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Itu telecommunication Standardization Sector avd 2356 study group 16


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ITU - Telecommunication Standardization Sector AVD - 2356

STUDY GROUP 16


Q.D, F, G, 1-5/16 Rapporteur Meeting
Paris, 2 – 5 September 2003
Question(s): 3/16
SOURCE*: Nortel Networks USA

TITLE: Proposed H.248 RTCPXR Packages

___________________

Introduction:


This contribution proposes new packages to enable collection and reporting of extended QoS metrics using H.248.

Discussion:

These packages contain an improved set of Voice over IP call performance metrics. These metrics are consistent with those defined in IETF RFCxxxx (RFC number pending), RTP Control Protocol Reporting Extensions (RTCP XR). The use of a common set of metrics for QoS reporting via call control protocols and media path protocols lowers the complexity of end-systems and makes it easier to compare data when resolving service quality problems.

These metrics are easily represented utilizing statistics in an H.248 package. The package proposed by the contribution is a natural extension of the RTCP XR work that has progressed in the IETF, and the proposal of new pacakge to report these same metrics.

Proposal:


It is proposed to accept a work item in SG16 Question 3 for RTCP XR and the following package as a baseline for a RTCPXR package.
H.248.rtcpxr
RTCP Extended Performance Metrics Package

1Summary


This document defines a package that provides RTCP XR metrics reporting capabilities for H.248.

2Scope


This document describes a set of Extended Performance Metrics for Voice over IP QoS reporting that provide more detailed insight into call quality and causes of degradation than basic RTCP statistics. The metrics described in this document are consistent with those described in the RTCP XR Voice over IP Metrics Payload described in IETF RFCnnnn.

3References


The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; all users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published.

ITU-T Recommendation H.248.1 (05/2002), Gateway Control Protocol

ITU-T Recommendation G.107 (05/2000), The E-Model, a computational model for use in transmission planning

ITU-T Recommendation G.108 (09/1999), Application of the E-Model: A planning guide

IETF RFCnnnn, RTP Control Protocol Extended Reports (RTCP XR)

4Definitions


-

5Abbreviations


MG Media Gateway

MGC Media Gateway Controller

MOSCQ Mean Opinion Score for Conversational Quality

MOSLQ Mean Opinion Score for Listening Quality

RTCP RTP Control Protocol

RTCP XR RTCP Extended Reports

RTP Real-time Transfer Protocol

6RTCP XR Base Package


PackageID: rtcpxr (0x00??)
Version: 1
Extends: rtp version 1

This package defines properties and statistics to report extended quality of service metrics.


6.1Properties

6.1.1Packet Loss Concealment Type


PropertyID: plc (0x0001)
Description: The type of packet loss concealment algorithm in use.

Type: Enumeration


Possible Values: "U" (0x0001) Unspecified (Default)
"D" (0x0002) Disabled – silence insertion is being used
"S" (0x0003) Standard
"E" (0x0004) Enhanced
Defined In: LocalControl
Characteristics: Read/Write

6.2Events


None

6.3Signals


None

6.4Statistics

6.4.1Network Packet Loss Rate


StatisticID: nplr (0x0001)
Description: The proportion of packets lost since the start of transmission expressed as an 8 bit binary fraction obtained by dividing the number of packets lost in the transmission path by the total number of packets expected and multiplying this value by 256 and taking the integer part. Thus a value of 0 would correspond to a packet loss rate of zero and a value of 64 would correspond to a packet loss rate of 0.25 (corresponding to 25 percent).

Type: Integer


Possible Values: any non-negative value

6.4.2Jitter Buffer Discard Rate


StatisticID: jdr (0x0002)
Description: The proportion of packets discarded by the receiving jitter buffer since the start of transmission expressed as an 8 bit binary fraction obtained by dividing the number of packets discarded by the total number of packets expected and multiplying this value by 256 and taking the integer part.

Type: Integer


Possible Values: any non-negative value

6.4.3RTCP Round Trip Delay


StatisticID: rtd (0x0003)
Description: The round trip delay between RTP instances.

Type: Integer


Possible Values: any non-negative number of milliseconds

6.4.4End System Delay


StatisticID: esd (0x0004)
Description: The end system delay, comprising encode, decode and jitter buffer delay. This may be combined with the RTCP Round Trip Delay to estimate the overall Voice over IP segment round trip delay.

Type: Integer


Possible Values: Any non-negative number of milliseconds

6.4.5Signal Level


StatisticID: sl (0x0005)
Description: The ratio of the signal level to a 0 dBm0 reference..

Type: Integer


Possible Values: Any value in dBm0

6.4.6Noise Level


StatisticID: nl (0x0006)
Description: The ratio of the silent period background noise level to a 0 dBm0 reference.

Type: Integer


Possible Values: Any non-positive value in dBm0

6.4.7Residual Echo Return Loss


StatisticID: rerl (0x0007)
Description: The echo return loss after the effects of echo cancellation.

Type: Integer


Possible Values: Any non-negative number of dB.

6.4.8R Factor


StatisticID: ns (0x0008)
Description: A value representing the receiving end call quality of this stream, calculated per ITU-T Recommendation G.107. Table 1 in ITU-T Recommendation G.108 provides interpretive information about the value of the R factor.

Type: Integer


Possible Values: Any value between 0 and 100

6.4.9External R Factor


StatisticID: ns (0x0009)
Description: A value representing the effects of an externally connected network, calculated per ITU-T Recommendation G.107. Table 1 in ITU-T Recommendation G.108 provides interpretive information about the value of the R factor.

Type: Integer


Possible Values: Any value between 0 and 100

6.4.10Estimated MOSLQ


StatisticID: lq (0x000a)
Description: An estimated receiving end Listening Quality MOS, calculated per ITU-T Recommendation G.107 and multiplied by 10.

Type: Integer


Possible Values: Any value between 10 to 50

6.4.11Estimated MOSCQ


StatisticID: cq (0x000b)
Description: An estimated receiving end Conversational Quality MOS, calculated per ITU-T Recommendation G.107 and multiplied by 10.

Type: Integer


Possible Values: Any value between 10 and 50

6.5Procedures


None

7RTCP XR Burst Metrics Package


PackageID: xrbm (0x00??)
Version: 1
Extends: rtcpxr version 1

This package defines properties and statistics for reporting burst metrics.


7.1Properties

7.1.1Minimum Gap Threshold


PropertyID: gmin (0x0002)
Description: A parameter used to define bursts. This is by default set to 16, which sets the threshold packet loss rate between bursts and gaps to approximately 6%. See the procedures for how to use Gmin to determine a burst.

Type: Integer


Possible Values: Any positive integral value, defaults to 16
Defined In: LocalControl
Characteristics: Read/Write

7.2Events


None

7.3Signals


None

7.4Statistics

7.4.1Burst Loss Density


StatisticID: bld (0x000c)
Description: The average proportion of packets both lost and discarded during burst periods expressed as an 8 bit binary fraction. This is obtained by dividing the sum of the number of packets lost in the transmission path and discarded by the jitter buffer during burst periods by the total number of packets expected during burst periods, multiplying this value by 256 and taking the integer part.

A burst is a period during which a high proportion of packets are either lost in transit or discarded due to late arrival. In general, a burst is likely to result in audible degradation to call quality.

Type: Integer
Possible Values: any non-negative integral value

7.4.2Burst Duration


StatisticID: bd (0x000d)
Description: The average length of burst periods.
Type:
Possible Values: any non-negative integral number of milliseconds

7.4.3Gap Loss Density


StatisticID: gld (0x000e)
Description: The average proportion of packets lost and discarded during gap periods expressed as an 8 bit binary fraction. This is obtained by dividing the sum of the number of packets lost in the transmission path and discarded by the jitter buffer during gap periods by the total number of packets expected during gap periods, multiplying this value by 256 and taking the integer part.

Type: Integer


Possible Values: any non-negative integral value

7.4.4Gap Duration


StatisticID: gd (0x000f)
Description: The average length of gap periods.

Type: Integer


Possible Values: any non-negative integral number of milliseconds

7.5Procedures


A burst is defined as a longest sequence that (a) starts with a lost or discarded packet, (b) does not contain any occurrences of Gmin or more consecutive received (and not discarded) packets, and (c) ends with a lost or discarded packet.

A gap is a period between bursts; the above burst definition means that during gaps the packet loss rate is low and lost/discarded packets are isolated and hence can be effectively masked by packet loss concealment algorithms.


8Jitter Buffer Package


PackageID: jit (0x00??)
Version: 1
Extends: none

This package defines properties for setting .


8.1Properties

8.1.1Jitter Buffer Type


PropertyID: type (0x0001)
Description: Indicates the receiving jitter buffer’s type.

Type: Enumeration


Possible Values: "U" (0x0001) Unknown (Default)
"N" (0x0002) Nonadaptive
"A" (0x0003) Adaptive
Defined In: LocalControl
Characteristics: Read/Write

8.1.2Adaptation Rate


PropertyID: ar (0x0002)
Description: The adaptation rate for adaptive jitter buffers. This is defined as the time taken in milliseconds adjusting to a step from 30 ms to 100 ms in peak-to-peak jitter divided by twice the frame size in milliseconds. This property shall be 0 for non-adaptive jitter buffers.

Type: Integer


Possible Values: Any non-negative number
Defined In: LocalControl
Characteristics: Read Only

8.1.3Nominal Jitter Buffer Size


PropertyID: nom (0x0003)
Description: The current nominal jitter buffer size.

Type: Integer


Possible Values: Any non-negative number of milliseconds
Defined In: LocalControl
Characteristics: Read/Write

8.1.4Maximum Jitter Buffer Size


PropertyID: max (0x0004)
Description: The current maximum jitter buffer size.

Type: Integer


Possible Values: Any non-negative number of milliseconds
Defined In: LocalControl
Characteristics: Read/Write

8.1.5Absolute Maximum Jitter Buffer Size


PropertyID: abmax (0x0005)
Description: The maximum achievable jitter buffer size attainable for adaptive jitter buffers. This property shall be 0 for non-adaptive jitter buffers.

Type: Integer


Possible Values: Any positive integral value, defaults to 16
Defined In: LocalControl
Characteristics: Read Only

8.2Events


None

8.3Signals


None

8.4Statistics


None

8.5Procedures


None

END

____________________

* Contact:

Kevin J. Boyle II
Nortel Networks USA

Tel: +1 919 991 2690

Fax:


E-mail: kboyle@nortelnetworks.com





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