SIST-TS TS 102 024-9 V4.1.1:2004

• Abstract:

  The present document, TIPHON call completion performance classification, specifies the signalling aspects associated with the control of end-to-end QoS within and between TIPHON domains for Voice over IP. It defines call and media processing parameters, bounds on the values of these parameters and a possible classification system. The specified parameters apply to session and media flow set-up and close-down as well as to mid-session changes and include issues of signalling accuracy, signalling latency and signalling reliability.

• Status: Published
• Publication Date: 31-Mar-2004
• ICS: 33.020 - Telecommunications in general
• Technical Committee: SPN - Services and Protocols for Networks
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Apr-2004
• Due Date: 01-Apr-2004
• Completion Date: 01-Apr-2004
• Ref Project: ETSI TS 102 024-9 V4.1.1 (2003-01) - Telecommunications and Internet Protocol Harmonization Over Networks (TIPHON) Release 4; End-to-End Quality of Service in TIPHON Systems; Part 9: Call performance Classification (Voice)

SIST-TS TS 102 024-9 V4.1.1:2004 is the Slovenian adoption of ETSI TS 102 024-9 V4.1.1, published by the Slovenian Institute for Standardization (SIST). It specifies call performance classification for Telecommunications and Internet Protocol Harmonization Over Networks (TIPHON) Release 4, with a focus on end-to-end Quality of Service (QoS) signalling for Voice over IP. The document is aimed at people who need to define, measure or compare voice call completion behaviour across TIPHON domains.

What does SIST-TS TS 102 024-9 V4.1.1:2004 specify?

SIST-TS TS 102 024-9 V4.1.1:2004 specifies the signalling aspects used to control end-to-end QoS within and between TIPHON domains for Voice over IP. It defines call and media processing parameters, bounds for those parameters, and a possible classification system for call performance.

The scope covers:

• session and media flow set-up
• session and media flow close-down
• mid-session changes
• signalling accuracy, signalling latency and signalling reliability

A key practical point is that the document applies only to guaranteed QoS classes. It is not intended for best effort service.

Annex	What it covers
Annex A	Normative summary of the objectives for the call performance parameters
Annex B	Informative signalling reference connection, including call signalling elements and delay breakdowns

What are the key requirements of SIST-TS TS 102 024-9 V4.1.1:2004?

SIST-TS TS 102 024-9 V4.1.1:2004 focuses on how to classify and assess call completion performance in TIPHON voice systems. The main idea is to measure signalling outcomes and signalling delays at defined network reference points, then use those measurements against proposed objectives.

Signalling failure and error measures

Clause 4.1 defines the main failure-related parameters. These are the measures that tell a network operator whether calls are failing to set up, being misrouted, being released too early, or failing to clear properly.

• Call Setup Failure Probability (CSFP) measures call setup attempts that do not reach the expected alerting state. In practice, it is used to judge whether the network is successfully establishing calls.
• Call setup error probability (CSEP) covers network-caused wrong-number behaviour, where the call is established to the wrong destination. In practice, this matters because the called user is not the one intended by the caller.
• Signalling route unavailability applies only to Switched Circuit Network (SCN) portions of TIPHON systems. In practice, this is a route-set availability measure rather than an end-to-end QoS parameter.
• Call Premature Release Probability (CPRP) measures disconnects generated within a network portion before the expected call clearing sequence. In practice, it is used to detect unwanted releases caused by the network.
• Call Release Failure Probability (CRFP) measures failures to clear a call properly from one boundary to the other. In practice, this shows whether release signalling is being transferred correctly.
• Percentage of unsuccessful call attempts is the sum of CSFP and CSEP. In practice, it provides a broader view of failed call attempts than either parameter alone.

Call signalling delay measures

Clause 4.2 defines the delay measures used for call performance classification. These parameters describe how long signalling takes during setup and release, and they matter because delay affects user perception and resource availability.

• Call Setup Delay (CSD) is the time from enough address information being provided to the caller receiving confirmation that the called party is being alerted. In practice, this is the main setup delay users notice.
• Call Answer Signal Delay (CASD) is the time from the called terminal indicating readiness to the calling terminal receiving that indication. In practice, it relates to how quickly answer signalling is seen across the network.
• Call Release Delay (CRD) is the time from clearing being initiated to clearing confirmation being received. In practice, it affects how quickly resources are freed for the next call.

Annex A gathers the objectives for these parameters in one place. The document presents them as proposed or provisional objectives, so they are intended for consideration in performance classification rather than as final universal limits.

How the signalling model is structured

The document ties the measures to TIPHON reference points and metaprotocol events. That matters because the parameters are not abstract statistics - they are linked to observable setup, alerting and clearing events at originating and terminating sides.

Clause 4 also distinguishes between network-caused outcomes and user-blocking outcomes. That is important in practice because measurements for network performance should not be distorted by call rejections or terminal-side blocking outside the network portion being assessed.

What terms does SIST-TS TS 102 024-9 V4.1.1:2004 define?

• Unsuccessful call - a call attempt to a valid number where no busy tone, ringing tone or answer signal is recognized within 30 s after the network receives the address information needed to set up the call.
• Unsuccessful call ratio - the number of unsuccessful calls divided by the total number of call attempts in a given period.
• Call Setup Failure Probability (CSFP) - the ratio of call setup attempts that end in call setup failure to all call setup attempts in the population of interest.
• Call setup error probability (CSEP) - the ratio of call setup attempts that end in a network-caused call setup error to all call setup attempts.
• Call Premature Release Probability (CPRP) - the probability that, in any given second, a call experiences a premature disconnect generated within a defined network portion.
• Call Release Failure Probability (CRFP) - the ratio of call clearing failures to call clearing attempts in the population of interest.
• Call Setup Delay (CSD) - the time between sufficient address information being presented and confirmation that the called party is being alerted.
• Quality of Service (QoS) - the service quality concept used throughout the TIPHON series to describe measurable network and call performance.

Who uses SIST-TS TS 102 024-9 V4.1.1:2004?

SIST-TS TS 102 024-9 V4.1.1:2004 is used by TIPHON and VoIP engineers, network planners, signalling specialists, quality managers and service providers. It helps them define performance targets, compare measured call behaviour with the document’s objectives, and classify voice call performance across IP domains.

It is also relevant to buyers and technical evaluators who need to assess whether a TIPHON-based voice service is being designed or operated for end-to-end QoS rather than best effort delivery. In mixed networks, it is especially useful when a call crosses TIPHON and SCN portions or when roaming is involved.

Which standards are used with SIST-TS TS 102 024-9 V4.1.1:2004?

Document	What it contributes
ETSI TS 101 314	Abstract architecture and TIPHON reference points used to relate the signalling events to network boundaries
ETSI TS 101 882	Protocol framework and TIPHON metaprotocol messages used in the event definitions
ITU-T Recommendation Y.1530	Call processing performance context for voice service in hybrid IP networks
ITU-T Recommendation Y.1541	IP service performance objectives used for router delay figures
ITU-T Recommendation Q.766	Transit exchange transfer times used as a basis for call server delay estimates
ITU-T Recommendation Q.706	Signalling performance guidance, including route set availability
ITU-T Recommendation Q.709	Hypothetical signalling reference connection used for the delay model comparison
Directive 98/10/EC	European telephony and universal service context referenced in the delay discussion

The foreword also identifies the surrounding TIPHON series, which places this part in the wider end-to-end QoS set:

• TR 102 024-1 - General aspects of QoS
• TS 102 024-2 - Definition of Speech Quality of Service (QoS) Classes
• TS 102 024-3 - Signalling and Control of End-to-end QoS in a multi-media environment
• TS 102 024-4 - QoS Management
• TS 102 024-5 - QoS measurement methodologies
• TR 102 024-6 - Actual measurements of network and terminal characteristics and performance parameters
• TR 102 024-7 - Design Guide for elements of a TIPHON connection
• TS 102 024-10 - QoS Requirements for TIPHON Terminals

What does the SIST-TS TS 102 024-9 V4.1.1:2004 document contain?

SIST-TS TS 102 024-9 V4.1.1:2004 contains a parameter-based classification framework for voice call completion performance. Clause 4 defines the failure, error and delay parameters, while Annex A collects the proposed objectives in summary form.

Annex B provides an informative signalling reference connection model. It describes originating, transit and terminating domains, the TIPHON call signalling elements inside them, and the round-trip processing delays used for call setup analysis.

The document also includes figures and tables that support measurement and planning:

• Figure 1 defines the reference events for successful call setup
• Figure 2 shows an inter-domain signalling connection model
• Tables in Annex B break down processing delays for originating, transit and terminating domains
• Later tables combine TIPHON and SCN cases, including roaming scenarios, to show how signalling delay accumulates in different connection types

In practice, these contents support QoS planning, performance measurement and comparison of call setup and release behaviour across TIPHON voice networks.

SLOVENSKI STANDARD
01-april-2004
Harmonizacija telekomunikacij in internetnega protokola prek omrežij (TIPHON), 4.
izdaja - Kakovost storitve od konca do konca v sistemih TIPHON - 9. del:
Klasifikacija zmogljivosti klica (govor)
Telecommunications and Internet Protocol Harmonization Over Networks (TIPHON)
Release 4; End-to-End Quality of Service in TIPHON Systems; Part 9: Call performance
Classification (Voice)
Ta slovenski standard je istoveten z: TS 102 024-9 Version 4.1.1
ICS:
33.020 Telekomunikacije na splošno Telecommunications in
general
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 4;
End-to-end Quality of Service in TIPHON Systems;
Part 9: Call performance Classification (Voice)

2 ETSI TS 102 024-9 V4.1.1 (2003-01)

Reference
DTS/TIPHON-05016R4
Keywords
IP, performance, QoS, telephony, voice, VoIP
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© European Telecommunications Standards Institute 2003.
All rights reserved.
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DECT , PLUGTESTS and UMTS are Trade Marks of ETSI registered for the benefit of its Members.
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ETSI
3 ETSI TS 102 024-9 V4.1.1 (2003-01)
Contents
Intellectual Property Rights.4
Foreword.4
1 Scope.5
2 References.5
3 Definitions and abbreviations.6
3.1 Definitions.6
3.2 Abbreviations.6
4 Parameters.6
4.1 Signalling failure probability.6
4.1.1 Call Setup Failure Probability.6
4.1.2 Call setup error probability.8
4.1.3 Signalling route unavailability.8
4.1.4 Call Premature Release Probability .8
4.1.5 Call Release Failure Probability .8
4.1.6 Percentage of unsuccessful call attempts .9
4.2 Call signalling delays .9
4.2.1 Call setup delay.9
4.2.2 Call Answer Signal Delay.9
4.2.3 Call Release Delay.10
Annex A (normative): Summary of objectives .11
Annex B (informative): Signalling reference connection.12
B.1 General.12
B.2 TIPHON call signalling elements.12
B.3 Signal processing delays of TIPHON components .14
B.4 Total Signalling processing delay for call setup.16
B.4.1 Intra-domain TIPHON connection .17
B.4.2 Inter-domain TIPHON connections.17
B.4.3 Inter-domain connections involving TIPHON and Switched Circuit networks .18
B.4.4 Inter-domain connections involving roaming.19
History .20

ETSI
4 ETSI TS 102 024-9 V4.1.1 (2003-01)
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).
All published ETSI deliverables shall include information which directs the reader to the above source of information.
Foreword
This Technical Specification (TS) has been produced by ETSI Project Telecommunications and Internet Protocol
Harmonization Over Networks (TIPHON).
The present document is part 9 of a multi-part deliverable covering the End-to-end Quality of Service in TIPHON
Systems, as identified below:
TR 102 024-1: "General aspects of Quality of Service (QoS)";
TS 102 024-2: "Definition of Speech Quality of Service (QoS) Classes";
TS 102 024-3: "Signalling and Control of End-to-end Quality of Service (QoS) in a multi-media environment";
TS 102 024-4: "Quality of Service Management";
TS 102 024-5: "Quality of Service (QoS) measurement methodologies";
TR 102 024-6: "Actual measurements of network and terminal characteristics and Performance parameters in
TIPHON networks and their influence on voice quality";
TR 102 024-7: "Design Guide for elements of a TIPHON connection from an End-to-end speech transmission
performance point of view";
TS 102 024-9: "Call performance Classification (Voice)";
TS 102 024-10: "QoS Requirements for TIPHON Terminals".
ETSI
5 ETSI TS 102 024-9 V4.1.1 (2003-01)
1 Scope
The present document, "TIPHON call performance classification", specifies the signalling aspects associated with the
control of End-to-end QoS within and between TIPHON domains for Voice over IP. It defines call and media
processing parameters, bounds on the values of these parameters and a possible classification system. The specified
parameters apply to session and media flow set-up and close-down as well as to mid-session changes and include issues
of signalling accuracy, signalling latency and signalling reliability.
NOTE: The present document only applies to guaranteed QoS classes. Hence it is not applicable to the best effort
class.
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.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
[1] ETSI TS 101 314: "Telecommunications and Internet Protocol Harmonization Over Networks
(TIPHON) Release 3; Abstract Architecture and Reference Points Definition; Network
Architecture and Reference Points".
[2] ETSI TS 101 882: "Telecommunications and Internet Protocol Harmonization Over Networks
(TIPHON) Release 3; Protocol Framework Definition; General (meta-protocol)".
[3] ITU-T Recommendation Y.1530 (February 2002): "Call processing performance for voice service
in hybrid IP networks".
[4] ITU-T Recommendation Y.1541: "Network performance objectives for IP-based services".
[5] ITU-T Recommendation Q.766: "Performance objectives in the integrated services digital network
application".
[6] ITU-T Recommendation Q.706: "Message transfer part signalling performance".
[7] ITU-T Recommendation Q.709: "Hypothetical signalling reference connection".
[8] Directive 98/10/EC of the European Parliament and of the Council of 26 February 1998 on the
application of open network provision (ONP) to voice telephony and on universal service for
telecommunications in a competitive environment.
ETSI
6 ETSI TS 102 024-9 V4.1.1 (2003-01)
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
unsuccessful call: call attempt to a valid number, properly dialled following dial tone, where neither called party busy
tone, nor ringing tone, nor answer signal, is recognized on the access line of the calling user within 30 s from the instant
when the address information required for setting up a call is received by the network
unsuccessful call ratio: ratio of unsuccessful calls to the total number of call attempts in a specified time period
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
CASD Call Answer Signal Delay
CPDP Call Premature Disconnect Probability
CPRP Call Premature Release Probability
CRFP Call Release Failure Probability
CRD Call Release Delay
CSD Call Setup Delay
CSEP Call Setup Error Probability
CSFP Call Setup Failure Probability
DNS Domain Name Server
FFS For Further Study
ISDN Integrated Service Digital Network
QoS Quality of Service
SCN Switched Circuit Network
TE Terminal Equipment
4 Parameters
In this clause a set of parameters and values is proposed for consideration for the specification of the call completion
performance classification.
4.1 Signalling failure probability
4.1.1 Call Setup Failure Probability
The Call Setup Failure Probability (CSFP) is the ratio of total call setup attempts that result in call setup failure to the
total call setup attempts in a population of interest.

(a)
(b)
(c)
(d)
B     B
i j
Originating side Terminating side

Figure 1: Reference events occurring during successful call setup
ETSI
7 ETSI TS 102 024-9 V4.1.1 (2003-01)
With reference to figure 1, the CSFP is defined to occur on any call setup attempt in which either one of the following
outcomes is observed prior to expiration of timer T :
max
• both events (b) and (d) do not occur;
• events (b) and (c) occur, but event (d) does not.
Events (a) to (d) are observable events at specific reference points:
(a) illustrates setup at originating side;
(b) illustrates setup at terminating side;
(c) illustrates alerting at terminating side;
(d) illustrates alerting at originating side.
The reference points for TIPHON Release 4, corresponding to reference points B and B in figure 1 are specified
i j
in TS 101 314 [1]. The events occurring at those reference points correspond to specific TIPHON Metaprotocol
messages as defined in TS 101 882 [2].
In case of TIPHON Scenario 0, reference point B in figure 1 relates to reference point C1 at the originating side, while
i
B relates to reference point C1 at the terminating side. Reference point B relates to TIPHON reference point C3 in case
j j
of TIPHON scenario 1. B relates to TIPHON reference point C3 in case of TIPHON scenario 2.
i
The relationship between events (a) to (d) and the TIPHON Metaprotocol messages are as follows:
(a) corresponds to the entry of U_CallRequest at reference point C1 between the originating terminal device and the
SpoA for call control;
(b) corresponds to the exit of D_CallRequest at reference point C1 between the terminating SpoA and the
terminating terminal device;
(c) corresponds to the entry of U_CallAltert at reference point C1 between the terminating terminal device and the
terminating SpoA;
(d) corresponds to the exit of D_CallReport at reference point C1 between the originating SpoA and the
originating terminal device.
NOTE 1: The exact value of T is for further study.

max
NOTE 2: Call setup attempts that are cleared by the network portion as a result of incorrect performance or
non-performance on the part of an entity outside the network portion are excluded.
NOTE 3: A call setup attempt can fail as a result of user blocking. Such failures are excluded from network
performance measurement. Examples of user blocking include the following:
- the called user issues a message to reject the call setup attempt;
- the connect message reference event fails to occur at the originating MPT boundary due to the lack
of a connect message reference event at the terminating MPT boundary;
- the called user delays excessively in generating the connect message reference event during the call
period, with the result that a call is not established before the time-out;
- all channels at the called TE are in use.
-5
Objective: The Call Setup Failure Probability as defined above for a TIPHON network shall not exceed 3 x 10 .
NOTE 4: This is a provisional value. The actual target value is for further study.
ETSI
8 ETSI TS 102 024-9 V4.1.1 (2003-01)
4.1.2 Call setup error probability
Call setup error probability is the ratio of total call setup attempts that result in call setup error to the total call setup
attempts in a population of interest.
With reference to figure 1, a call setup error is defined to occur on any call setup attempt in which event (d) occurs, but
event (c) does not occur at an appropriate boundary prior to expiration of timer T.
Call setup error is essentially the case of a network-caused "wrong number". It occurs when the network responds to a
valid call request by erroneously establishing a call to a destination Terminal Equipment (TE) other than the one
designated in the call request, and does not correct the error prior to the user information transfer. It may be caused, for
example, by network operator administrative or maintenance actions.
Call setup error is distinguished from successful call setup by the fact that the intended called user is not contacted and
not committed to the session during the call setup attempt.
4.1.3 Signalling route unavailability
Important remark: The signalling route unavailability parameter is only applicable to the SCN network portions of
TIPHON systems. Hence it is not an End-to-end parameter.
The availability of a signalling route set is determined by the availability of the individual components of the signalling
network and by the structure of the signalling network. (i.e. the arrangements for redundancy and alternative routing in
the event of the unavailability of a component.)
ITU-T recommendation [6] Q.706, clause 1.1, recommends that the availability of a signalling route set should be not
less than 0,99998. This corresponds to a downtime of not more than ten minutes per year.
4.1.4 Call Premature Release Probability
The Call Premature Release Probability (CPRP) for a network portion is the probability, in any given second, that a call
experiences a premature disconnect generated within that portion.
A premature disconnect is defined as an occurrence of a Disconnect request or a Release message [2] exiting the
network portion at its originating or terminating network boundary,
• either in the absence of a previous corresponding Modify or Release message occurring at the other boundary
of the network;
• or when a premature disconnect stimulus occurs within the network boundaries and is transferred across its
originating or terminating boundaries.
The network portion boundaries are the same (B , B ) as shown in figure 1. They also correspond to the reference point
i j
between FE5 and FE6 for the originating side of a TIPHON network and the reference point between FE8 and FE9 for
the terminating side.
-5
Objective: The Call Premature Disconnect Probability (CPDP) as defined in this clause should not exceed 1,5 x 10 .
NOTE: This is a provisional value. The actual target value is for further study.
4.1.5 Call Release Failure Probability
The Call Release Failure Probability (CRFP) is the ratio of total call clearing failures to the total call clearing attempts
in a population
...