ETSI TS 101 329-3 V2.1.2 (2002-01)

SLOVENSKI STANDARD
01-april-2004
Harmonizacija telekomunikacij in internetnega protokola prek omrežij (TIPHON), 3.
izdaja - Kakovost storitve od konca do konca v sistemih TIPHON - 3. del:
Signalizacija in krmiljenje kakovosti storitve (QoS) od konca do konca
Telecommunications and Internet Protocol Harmonization Over Networks (TIPHON)
Release 3; End-to-end Quality of Service in TIPHON systems; Part 3: Signalling and
control of end-to-end Quality of Service (QoS)
Ta slovenski standard je istoveten z: ETSI TS 101 329-3 V2.1.2 (2002-01)
ICS:
33.040.30 Komutacijski in signalizacijski Switching and signalling
sistem systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

Technical Specification
Telecommunications and Internet Protocol
Harmonization Over Networks (TIPHON) Release 3;
End-to-end Quality of Service in TIPHON systems;
Part 3: Signalling and control of end-to-end
Quality of Service (QoS)
2 ETSI TS 101 329-3 V2.1.2 (2002-01)

Reference
RTS/TIPHON-05003 [2]a
Keywords
internet, network, interoperability, protocol, QoS,
telephony, IP, quality, service, signalling
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ETSI
3 ETSI TS 101 329-3 V2.1.2 (2002-01)
Contents
Intellectual Property Rights.5
Foreword.5
Introduction .6
1 Scope.7
2 References.7
3 Definitions and abbreviations.7
3.1 Definitions.7
3.2 Abbreviations.8
4 Void.9
5 QoS architecture.9
5.1 TIPHON architectural planes .9
5.1.1 IP telephony application plane.9
5.1.2 IP transport plane.9
5.1.3 Management plane.9
5.2 Service and transport domains.10
5.2.1 Void.10
5.2.2 Void.10
5.2.3 End-to-end QoS control .10
5.2.3.1 IP application plane control.10
5.2.3.2 Transport plane control .11
5.3 QoS Functional Elements.12
5.3.1 QoS Service Manager (QoSM).12
5.3.2 QoS Policy Element (QoSPE) .12
5.3.3 Transport Resource Manager (TRM).12
5.3.4 Transport Policy Entity (TPE) .12
5.3.5 Interconnect Function (ICF).12
5.3.6 Transport Function (TF) .12
5.3.7 Relationship between functional entities .13
5.4 QoS reference points .13
5.4.1 Reference point QC1 .13
5.4.2 Reference point QC2 .13
5.4.3 Reference point QS4.13
5.4.4 Reference point QT2.13
5.4.5 Reference point QT1.14
5.4.6 Reference point QI1.14
5.4.7 Reference point QI2.14
5.4.8 Reference point QI3.14
5.4.9 Reference point QI4.14
5.4.10 Reference point QI5.14
6 Characterizing QoS.14
6.1 Service, application and transport level QoS parameters .14
6.2 Interfacing to the Transport Plane .15
6.2.1 Transport QoS parameters .16
6.2.2 Traffic descriptor.17
7 Allocating the QoS budget across service and transport domains.17
7.1 Dynamic signalling of Transport QoS Parameters .18
7.2 Specification of transport QoS parameters in Service Level Agreements (SLA).18
7.3 Aggregation.19
7.3.1 Aggregation under control of the TRM .19
7.3.2 Aggregation under control of the QoSM .19
8 QoS Primitives.20
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4 ETSI TS 101 329-3 V2.1.2 (2002-01)
8.1 QoS Primitives.20
8.1.1 QC1and2.20
8.1.2 QS4.21
8.1.3 QT2.21
8.1.4 QT1.21
8.1.5 QI1.22
8.1.6 QI2.22
8.1.7 QI3.22
8.1.8 QI4.23
8.1.9 QI5.23
8.2 QoS Parameters Groups .24
8.2.1 QoS parameter groups.24
8.2.2 QC1.25
8.2.3 QC2.25
8.2.4 QS4.25
8.2.5 QT2.26
8.2.6 QT1.26
8.2.7 QI1.26
8.2.8 QI2.26
8.2.9 QI3.27
8.2.10 QI4.27
8.2.11 QI5.27
9 QoS Procedures (Informational) .27
9.1 Third Party Establishment of QoS Controlled Bearer .27
9.2 First Party Establishment of QoS Controlled Bearer.30
9.3 Hybrid Third Party/First Party Establishment of QoS controlled bearer via authorization tokens.33
9.4 Terminal Registration.36
Annex A (informative): Examples of end-to-end QoS control.37
A.1 One service domain/One transport domain .37
A.2 One service domains/multiple transport domains - Case I.38
A.3 One service domain/multiple transport domains - Case II .39
A.4 Multiple service domains/multiple transport domains .40
A.5 Multiple service domains/multiple transport domains .40
A.6 Roaming.41
A.7 Provisioned VPN.42
Annex B (informative): Examples of Mapping of QoS Architecture Functional Elements to
Physical Elements .43
Annex C (informative): Bibliography.44
History .45

ETSI
5 ETSI TS 101 329-3 V2.1.2 (2002-01)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (http://webapp.etsi.org/IPR/home.asp).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Foreword
This Technical Specification (TS) has been produced by ETSI Project Telecommunications and Internet Protocol
Harmonization Over Networks (TIPHON).
The present document is part 3 of a multi-part deliverable covering End-to-end Quality of Service in TIPHON systems,
as identified below:
TR 101 329-1: "General aspects of Quality of Service (QoS)";
TS 101 329-2: "Definition of speech Quality of Service (QoS) classes";
TS 101 329-3: "Signalling and control of end-to-end Quality of Service (QoS)";
TS 101 329-5: "Quality of Service (QoS) measurement methodologies";
TR 101 329-6: "Actual measurements of network and terminal characteristics and performance parameters in
TIPHON networks and their influence on voice quality";
TR 101 329-7: "Design guide for elements of a TIPHON connection from an end-to-end speech transmission
performance point of view".
Quality of Service aspects of TIPHON Release 4 and 5 Systems will be covered in TS 102 024 and TS 102 025
respectively, and more comprehensive versions of the Release 3 documents listed above will be published as part of
Release 4 and 5 as work progresses.
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6 ETSI TS 101 329-3 V2.1.2 (2002-01)
Introduction
The present document forms one of a series of technical specifications and technical reports produced by TIPHON
Working Group 5 addressing Quality of Service (QoS) in TIPHON Systems. The structure of this work is illustrated in
figure 1.
Introduction Definition of 5
Speech Classes
TR 101 329-1 TS 101 329-2
General Speech
QoS
Aspects
of QoS Classes
SPEC
REPORT
Generic QoS
Specific Aspects of QoS
TS 101 329-5 TR 101 329-6 TR 101 329-7
TS 101 329-3
Design
QoS Measure- Actual
Control ment Test Guidelines
Methods Results
REPORT REPORT
SPEC SPEC
Useful info for
QoS signalling Measurement Repository of
requirements methodologies real test results designers

Figure 1: Structure of TIPHON QoS Documentation for Release 3
The present document, describes a framework for the signalling and control of end-to-end Quality of Service in
TIPHON Systems.
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7 ETSI TS 101 329-3 V2.1.2 (2002-01)
1 Scope
The present document describes a framework for enabling the end-to-end QoS levels defined in TS 101 329-2 [1] to be
signalled and controlled in TIPHON systems. The mechanisms involved operate between TIPHON terminals, IP
telephony Service Providers (ITSPs), and network transport systems, and provide a flexible means for the dynamic
allocation of QoS parameters across these entities in order to meet the QoS Service Classes defined in TS 101 329-2 [1].
The functional entities involved in the QoS signalling and control are defined, as are the requirements of the reference
points between these functional entities. The QoS parameters and information flows used to establish the required
Service QoS levels are also specified.
The Application Plane mechanisms described in the present document are intended to be independent of the transport
QoS mechanisms used within the underlying IP networks.
The emphasis of the present document is on media QoS (primarily voice, but the mechanisms are also applicable to
other media types). Issues related to performance of the signalling channels are outside the scope of the present
document.
TS 101 314 [2] describes how this QoS framework fits into the overall TIPHON architecture and details of the
signalling involved are described in TS 101 471 [3].
2 References
The following documents contain provisions which, through reference in this text, constitute provisions of the present
document.
• References are either specific (identified by date of publication and/or edition number or version number) or
non-specific.
• For a specific reference, subsequent revisions do not apply.
• For a non-specific reference, the latest version applies.
[1] ETSI TS 101 329-2: "Telecommunications and Internet Protocol Harmonization Over Networks
(TIPHON) Release 3; End-to-end Quality of Service (QoS) in TIPHON systems; Part 2: Definition
of speech Quality of Service (QoS) classes".
[2] ETSI TS 101 314: "Telecommunications and Internet Protocol Harmonization Over Networks
(TIPHON); Network architecture and reference configurations; TIPHON Release 2".
[3] ETSI TS 101 471: "Telecommunications and Internet Protocol Harmonization Over Networks
(TIPHON); Signalling for calls between an H.323 terminals and terminals in a Switched-Circuit
Network (SCN); Phase III: Scenario 1, 2, 3, and 4".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
IP Telephony Service Provider (ITSP): service provider providing IP telephony services
NOTE: The same business entity may act as both a Transport Network Operator and an IP Telephony Service
Provider.
InterConnect Function (ICF): functional entity that interconnects Transport Domains
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8 ETSI TS 101 329-3 V2.1.2 (2002-01)
NOTE: It provides a policy and/or administrative boundary and may police authorized media flows between two
Transport Domains to ensure they are consistent with the QoS policy specified by the relevant Transport
Resource Manager
Quality of Service Manager (QoSM): functional entity that mediates requests for end-to-end QoS in accordance with
policy determined by the QoSPE
NOTE: It communicates with, other QoSMs and with TRMs to determine, establish and control the offered QoS.
Quality of Service Policy Element (QoSPE): functional entity that manages IP Telephony QoS policies and provides
authorization of permitted and default QoS levels
NOTE: It receives requests from and issues responses to QoSMs to establish the authorized end-to-end QoS
levels.
service domain: collection of physical or functional entities offering IP telephony services under the control of an IP
telephony service provider which share a consistent set of policies and common technologies
Transport Domain (TD): collection of transport resources sharing a common set of policies, QoS mechanisms and
transport technologies under the control of a transport network operator
transport network: collection of transport resources which provide transport functionality
transport network operator: business entity operating a Transport Network
Transport Policy Entity (TPE): functional entity that maintains the policies of a Transport Domain
Transport Resource Manager (TRM): functional entity that applies a set of policies and mechanisms to a set of
transport resources to ensure that those resources are allocated such that they are sufficient to enable QoS guarantees
across the domain of control of the TRM
Transport Function (TF): functional entity representing the collection of transport resources within a Transport
Domain which are capable of control by a Transport Resource Manager (TRM)
User Equipment (UE): equipment under the control of an End-User
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
ATM Asynchronous Transfer Mode
BC Bearer Control
CBR Constant Bit Rate
DiffServ Differentiated Services
ICF InterConnect Function
IntServ Integrated Services
IP Internet Protocol
ITSP IP Telephony Service Provider
MPLS Multi Protocol Label Switching
QoS Quality of Service
QoSM Quality of Service Manager
QoSPE Quality of Service Policy Element
RMS Root Mean Square
RSVP Resource Reservation Set-up Protocol
RTP Real-time Transport Protocol
SCN Switched Communications Network
SLA Service Level Agreement
TD Transport Domain
TF Transport Function
TPE Transport Policy Element
TRM Transport Resource Manager
UDP User Datagram Protocol
UE User Equipment
VBR Variable Bit Rate
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9 ETSI TS 101 329-3 V2.1.2 (2002-01)
VPN Virtual Private Network
4 Void
5 QoS architecture
5.1 TIPHON architectural planes
The Generalized TIPHON Architecture is shown in figure 2 (see TS 101 314 [2]).
SCN Plane
Transport plane
Transport plane
IP Telephony Application Plane
IP Transport Plane
Figure 2: Generalized TIPHON Architecture
End-to-end QoS signalling and control will in general involve QoS information flows in each of the architectural
planes.
The Required end-to-end QoS levels are established within the IP Telephony Application Plane between End-Users and
Service Provider(s). Decisions determining QoS, specific to the application, will take place in the IP Telephony
Application Plane (e.g. codec type, packetization, etc).
The IP Transport Plane (IP Network Operators) provides a QoS service to the Application Plane (Service Providers).
QoS control within the IP Transport Plane is the responsibility of the IP Network Operators.
5.1.1 IP telephony application plane
Within this plane, QoS parameters specific to the application are requested, authorized, signalled, controlled and
accounted.
5.1.2 IP transport plane
Within this plane, general non-application specific parameters effecting QoS must be controlled and accounted to
achieve the QoS requirements requested by the application.
5.1.3 Management plane
Within this plane QoS management entities applicable to both application and transport planes will reside and
information flows applicable to QoS management will terminate.
ETSI
Management Plane
10 ETSI TS 101 329-3 V2.1.2 (2002-01)
5.2 Service and transport domains
A TIPHON-compliant deployment will in the general case be made up of a number of separate Service and End-User
Domains, each representing the domain of control of an ITSP or End-User. These domains will generally be restricted
to IP Telephony Application plane functionality, e.g. gatekeepers, softswitches, call agents, etc.
Similarly, a TIPHON-compliant system will, in general, also be made up of a number of separate Transport Domains.
Transport Domains consist solely of transport related functionality; this includes IP routers and switches, firewalls, etc.
Each Transport Domain may have its own QoS policies and/or differ from other domains in terms of administrative
control (e.g. Network Operator), QoS mechanisms (RSVP/IntServ, DiffServ, MPLS), access, metering, addressing
schemes (global, local) and transport protocol (IPv4, IPv6), etc.
Since these policies are local, functional entities are needed to interface to other domains. These entities are called
InterConnect Functions.
The general TIPHON deployment is illustrated in figure 3.
5.2.1 Void
5.2.2 Void
5.2.3 End-to-end QoS control
End-to-end QoS control across multiple domains may be achieved in one of two ways:
• by having an IP Telephony Application Service Domain control each Transport Domain. The Service Domain
would request the transport resources with QoS from each of the Transport Domains and establish the
interconnect in a controlled fashion;
• by means of end-to-end signalling within and between Transport Domains which share common policies.
These two mechanisms are explained hereafter.
5.2.3.1 IP application plane control
In this first case, the routing of the call between Transport Domains is under the control of the ITSPs. In this general
case, where the Transport Plane is made up of a number of heterogeneous Transport Domains, each domain may have
its own QoS mechanisms and policies.
Figure 3 illustrates the general case where a number of separate ITSPs and Transport Domains are involved in a call.
Call-Control signalling takes place in the IP Telephony Application Plane between ITSPs, and between End-Users and
ITSPs.
Transport flows are between End-Users and transport domains, and between transport domains.
QoS signalling and SLAs are between End-Users and ITSPs, and between ITSPs and follow Call Routing. Between
each ITSP involved in the call and its associated Transport Domain(s) QoS SLAs then ensure that the required QoS
parameters are met by each Transport Domain involved in the call.
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11 ETSI TS 101 329-3 V2.1.2 (2002-01)
Service
Domain 2
Service Service
Domain 1 Domain 3
Application Plane
Transport Plane
Transport
Domain 1
Transport
Transport
Domain 3
Domain 2
Transport Flow
QoS Signalling
Call Signalling
Figure 3: Generalized TIPHON Architecture with Service Domain End-to-end QoS Control
5.2.3.2 Transport plane control
In this case, the QoS control of the call between Transport Domains is performed by the local Transport Domain and by
agreement between Transport Network Operators. QoS SLAs are required between End-Users and ITSPs and between
Transport Network Operators. The End-Users may first register with their ITSP and receive authorization to make a call
before establishing a media connection with the local Transport Network Operator.
This approach is a viable option where the Transport Plane comprises a single homogeneous policy space. Addressing,
Access and QoS mechanisms and policies all have to be uniform for this case to work.
Figure 4 illustrates the case where end-to-end control of QoS is performed by signalling in the transport plane with QoS
authorization by the access Service Provider.
Service
Domain 1
Application Plane
Transport Plane
Common Policy Space
Transport
Transport
Domain 1
Transport Domain 3
Domain 2
Transport Flow
QoS Signalling
Call Signalling
Figure 4: Generalized TIPHON architecture with transport plane End-to-end QoS control
Hybrid situations are possible where a Service Domain may control several Transport Domains or one Transport
Domain may control others. Some of these configurations are shown in annex A.
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12 ETSI TS 101 329-3 V2.1.2 (2002-01)
5.3 QoS Functional Elements
The TIPHON QoS mechanisms have elements in both the Transport and in the IP Telephony Application plane.
The following Functional Elements are involved in the QoS Control Framework.
5.3.1 QoS Service Manager (QoSM)
A functional entity that mediates requests for end-to-end QoS in accordance with policy determined by the QoSPE. It
communicates with other QoSMs and with TRMs to determine, establish and control the offered QoS.
5.3.2 QoS Policy Element (QoSPE)
A functional entity that manages IP Telephony QoS policies and provides authorization of permitted and default QoS
levels. It receives requests from and issues responses to QoSMs to establish the authorized end-to-end QoS levels.
5.3.3 Transport Resource Manager (TRM)
A functional entity that applies a set of policies and mechanisms to a set of transport resources to ensure that those
resources are allocated such that they are sufficient to enable QoS guarantees across the domain of control of the TRM.
5.3.4 Transport Policy Entity (TPE)
A functional entity that maintains the policies of a Transport Domain.
5.3.5 Interconnect Function (ICF)
A functional entity that interconnects Transport Domains. It provides a policy and/or administrative boundary and may
police authorized transport flows between two Transport Domains to ensure they are consistent with the QoS policy
specified by the relevant Transport Resource Manager.
5.3.6 Transport Function (TF)
A functional entity representing the collection of transport resources within a Transport Domain which are capable of
control by a Transport Resource Manager
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13 ETSI TS 101 329-3 V2.1.2 (2002-01)
5.3.7 Relationship between functional entities
The relationship between these QoS Functional Entities is shown in figure 5.
QoSPE
End User
Service
Domain
Domain
QS4
Other
QoSM QoSM
Service Domains
QC1 QC2
Application Plane
QT1
Transport Plane QT2 QT2
End User
Transport Domain Transport Domain
Transport Domain
QI4 QI4
QI4
TPE
TPE
TPE
QI2
QI2
QI1
TRM TRM
TRM
QI5 QI3 QI5 QI3
QI5 QI3 QI3
QI3
Transport
Transport
Transport
Function ICF ICF ICF
ICF ICF
Function
Function
QoS Signalling
Transport Flow
Figure 5: TIPHON QoS Functional Entities
5.4 QoS reference points
The QoS reference points indicated in figure 5 are derived from the general reference points defined in TS 101 314 [2].
They are used for QoS only and are distinguished from their equivalent general reference points by the addition of the
letter Q. They are extensively explained in clause 8. In this clause a short description of each is given.
5.4.1 Reference point QC1
The QoS information flow between a QoSM and a User Equipment QoSM is captured in the QC1 reference point. The
information flow across this reference point communicates QoS related bearer information between an End User and
the End User's ITSP in the IP Telephony Application Plane.
5.4.2 Reference point QC2
Information flowing between two QoSMs in different service domains is captured in QC2. The information flow across
this reference point communicates QoS related bearer information between domains (ITSPs) in the IP Telephony
Application Plane.
5.4.3 Reference point QS4
Between a QoSM and a QoSPE. The information flow across this reference point communicates QoS policy
information relating to the establishment of a bearer with specified QoS levels.
5.4.4 Reference point QT2
Between a QoSM and its associated TRM(s). The information flow across this reference point communicates QoS
related transport flow information between a Service Domain and an associated Transport Domain. The information on
QT2 communicates the QoS related characteristics required of the transport flows that will carry the media flow, the
properties of the media flow, and addressing information related to the transport flows.
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14 ETSI TS 101 329-3 V2.1.2 (2002-01)
5.4.5 Reference point QT1
Between a User Equipment QoSM and an associated Transport Domain. The QoS information flow across this
reference point communicates the QoS related characteristics required of the local loop transport flows that will carry
the media flow, the properties of the media flow, and possibly addressing information related to the transport flows.
5.4.6 Reference point QI1
Between a TRM and a TRM in another Transport Domain. The QoS information flow across this reference point
communicates the QoS related characteristics required of the local loop transport flows that will carry the media flow,
the properties of the media flow, and possibly addressing information related to the transport flows.
5.4.7 Reference point QI2
Between two TRMs in different Transport Domains. The information flow across this reference point communicates the
QoS related characteristics required of the interconnect transport flows that will carry the media flow, the properties of
the media flow, and possibly addressing information related to the transport flows.
5.4.8 Reference point QI3
Between a TRM and an ICF. The information flow across this reference point controls the InterConnect Function and
enables it to perform its interworking and policing functions.
5.4.9 Reference point QI4
Between a TRM and its associated TPE. The information flow across this reference point is for further study.
5.4.10 Reference point QI5
Between a TRM and its associated TF. The information flow across this reference point is for further study.
6 Characterizing QoS
6.1 Service, application and transport level QoS parameters
Five end-to-end QOS classes applicable to TIPHON systems are defined in TS 101 329 2 [1]. These TIPHON QoS
classes are expressed in terms of the users perception of QoS and they form a suitable basis for QoS agreements
between the ITSPs and End-Users.
Within the IP Telephony application the subjective service level QoS Class is determined by a number of engineering
parameters which form part of the User Equipment, the network based equipment and the performance of the network
itself. Examples are the choice of codec, any forward error correction deployed, the packetization algorithm used, the
codec frame size, the algorithms used for handling packet delay variation at the receiver, the dejittering delay
introduced at the jitter buffers, error concealment techniques within the decoder and equipment processing delays. At
the application level, QoS agreements relating to the registration of User Equipment with ITSPs, must be specified in
terms of these application based parameters.
In practice most of these parameters will be determined by the User Equipment design, and control of end-to-end QoS
within the application will be reduced to the control of a number of basic network and equipment related parameters.
Specifically:
• maximum end-to-end delay;
• maximum end-to-end delay variation;
• maximum Packet loss.
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15 ETSI TS 101 329-3 V2.1.2 (2002-01)
End-to-end control of these parameters is necessary and sufficient to ensure guaranteed speech quality across a
particular speech path. Where multiple Transport Domains are involved in a call, the set of parameters must be
specified and controlled in each domain if quality is to be specified and controlled.
The QoS achievable at the application and service levels will depend ultimately on the performance of the underlying
transport networks supporting the IP telephony service. In the Transport Plane therefore the mean end to end delay,
delay variation and packet loss must be controlled.
Figure 6 describes the parameters that are relevant for each level.
TIPHO N Speech QoS Class
SERVICE
Codec, Fram es per Packet, Fram e Size, Jitter Buffer D elay,
FEC (R edundancy), O verall O ne-W ay D elay,
A PPLICA T IO N
Packet Loss
Packet Loss, M ean D elay, D elay V ariation
TRANSPORT
Figure 6: Service, application and transport QoS parameters
6.2 Interfacing to the Transport Plane
Although the QoS requirements arise from the IP telephony application, the parameters must be controlled in the
transport plane. The QoS requirements are speech quality related and are therefore independent of the mechanisms used
to control quality in the transport plane. Thus ATM, RSVP, DiffServ or MPLS or static network engineering could all
be used to control the required QoS parameters, or even a mixture of these mechanisms where multiple Transport
Domains are involved. The QoS requirements for a particular media flow must, however, be known to the transport
plane in order that the parameters can be controlled to the required levels.
For the purposes of interfacing to the transport plane a distinction is made between Transport QoS Parameters, which
specify the QoS levels to be delivered, and a traffic descriptor, which enables the transport network to optimally
manage the resources required.
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16 ETSI TS 101 329-3 V2.1.2 (2002-01)
6.2.1 Transport QoS parameters
The transport QoS parameters (maximum end-to-end delay, maximum end-to-end delay variation, maximum mean
packet loss) specify the QoS requirements of the transport flow carrying the bearer.
The format in which these parameters are specified may vary depending on individual circumstances. Different levels of
instantaneous control are possible and the way in which the parameters are specified will determine this. In general,
there are three possibilities:
1) specification of whether QoS is to be controlled on the bearer. Best effort speech communication implies that
QoS levels are not specified;
2) specification that any or all of the three parameters are to be controlled but that the values for the parameters are
specified elsewhere, e.g. by service level agreements;
3) specification of the absolute values for the three parameters.
These possibilities are provided by the general format of the transport QoS parameter group (see clause 9.2) which shall
be as follows:
Sub-Field 1: Maximum end-to-end delay
MaxDelayClass (enumeration) Possibility 2
MaxDelayValue (numeric) Possibility 3
Sub-Field 2: Maximum end-to-end delay variation
MaxDelayVariationClass (enumeration) Possibility 2
MaxDelayVariationValue (numeric) Possibility 3
Sub-Field 3: Maximum Mean Packet Loss
MaxMeanPacketLossClass (enumeration) Possibility 2
MaxMeanPacketLossValue (numeric) Possibility 3
where the above parameters are defined as follows:
MaxDelayClass:
This parameter shall specify a number representing an entry in a list of possible maximum delay values and based on a
priori agreement between business entities. The values of maximum delay to be included in this list are for further
study.
MaxDelayValue:
This parameter shall be used to specify the numerical value of the maximum delay.
MaxDelayVariationClass:
This parameter shall specify a number representing an entry in a list of possible maximum delay variation values and
based on a priori agreement between business entities. The values of maximum delay variation to be included in this list
are for further study.
MaxDelayVariationValue:
This parameter shall be used to specify the numerical value of the maximum delay variation.
MaxMeanPacketLossClass:
This parameter shall specify a number representing an entry in a list of possible maximum mean packet loss values and
based on a priori agreement between business entities. The values of maximum mean packet loss to be included in this
list are for further study.
ETSI
17 ETSI TS 101 329-3 V2.1.2 (2002-01)
MaxMeanPacketLossValue:
This parameter shall be used to specify the numerical value of the maximum mean packet loss.
For possibility 1, where no QoS control is required, the transport QoS Parameter Group shall be omitted from
information exchanges.
NOTE 1: The way in which the above variables are characterized is for further study.
NOTE 2: The use of a parameter to indicate the maximum permitted levels of packet loss in a burst of specified
duration is for further study.
6.2.2 Traffic descriptor
The traffic statistics of each bearer may be specified and signalled to
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