RTCP XR Packet is sent to the
participating endpoints using non- RTP-based media transport (e.g.,
using SIP) in a VOIP session, one crucial factor lies in how to
handle their different identities that are corresponding to different
media transport.
This memo proposes an approach to facilitate the correlation of the
RTCP Session with other session-related non-RTP data. That is to say
if there is a need to correlate RTP sessions with non-RTP sessions,
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then the correlation information needed should be conveyed in a new
RTCP Source Description (SDES) item ,since such correlation
information describes the source, rather than providing a quality
report. An example use case is for a participant endpoint may convey
a call identifier or a global call identifier associated with the
SSRC of measured RTP stream . In such case, the participant endpoint
uses the SSRC of source to bind the call identifier using SDES item
in the SDES RTCP packet and send such correlation to the network
management system. A flow measurement tool that is configured with
the 5-tuple and not call-aware then forward the RTCP XR reports along
with the SSRC of the measured RTP stream which is included in the XR
Block header and 5-tuple to the network management system. Network
management system can then correlate this report using SSRC with
other diagnostic information such as call detail records.
5.3. Reducing Measurement information repetition
When multiple metric blocks are carried in one RTCP XR packet,
reporting on the same stream from the same source for the same time
period, RTCP should use the SSRC to identify and correlate the
multiple metric blocks between metric blocks. This memo proposes to
define a new XR Block that will be used to convey the common time
period and the number of packets sent during this period [MI]. In
order to reduce measurement information repetition in one RTCP XR
compound packet containing multiple metric blocks, the measurement
information shall be sent before the related metric blocks that are
from the same reporting interval. Note that for packet loss
robustness if the report blocks for the same interval span over more
than one RTCP packet then each must have the measurement identity
information even if though they will be the same.
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6. An example of a metric block
This section uses the example of an existing proposed metrics block
to illustrate the application of the principles set out in
Section 5.1.
The example [PDV] is a block to convey information about packet delay
variation (PDV) only, consistent with the principle that a metrics
block should address only one parameter of interest. One simple
metric of PDV is available in the RTCP RR packet as the "interarrival
jitter" field. There are other PDV metrics which may be more useful
to certain applications. Two such metrics are the IPDV metric
([Y1540], [RFC3393]) and the MAPDV2 metric [G1020]. Use of these
metrics is consistent with the principle in Section 5 of RTCP
guideline [RFC5968] that metrics should usually be defined elsewhere,
so that RTCP standards define only the transport of the metric rather
than its nature. The purpose of this section is to illustrate the
architecture using the example of [PDV] rather than to document the
design of the PDV metrics block or to provide a tutorial on PDV in
general.
Given the availability of at least three metrics for PDV, there are
design options for the allocation of metrics to RTCP XR blocks:
o provide an RTCP XR block per metric
o provide a single RTCP XR block which contains all three metrics
o provide a single RTCP block to convey any one of the three
metrics, together with a identifier to inform the receiving RTP
system of the specific metric being conveyed
In choosing between these options, extensibility is important,
because additional metrics of PDV may well be standardized and
require inclusion in this framework. The first option is extensible
but only by use of additional RTCP XR blocks, which may consume the
limited namespace for RTCP XR blocks at an unacceptable rate. The
second option is not extensible, so could be rejected on that basis,
but in any case a single application is quite unlikely to require
transport of more than one metric for PDV. Hence the third option
was chosen. This implies the creation of a subsidiary namespace to
enumerate the PDV metrics which may be transported by this block, as
discussed further in [PDV] .
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7. Application to RFC 5117 topologies
The topologies specified in [RFC5117] fall into two categories. The
first category relates to the RTP system model utilizing multicast
and/or unicast. The topologies in this category are specifically
Topo-Point-to-Point, Topo- Multicast, Topo-Translator (both variants,
Topo-Trn-Translator and Topo-Media-Translator, and combinations of
the two), and Topo-Mixer. These topologies use RTP end systems, RTP
mixers and RTP translators defined in the RTP protocol [RFC3550].
For purposes of reporting connection quality to other RTP systems,
RTP mixers and RTP end systems are very similar. Mixers
resynchronize packets and do not relay RTCP reports received from one
cloud towards other cloud(s). Translators do not resynchronize
packets and SHOULD forward certain RTCP reports between clouds. In
this category, the RTP system (end system, mixer or translator) which
originates, terminates or forwards RTCP XR blocks is expected to
handle RTCP, including RTCP XR, according to the RTP protocol
[RFC3550]. Provided this expectation is met, an RTP system using
RTCP XR is architecturally no different from an RTP system of the
same class (end system, mixer, or translator) which does not use RTCP
XR. The second category relates to deployed system models used in
many H.323 [H323] video conferences. The topologies in this category
are Topo-Video-Switch-MCU and Topo-RTCP-terminating-MCU. Such
topologies based on systems do not behave according to the RTP
protocol [RFC3550].
Considering the MCU and translator are two typical topologies in the
two categories mentioned above, this document will take them as two
typical examples to explain how RTCP XR report works in different
RFC5117 topologies.
7.1. Applicability to MCU
Topo-Video-Switch-MCU and Topo-RTCP-terminating-MCU, suffer from the
difficulties described in [RFC5117]. These difficulties apply to
systems sending, and expecting to receive, RTCP XR blocks as much as
to systems using other RTCP packet types. For example, a participant
RTP end system may send media to a video switch MCU. If the media
stream is not selected for forwarding by the switch, neither RTCP RR
packets nor RTCP XR blocks referring to the end system's generated
stream will be received at the RTP end system. Strictly the RTP end
system can only conclude that its RTP has been lost in the network,
though an RTP end system complying with the robustness principle of
[RFC1122] should survive with essential functions (i.e.,media
distribution) unimpaired.
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7.2. Applicability to Translators
Section 7.2 of the RTP protocol [RFC3550] describes processing of
RTCP by translators. RTCP XR is within the scope of the
recommendations of the RTP protocol [RFC3550]. Some RTCP XR metrics
blocks may usefully be measured at, and reported by, translators. As
described in the RTP protocol [RFC3550] this creates a requirement
for the translator to allocate an SSRC for the monitor collocated
with itself so that the monitor may populate the SSRC in the RTCP XR
packet header as packet sender SSRC and send it out(although the
translator is not a Synchronisation Source in the sense of
originating RTP media packets). It must also supply this SSRC and
the corresponding CNAME in RTCP SDES packets.
In RTP sessions where one or more translators generate any RTCP
traffic towards their next-neighbour RTP system, other translators in
the session have a choice as to whether they forward a translator's
RTCP packets. Forwarding may provide additional information to other
RTP systems in the connection but increases RTCP bandwidth and may in
some cases present a security risk. RTP translators may have
forwarding behaviour based on local policy, which might differ
between different interfaces of the same translator.
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8. IANA Considerations
At the time of writing, the consumption of XR block code points isn't
a major issue. However when XR block codes points is really close to
run out of space, it might be desirable to define new fields encoded
as TLV elements in the XR report block or define one XR block type
for vendor-specific extensions, with an enterprise number included to
identify the vendor making the extension.
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9. Security Considerations
This document focuses on the RTCP reporting extension using RTCP XR
and should not give rise to any new security vulnerabilities beyond
those described in RTCP XRs [RFC3611]. However it also describes the
architectural framework to be used for monitoring at RTP layer. The
security issues with monitoring needs to be considered.
In RTP sessions, a translator may use its own SSRC to send its
monitoring reports towards its next-neighbour RTP system. Other
translators in the session may have a choice as to whether they
forward the translator's RTCP packets. This present a security issue
since the information in the report may be exposed by the other
translator to any malicious node. Therefore if the information is
considered as sensitive, the monitoring report should be encrypted.
Also note that the third party monitors are not visible at the RTP
layer since they do not send any RTCP packets. In order to prevent
any sensitive information leakage, the monitoring from the third
party monitors should be prohibited unless the security is in place
to authenticate them.
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10. Acknowledgement
The authors would also like to thank Colin Perkins, Graeme Gibbs,
Debbie Greenstreet, Keith Drage, Dan Romascanu, Ali C. Begen, Roni
Even, Magnus Westerlundfor their valuable comments and suggestions on
the early version of this document.
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11. Informative References
[ECN] Westerlund, M., Johansson, I., Perkins, C., O'Hanlon, P.,
and K. Carlberg, "Explicit Congestion Notification (ECN)
for RTP over UDP", ID draft-ietf-avtcore-ecn-for-rtp-04,
July 2011.
[G1020] ITU-T, "ITU-T Rec. G.1020, Performance parameter
definitions for quality of speech and other voiceband
applications utilizing IP networks", July 2006.
[H323] ITU-T, "ITU-T Rec. H.323, Packet-based multimedia
communications systems", June 2006.
[MI] ITU-T, "Measurement Identity and information Reporting
using SDES item and XR Block", October 2011.
[MQ] Wu, Q., Zorn, G., Schott, R., and K. Lee, "RTCP XR Blocks
for multimedia quality metric reporting",
ID draft-wu-xrblock-rtcp-xr-quality-monitoring-02,
May 2011.
[PDV] Hunt, G., "RTCP XR Report Block for Packet Delay Variation
Metric Reporting", ID draft-ietf-xrblock-rtcp-xr-pdv-00,
September 2011.
[RFC1122] Braden, R., "Requirements for Internet Hosts --
Communication Layers", RFC 1122, October 1989.
[RFC3393] Demichelis, C., "IP Packet Delay Variation Metric for IP
Performance Metrics (IPPM)", RFC 3393, November 2002.
[RFC3550] Schulzrinne, H., "RTP: A Transport Protocol for Real-Time
Applications", RFC 3550, July 2003.
[RFC3551] Schulzrinne , H. and S. Casner, "Extended RTP Profile for
Real-time Transport Control Protocol (RTCP)-Based Feedback
(RTP/AVPF)", RFC 3551, July 2003.
[RFC3611] Friedman, T., "RTP Control Protocol Extended Reports (RTCP
XR)", RFC 3611, November 2003.
[RFC4585] Ott, J. and S. Wenger, "Extended RTP Profile for Real-time
Transport Control Protocol (RTCP)-Based Feedback (RTP/
AVPF)", RFC 4585, July 2006.
[RFC5104] Wenger, S., Chandra, U., Westerlund, M., and B. Burman,
"Session Initiation Protocol Event Package for Voice
Wu, et al. Expires May 17, 2012 [Page 20]
Internet-Draft RTP Monitoring Architectures November 2011
Quality Reporting", RFC 5104, February 2008.
[RFC5117] Westerlund, M., "RTP Topologies", RFC 5117, January 2008.
[RFC5968] Ott, J. and C. Perkins, "Guidelines for Extending the RTP
Control Protocol (RTCP)", RFC 5968, September 2010.
[RFC6035] Pendleton, A., Clark, A., Johnston, A., and H. Sinnreich,
"Session Initiation Protocol Event Package for Voice
Quality Reporting", RFC 6035, November 2010.
[RFC6332] Begen, A. and E. Friedrich, "Multicast Acquisition Report
Block Type for RTP Control Protocol (RTCP) Extended
Reports (XRs)", RFC 6332, July 2011.
[Y1540] ITU-T, "ITU-T Rec. Y.1540, IP packet transfer and
availability performance parameters", November 2007.
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Internet-Draft RTP Monitoring Architectures November 2011
Appendix A. Change Log
Note to the RFC-Editor: please remove this section prior to
publication as an RFC.
A.1. draft-ietf-avtcore-monarch-00
The following are the major changes compared to
draft-hunt-avtcore-monarch-02:
o Move Geoff Hunt and Philip Arden to acknowledgement section.
A.2. draft-ietf-avtcore-monarch-01
The following are the major changes compared to 00:
o Restructure the document by merging section 4 into section 3.
o Remove section 4.1,section 5 that is out of scope of this
document.
o Remove the last bullet in section 6 and section 7.3 based on
conclusion of last meeting.
o Update figure 1 and related text in section 3 according to the
monitor definition in RFC3550.
o Revise section 9 to address monitor declaration issue.
o Merge the first two bullet in section 6.
o Add one new bullet to discuss metric block association in section
6.
A.3. draft-ietf-avtcore-monarch-02
The following are the major changes compared to 01:
o Deleting first paragraph of Section 1.
o Deleting Section 3.1, since the interaction with the management
application is out of scope of this draft.
o Separate identity information correlation from section 5.2 as new
section 5.3.
o Remove figure 2 and related text from section 5.2.
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o Editorial changes in the section 4 and the first paragraph of
section 7.
A.4. draft-ietf-avtcore-monarch-03
The following are the major changes compared to 02:
o Update bullet 2 in section 4 to explain the ill-effect of Identity
Information duplication.
o Update bullet 3 in section 4 to explain why Correlating RTCP XR
with the non-RTP data is needed.
o Update section 5.2 to focus on how to reduce the identity
information repetition
o Update section 5.3 to explain how to correlate identity
information with the non-RTP data
A.5. draft-ietf-avtcore-monarch-04
The following are the major changes compared to 03:
o Update section 5.2 to clarify using SDES packet to carry
correlation information.
o Remove section 5.3 since additional identity information goes to
SDES packet and using SSRC to identify each block is standard RTP
feature.
o Swap the last two paragraphs in the section 4 since identity
information duplication can not been 100% avoided.
o Other editorial changes.
A.6. draft-ietf-avtcore-monarch-05
The following are the major changes compared to 04:
o Replace "chunk" with "new SDES item".
o Add texts in security section to discussion potential security
issues.
o Add new sub-section 5.3 to discuss Reducing Measurement
information repetition.
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o Other editorial changes.
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Authors' Addresses
Qin Wu (editor)
Huawei
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012
China
Email: sunseawq@huawei.com
Geoff Hunt
Unaffiliated
Email: r.geoff.hunt@gmail.com
Philip Arden
BT
Orion 3/7 PP4
Adastral Park
Martlesham Heath
Ipswich, Suffolk IP5 3RE
United Kingdom
Phone: +44 1473 644192
Email: philip.arden@bt.com
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