SIST ETS 300 326-3:1999

SLOVENSKI STANDARD
01-julij-1999
Elektromagnetna združljivost (EMC) in zadeve v zvezi z radijskim spektrom (ERM) -
Prizemni letalski telefonski sistem (TFTS) - 3. del: Govorne storitve, omrežni vidiki
ElectroMagnetic Compatibility and Radio Spectrum Matters (ERM); Terrestrial Flight
Telecommunications System (TFTS); Part 3: Speech services, network aspects
Ta slovenski standard je istoveten z: ETS 300 326-3 Edition 2
ICS:
33.060.01 Radijske komunikacije na Radiocommunications in
splošno general
33.100.01 Elektromagnetna združljivost Electromagnetic compatibility
na splošno in general
49.090 2SUHPDLQLQVWUXPHQWLY On-board equipment and
]UDþQLKLQYHVROMVNLKSORYLOLK instruments
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN ETS 300 326-3
TELECOMMUNICATION August 1998
STANDARD Second Edition
Source: ERM Reference: RE/ERM-RP05-005-3
ICS: 33.020
Key words: TFTS, network
Electromagnetic compatibility
and Radio spectrum Matters (ERM);
Terrestrial Flight Telecommunications System (TFTS);
Part 3: Speech services, network aspects
ETSI
European Telecommunications Standards Institute
ETSI Secretariat
Postal address: F-06921 Sophia Antipolis CEDEX - FRANCE
Office address: 650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE
Internet: secretariat@etsi.fr -
http://www.etsi.fr - http://www.etsi.org
Tel.: +33 4 92 94 42 00 - Fax: +33 4 93 65 47 16
Copyright Notification:
No part may be reproduced except as authorized by written permission. The copyright and the
foregoing restriction extend to reproduction in all media.
© European Telecommunications Standards Institute 1998. All rights reserved.

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ETS 300 326-3: August 1998
Whilst every care has been taken in the preparation and publication of this document, errors in content,
typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to
"ETSI Standards Making Support Dept." at the address shown on the title page.

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ETS 300 326-3: August 1998
Contents
Foreword .9
1 Scope . 11
2 Normative references . 11
3 Definitions and abbreviations. 12
3.1 Definitions. 12
3.2 Abbreviations. 12
4 TFTS network architecture. 14
4.1 General. 14
4.2 The functional entities of the TFTS. 14
4.2.1 The Ground Station System (GSS). 14
4.2.2 The GSC. 14
4.2.3 The GS . 14
4.2.4 The Interworking Function (IWF). 14
4.2.5 The AS. 15
4.3 Configuration of the TFTS network . 15
4.3.1 General. 15
4.3.2 Description of the TFTS configuration . 16
4.4 TFTS network interfaces . 17
4.4.1 General. 17
4.4.2 Interface between the GSC and GSs (Ub) . 17
4.4.3 Interface between AS and GS system (Ua). 17
4.5 Interfaces with the fixed networks . 17
4.5.1 Interface between the GSC and the fixed networks. 17
4.5.2 Scope of TFTS specification . 17
4.6 Interfaces between AC, OMC and NMC, and the fixed networks . 18
4.7 Network connection types. 18
4.7.1 Introduction. 18
4.7.2 General considerations. 18
4.7.2.1 Relationship between lower layer capabilities and radio
traffic channels. 18
4.7.2.2 Lower layer capabilities. 18
4.7.3 Framework for the description of connection types . 19
4.7.3.1 Introduction. 19
4.7.3.2 Purpose of TFTS connection types . 19
4.7.3.3 Functions associated with TFTS connection. 20
4.7.3.4 Applications of TFTS connection types. 20
4.7.4 TFTS connection types. 21
4.7.4.1 Description of TFTS connection types . 21
4.7.4.2 TFTS connection elements . 21
4.7.4.3 Rules of association for the attribute values of connection
elements and connection types. 21
4.7.4.3.1 Information transfer mode. 21
4.7.4.3.2 Information transfer rate (kbits/s) . 21
4.7.4.3.3 Information transfer susceptance. 22
4.7.4.3.4 Establishment of connection. 22
4.7.4.3.5 Symmetry. 22
4.7.4.3.6 Connection configuration. 22
4.7.4.3.7 Structure . 22
4.7.4.3.8 Channels . 22
4.7.4.3.9 Connection control protocol. 23

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ETS 300 326-3: August 1998
4.7.4.3.10 Information transfer coding/protocol.23
4.7.4.3.11 Further attributes and attribute values .24
4.7.4.4 Limited set of TFTS connection types.25
4.7.5 Relationship between bearer and connection types .25
4.7.6 List of definitions of TFTS connection type attributes and their values.26
4.7.6.1 Attribute definition and their values .26
4.7.6.2 Definition of values.27
5 Fixed network interworking.27
5.1 Interworking requirements.27
5.1.1 Interworking definition.27
5.1.2 Interworking between networks.27
5.1.2.1 Network interworking .27
5.1.2.2 Service interworking.28
5.2 Network interworking traffic part.28
5.2.1 General .28
5.2.2 Definitions.28
5.2.3 Traffic part introduction.29
5.2.4 Network characteristics.29
5.2.4.1 Key characteristics of networks concerned.29
5.2.4.2 Characteristics of PSTNs .29
5.2.4.3 Interworking classification.30
5.2.4.3.1 Network interworking.30
5.2.4.3.2 Signalling interworking.30
5.2.4.3.3 Numbering .30
5.2.5 Interworking to the PSTN/ISDN .30
5.2.5.1 Interworking indications to TFTS terminals.30
5.2.5.2 Transmission aspects.31
5.3 Interworking to the ISDN.31
6 Call handling and handover procedures .31
6.1 General.31
6.2 Handover criteria and resource allocation management .31
6.2.1 General .31
6.2.2 General handover decisions .31
6.2.2.1 AS need for handover .31
6.2.2.2 GS need for handover.32
6.2.2.3 Handover decision point priority.32
6.2.3 Handover strategy to be applied at AS.32
6.2.4 Handover strategy to be applied at AS for cell boundary selection.32
6.2.5 Alternative handover strategy to be applied at AS for cell boundary
selection.33
6.2.6 Conflict in signalling requirements.33
6.2.7 Resource management strategy to be applied at the GS.33
6.2.7.1 General requirements on GS resource management.33
6.2.8 Handover failure actions due to lack of resources.34
6.2.8.1 Handover failure action at the GS side due to lack of
resources.34
6.2.8.2 AS action on handover failure due to resource shortage.35
6.2.8.2.1 Handover initiated due to poor link
quality.35
6.2.8.2.2 Handover initiated due to cell boundary 35
6.2.8.2.3 Handover initiated due to physical
condition.35
6.2.9 General handover and cell selection issues.35
6.3 Call handling and handover management procedures .35
6.3.1 General .35
6.3.2 Call handling procedures.36
6.3.2.1 General aspects.36
6.3.2.2 Functional aspects for call handling .36

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ETS 300 326-3: August 1998
6.3.2.2.1 AS functional entities . 37
6.3.2.2.2 GS functional entities. 38
6.3.2.2.3 GSC functional entities. 38
6.3.2.3 Call handling phases . 39
6.3.2.3.1 Resource set-up phase. 39
6.3.2.3.2 Call set-up phase . 40
6.3.2.3.3 Conversation phase. 40
6.3.2.3.4 Call release phase. 40
6.3.2.3.5 Resource Release phase. 41
6.3.3 Handover procedures . 41
6.3.3.1 Handover decision . 41
6.3.3.1.1 Reasons for handover. 41
6.3.3.1.2 Strategy for handover. 42
6.3.3.2 Handover management . 42
6.3.3.2.1 Resource management. 42
6.3.3.2.2 Handover phase organization. 42
6.3.3.2.3 Failure procedures . 43
6.3.3.3 Functional composition of TFTS stations. 43
6.3.3.3.1 AS functional composition for handover 45
6.3.3.3.2 GS functional composition for
handover . 45
6.3.3.3.3 GSC functional composition for
handover . 48
6.3.3.4 Handover general description. 56
6.3.3.4.1 Handover between channels of the GS. 56
6.3.3.4.2 Handover between GSs of different
GSC. 61
6.4 Network interworking handover part. 64
6.4.1 General. 64
6.4.2 TFTS/PSPDN interworking requirements. 64
6.4.3 TFTS/ISDN interworking requirements . 65
6.4.4 TFTS/PSTN interworking requirements . 65
6.5 Handover part specification. 65
6.5.1 Introduction. 65
6.5.2 Interface presentation. 65
6.5.2.1 General . 65
6.5.2.2 Objectives. 67
6.5.2.3 General characteristics . 67
6.5.2.3.1 Technique of description . 67
6.5.2.3.2 Primitives. 67
6.5.2.3.3 Peer-to-peer communication . 67
6.5.3 Structure of signalling functions. 68
6.5.3.1 Basic groups of functions . 68
6.5.3.2 Protocol architecture. 68
6.5.4 Services provided by handover signalling layer. 69
6.5.4.1 CC services . 69
6.5.4.2 MRM services . 69
6.5.4.3 HRM services. 70
6.5.5 Services assumed from network layer. 70
6.5.5.1 General . 70
6.5.5.2 Service primitives. 70
6.5.6 Inter-layer service interfaces. 71
6.5.6.1 Services provided by HRM entity . 71
6.5.6.1.1 General. 71
6.5.6.1.2 Service primitives . 71
6.5.7 Functions to be provided by the handover layer entities. 73
6.5.7.1 Functions provided by the HRM entity. 73
6.5.7.2 Functions provided by the CCM entity . 73
6.5.7.3 Function provided by the RF. 73
6.5.7.4 Functions provided by the Distribution Function (DF). 73

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ETS 300 326-3: August 1998
6.5.7.5 Functions provided by the MRM entity.73
6.5.8 Elementary procedures for HRM.74
6.5.8.1 General.74
6.5.8.2 Inter GSC Connection .74
6.5.8.3 HRM.74
6.5.8.4 Handover processing.74
6.5.8.4.1 Outgoing handover procedure.74
6.5.8.4.2 Incoming handover procedure.75
6.5.8.5 Handover information transmission .76
6.5.8.6 TCH release.76
6.5.8.7 Data message transmission.76
6.5.9 Message functional definition and contents .77
6.5.9.1 Messages for HRM.77
6.5.9.2 Handover resource messages.77
6.5.9.2.1 TCH release.78
6.5.9.2.2 Release Confirm.78
6.5.9.3 Handover messages between GSCs.78
6.5.9.3.1 HO-Request.78
6.5.9.3.2 HO-Confirm.79
6.5.9.3.3 HO-COMMAND.79
6.5.9.3.4 HO-Complete.80
6.5.9.3.5 HO-Reject.80
6.5.9.3.6 HO-Failure.80
6.5.9.3.7 HO-Information.81
6.5.9.4 Miscellaneous messages.81
6.5.9.4.1 Connect.81
6.5.9.4.2 Disconnect.81
6.5.9.4.3 CCM message transfer.82
6.5.9.4.4 MRM message transfer .82
6.5.9.5 Messages for MRM .82
6.5.10 Message format and information element coding.82
6.5.10.1 Overview.82
6.5.10.2 Message type .83
6.5.10.3 Other information elements.84
6.5.10.3.1 HRM information elements .88
6.5.10.3.2 Handover procedure reference .88
6.5.10.3.3 GS Identifier .89
6.5.10.3.4 ATEI.89
6.5.10.3.5 Handover resource identifier.90
6.5.10.3.6 Handover resource description .90
6.5.10.3.7 Handover call numbers information
element .91
6.5.10.3.8 Handover resource identifier list.92
6.5.10.3.9 Handover characteristics.93
6.5.10.3.10 Allocated frequency.93
6.5.10.3.11 Allocated slots.94
6.5.10.3.12 HRM Cause .94
6.5.10.3.13 CCM data message.95
6.5.10.3.14 MRM data message .96
6.5.10.3.15 Call Data Description.96
6.5.10.3.16 Service Provider Ident.98
6.5.11 Handling of error conditions.98
6.5.11.1 Transport disconnect.98
6.5.11.2 Release resource already released.98
6.5.11.3 Unknown handover resource identifier.98
6.5.11.4 Unknown handover reference.98
6.5.12 Handover diagrams.99
6.5.12.1 Handover scenario diagrams.99
6.5.12.1.1 Normal case.99
6.5.12.1.2 Reject by Old-GSC.99

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ETS 300 326-3: August 1998
6.5.12.1.3 Reject by New-GSC . 100
6.5.12.1.4 Reject by the New-GS. 100
6.5.12.1.5 Reject by the New-GSC after HO-
CONFIRM . 100
6.5.12.1.6 Failure by the AS. 101
6.5.12.2 State diagram and System Description Language (SDL)
of HRM. 101
6.6 GSC - GSC isolation and restoration . 111
6.6.1 General. 111
6.6.2 Isolation. 111
6.6.3 Handover resource states. 111
6.6.3.1 Handover resource dynamic states . 111
6.6.3.2 Handover resource usage states. 112
6.6.4 Restart procedure. 112
6.6.4.1 General restart procedure. 112
6.6.4.2 Handover resource dynamic state diagram . 113
6.6.5 Handover Resource Maintenance . 113
6.6.5.1 Handover resource usage state modification procedure . 113
6.6.5.2 Handover resource usage state diagram . 114
6.6.6 Messages functional definition and contents . 114
6.6.6.1 Restart message. 114
6.6.6.2 Restart acknowledge message. 115
6.6.6.3 Service message. 115
6.6.6.4 Service acknowledge message. 115
6.6.7 Message format and information element coding . 116
6.6.7.1 General message format. 116
6.6.7.2 Message type . 116
6.6.7.3 Other information elements. 117
6.6.7.4 MRM transaction reference. 117
6.6.7.5 Handover resource identity and state . 117
History. 119

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ETS 300 326-3: August 1998
Foreword
This second edition European Telecommunication Standard (ETS) has been produced by the
Electromagnetic compatibility and Radio spectrum Matters (ERM) Technical Committee of the European
Telecommunications Standards Institute (ETSI).
This ETS has been split into three parts as follows:
Part 1: "Speech services, facilities and requirements";
Part 2: "Speech services, radio interface";
Part 3: "Speech services, network aspects".
Transposition dates
Date of adoption of this ETS: 24 July 1998
Date of latest announcement of this ETS (doa): 31 October 1998
Date of latest publication of new National Standard
or endorsement of this ETS (dop/e): 30 April 1999
Date of withdrawal of any conflicting National Standard (dow): 30 April 1999

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ETS 300 326-3: August 1998
1 Scope
This European Telecommunication Standard (ETS) covers the specification of equipment for provision of a
terrestrial Aeronautical Public Correspondence (APC) service working in the frequency spectrum bands
allocated at World Administrative Radio Conference (WARC) 92 (1 670 to 1 675 MHz and 1 800 to
1 805 MHz). The ETS fully specifies aspects of the radio interface and Terrestrial Flight
Telecommunication System (TFTS) Ground Network (GN) required to maintain interoperability of
equipment. Within Europe European Radiocommunications Committee (ERC) Decision
ERC/DEC (92)01 [13] is applicable to TFTS frequency spectrum.
The general architecture of the TFTS is considered in ETS 300 326-1 [1]. This part expands on that
explanation to consider aspects of fixed network interworking. This part does not specify any specific
signalling system for that purpose. It only specifies the functionality required for correct operation of the
system.
Call handling and decision processes are specified. These should be used in conjunction with
ETS 300 326-2 [2]. These explanations include the decision processes for the handover function.
Signalling requirement between Ground Switching Centres (GSCs) are specified for supporting inter-GSC
handovers.
The TFTS Aircraft Station (AS) was specified by the European Airlines Electronics Committee (EAEC) and
has subsequently been adopted as (ARINC) Characteristic 752 [14] by the Airlines Electrical Engineering
Committee (AEEC). ARINC Characteristic 752 [14] makes reference to this ETS for specification of certain
radio and telecommunication matters to avoid ambiguity. The TFTS AS is one of a set of facilities within an
overall architecture being defined for aircraft on board telecommunications by the AEEC.
An Interim European Telecommunications Standard (I-ETS) is being produced which covers aspects of
conformance testing for TFTS aircraft mobile stations. The specification of data application and facsimile
will be the subject of a further (I-)ETS.
2 Normative references
This ETS incorporates by dated or undated reference, provisions from other publications. These normative
references are cited at the appropriate places in the text and the publications listed hereafter. For dated
references, subsequent amendments to or revisions of any of these publications apply to this ETS only
when incorporated in it by amendment or revision. For undated references the latest edition of the
publication applies.
[1] ETS 300 326-1: "Electromagnetic compatibility and Radio spectrum Matters
(ERM); Terrestrial Flight Telecommunication System (TFTS); Part 1: Speech
services, facilities and requirements".
[2] ETS 300 326-2: "Electromagnetic compatibility and Radio spectrum Matters
(ERM); Terrestrial Flight Telecommunication System (TFTS); Part 2: Speech
services, radio interface".
[3] CCITT I-Series of Recommendations (I.500 - I.605).
[4] CCITT Recommendation E.164 (1997): "The international public
telecommunication numbering plan".
[5] CCITT Recommendation E.163: "Numbering plan for the international telephone
service".
[6] CCITT Recommendation I.112: "Vocabulary of terms for ISDNs".
[7] CCITT Recommendation I.310: "ISDN-Network functional principles".

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ETS 300 326-3: August 1998
[8] CCITT Recommendation X.25: "Interface between Data Terminal Equipment
(DTE) and Data Circuit-terminating Equipment (DCE) for terminals operating in
the packet mode and connected to public data networks by dedicated circuit".
[9] CCITT Recommendation X.1: "International user classes of service in, and
categories of access to, public data networks and Integrated Services Digital
Networks (ISDNs)".
[10] CCITT Recommendation X.121: "International numbering plan for public data
networks".
[11] CCITT Recommendation X.200 (1988): "Reference model of open system
interconnection for CCITT applications".
[12] CCITT Recommendation X.210 (11/93): "Open systems interconnection layer
service definition".
[13] ERC Decision ERC/DEC (92)01: "Decision on the frequency bands to be
designated for the coordinated introduction of the Terrestrial Flight
Telecommunications System (TFTS)".
[14] ARINC Characteristic 752: "Terrestrial Flight Telephone System (TFTS) Airborne
Radio Subsystem".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of this ETS, the following definitions apply:
(digital) connection: A concatenation of (digital) transmission channels or (digital) telecommunication
circuits, switching and other functional units set up to provide for the transfer of (digital) signals between
two or more points in a telecommunication network to support a single communication.
TFTS connection: A connection that is established through TFTS between specified TFTS reference
points.
TFTS connection type: A description of a set of TFTS connections which have the same characteristics.
3.2 Abbreviations
For the purposes of this ETS, the following abbreviations apply:
AC Administrative Centre
AEEC Airlines Electrical Engineering Committee
AEN Aircraft Equipment Number
APC Aeronautical Public Correspondence
ARINC Aeronautical Radio INCorporated
AS Aircraft Station
ASI Aircraft Station Identity
AT Avionics Termination
ATE Airborne Telecommunications Equipment
ATEI Aircraft Termination Equipment Identifier
BCCH Broadcast Control Channel
CC Call Control
CCd Country Code
CCM Call Control Management
CCITT Consultative Committee on International Telegraphy and Telephony
CEI Content of Information Element
DCCH Dedicated Control Channel

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ETS 300 326-3: August 1998
DDI Direct Dial In
DTE Data Terminal Equipment
DTMF Dual Tone Multi-Frequency
EAEC European Airlines Electronics Committee
FACCH Fast Associated Control Channel
GCC Ground switching Centre Code
GCT Ground station Cell Type
GN Ground Network
GS Ground Station
GSC Ground Switching Centre
GSIC Ground Station Identity Code
GSN Ground station Serial Number
GSS Ground Station System
HRM Handover Resource Management
HO Handover
IEI Information Element Identifier
INTGS Intermediate Ground Station
ISDN Integrated Services Digital Network
IWF InterWorking Function
LI Length Indicator
MF Mandatory Fixed (information elements)
MR Maintenance Resource
MRM Maintenance Resource Management
MV Mandatory Variable (information elements)
NMC Network Management Centre
OF Optional Fixed (information elements)
OM Operations and Maintenance
OMC Operations and Maintenance Centre
OSI Open Systems Interconnection
OV Optional Variable
PAD Packet Assembler Disassembler
PDU Protocol Data Unit
PSPDN Packet Switched Public Data Network
PSTN Public Switched Telephone Network
RF Relay Function
RR Radio Resource
RRM Radio Resource Management
SABM Set Asynchronous Balanced Mode
SACCH Slow Associated Control Channel
SAP Service Access Point
SDL System Description Language
TCH Traffic Channel
TDMA Time Division Multiple Access
TE Terminal Equipment
TFTS Terrestrial Flight Telephone System
TI Transaction Identifier
TRM Terrestrial Resource Management
UA Unnumbered Acknowledgement
WARC 92 World Administrative Radio Conference 1992
WOW Weight On Wheels
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ETS 300 326-3: August 1998
4 TFTS network architecture
4.1 General
The basic network architecture of the TFTS is described in ETS 300 326-1 [1]. The following subclauses
elaborate some of the functions performed by the entities of the TFTS.
4.2 The functional entities of the TFTS
To provide the TFTS service it is necessary to define some specific functions. These functions may be
implemented in, or gathered into, different equipments. In any case, exchanges of data occur between
these functions.
4.2.1 The Ground Station System (GSS)
The radio equipment of a GSS (transceivers, controllers, etc.) may sustain one or more cells. A GSS may
consist of one or more Ground Stations (GS). Where a GS-GSC interface is implemented, it shall consist
of one GSC and several GSs.
There are three different types of GSs as described in ETS 300 326-1 [1]:
- airport stations;
- intermediate stations; and
- en-route stations.
4.2.2 The GSC
The GSC constitutes the interface between the radio system and the fixed networks. It performs all the
switching functions for ASs located in a geographical area designated as the GSC area. The main
difference between a GSC and an exchange in a fixed network is that the GSC takes into account the
impact of the allocation of radio resources and the mobile nature of the subscribers and performs in
addition, at least the following procedures:
- procedures for call-set up;
- procedures required for the aircraft access validity check;
- procedures required for handover;
- procedures for Operations and Maintenance (OM).
4.2.3 The GS
A GS is a network component which comprises the transceiver equipment needed to establish the radio
link between the GN and ASs. The GS services one cell and is controlled by a GSC.
4.2.4 The Interworking Function (IWF)
The IWF is an entity associated with the GSC. The IWF provides the functionality necessary to allow
interworking between the TFTS network and the fixed networks (i.e. Public Switched Telephone Network
(PSTN), Integrated Services Digital Network (ISDN) and Packet Switched Public Data Network (PSPDN)).
The IWF converts the protocols used in the TFTS network to those used in the appropriate fixed network.
The IWF may have no functionality where the service implementation in the TFTS network is directly
compatible with that at the fixed network. The interworking requirements are described in clause 5.

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ETS 300 326-3: August 1998
4.2.5 The AS
A description of an AS is given in ETS 300 326-1 [1], subclause 4.3.1.
4.3 Configuration of the TFTS network
4.3.1 General
The basic configuration of the TFTS network and the interconnection to the PSTN, ISDN and PSPDN is
presented in figure 1. This configuration presents all possible signalling interfaces which can be found in the
TFTS network. The specific implementation in each country may differ; particular functions may be
gathered in the same equipment and then these interfaces may become internal interfaces.
In any case the implementation of particular TFTS network components has no impact on the TFTS
network.
In the basic configuration presented in figure 1, all the functions are considered implemented in different
equipments. Therefore, all the interfaces within the TFTS network are external. From this configuration, all
the possible TFTS network organizations may be deduced. In the case when some functions are contained
in the same equipment, the relevant interfaces become internal to that equipment.

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ETS 300 326-3: August 1998
Figure 1: TFTS Interfaces
4.3.2 Description of the TFTS configuration
There may be none, one or more GSC interfaces from the TFTS network to the PSTN, ISDN and PSPDN
in any country. Among switching functions, the GSC performs the control of the user access to the TFTS
network. Handover functions may be performed between GSCs via the fixed networks or a dedicated
handover network. Handover functions between GSs of the same GSS or between radio channels of a GS
are performed within a GSS without the PSTN, ISDN or PSPDN being involved.
There is an Administrative Centre (AC) which may perform the following functions:
- data collection to support billing; and
- other service oriented central tasks.

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ETS 300 326-3: August 1998
There is a Network Management Centre (NMC) which supports management tasks that need to be
globally co-ordinated for the system.
The system and equipment Operations and Maintenance (OM) within one or several GSS are performed
by an Operation and Maintenance Centre (OMC).
The AC, NMC and OMC communicate to the GSSs via the fixed networks.
4.4 TFTS network interfaces
4.4.1 General
The implementation of the TFTS service implies the exchange of data between the equipments involved in
the service.
4.4.2 Interface between the GSC and GSs (Ub)
The interface between the GSC and its GSs is not specified in this ETS.
4.4.3 Interface between AS and GS system (Ua)
The interface between the AS and the GS is described in ETS 300 326-2 [2].
4.5 Interfaces with the fixed networks
4.5.1 Interface between the GSC and the fixed networks
In order to perform the required functions of the TFTS network there are five different types of interfaces
between the GSC and the fixed network:
- the user traffic interface (1a);
- the handover interface (1b);
- the AC interface (1c1);
- the NMC interface (1c2);
- the Operations and Maintenance (OM) interface (1c3).
The interfaces with fixed networks, including dedicated networks, are described in this part.
The GSC 1a and 1b interfaces interface to the fixed network(s) without causing any changes to the fixed
networks(s).
The GSC 1b interfaces (i.e. handover) is used to support handover between different GSSs within the
TFTS. This interface is described in clause 6.
The GSC 1c1 interface is used for communication with the Administration Centre.
The GSC 1c2 interface may be used to communicate directly with the NMC.
The GSC 1c3 interface is used to communicate with the OMC.
4.5.2 Scope of TFTS specification
With the exception of the data aspects and interface requirements defined in ETS 300 326-1 [1] and
clause 5, the specification of interfaces 1c1, 1c2 and 1c3 is outside the scope of this ETS.

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ETS 300 326-3: August 1998
4.6 Interfaces between AC, OMC and NMC, and the fixed networks
The specification of interfaces 2c1 and 2c2 is outside the scope of this ETS.
4.7 Network connection types
4.7.1 Introduction
The TFTS may be described by a limited set of access interfaces and a limited set of TFTS connection
types to support the telecommunication services described in ETS 300 326-1 [1]. This subclause identifies
and defines these connection types in so far as they relate to the particular network capabilities.
The basic lower layer capabilities shall be represented by a set of connection types. The definition of a set
of connection types shall provide the necessary information to identify network capabilities of TFTS. In
addition to describing network capabilities the identification of connection types shall facilitate the
specification of network-to-network interfaces. It may also assist in the allocation of network performance
parameters.
4.7.2 General considerations
Low layer capabilities are defined in ETS 300 326-1 [1], clause 5. All Bearer Services shall be provided
using low layer capabilities in the connection mode.
4.7.2.1 Relationship between lower layer capabilities and radio traffic channels
The realization of lower layer capabilities for the provision of telecommunication services shall make use of
a physical medium consisting of Traffic Channel(s) (TCH). For each connection at least one TCH shall be
used, and no multiplexing of low data rate connections on one TCH is allowed.
4.7.2.2 Lower layer capabilities
One class of lower layer capabilities is identified and is a transparent class which is characterized by
constant throughput, constant transit delay and variable error rate, which is applicable to speech services.
The definition described above provides the basis for the definition of a limited set of connection types to
be implemented by a TFTS.
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4.7.3 Framework for the description of connection types
4.7.3.1 Introduction
TFTS shall provide a set of network capabilities which enable telecommunication services to be offered to
a user.
A TFTS connection shall be a connection established between TFTS reference points.
NOTE: A TFTS connection type is a way of referring to, and describing, a TFTS connection.
Therefore, each TFTS connection may be characterized as belonging to a particular
connection type.
Figure 2 illustrates the concepts.
Figure 2: Framework for the description of TFTS connections
4.7.3.2 Purpose of TFTS connection types
The definition of a set of TFTS connection types shall provide the necessary input to identify the network
capabilities of a TFTS. Other key requirements of TFTS are contained in ETS 300 3261 [1]. In addition to
describing network capabilities of TFTS, the identification of connection types shall facilitate the
specification of network-to-network interfaces. It may also assist in the allocation of network performance
parameters.
NOTE: The user specifies only the telecommunication service required, whilst the TFTS
allocates the resources to set up a connection of the specific type as necessary to
support the requested service. It is further noted that, for certain service offerings,
additional network functions, e.g. additional lower layer functions and/or higher layer
functions, may be required (see figure 3).
Figure 3: The role of network capabilities in supporting service offering

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4.7.3.3 Functions associated with TFTS connection
Any TFTS connection shall involve an association of functions to support telecommunication services as
shown in figure 4. Three sets of functions are required:
- connection means, including transmission and switching;
- control functions and protocols, including signalling, flow/congestion control and routing functions;
- OM functions, including network management and maintenance functions.
Figure 4: Functional description
4.7.3.4 Applications of TFTS connection types
The situation to which TFTS connection types shall apply is given in figure 5.
NOTE: The term "Network" implies any fixed transit network as described in clause 6.
Figure 5: TFTS network connection

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4.7.4 TFTS connection types
4.7.4.1 Description of TFTS connection types
The characterization of TFTS connection types shall be implemented using a set of attributes. A TFTS
connection type attribute shall be specific characteristic of a TFTS connection type whose values shall
distinguish it from another TFTS connection type. Particular values shall be assigned to each attribute.
The definitions of the attributes and the attribute values are contained in subclause 4.7.6.
A TFTS connection type shall be partitioned into connection elements. This partitioning shall be based on
the two most critical transitions of a connection as follows:
- the change of signalling system; and
- the type of transmission system.
Subclause 4.7.4.3 describes the relationship between the attribute values of connectio
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