Digital cellular telecommunications system (Phase 2) (GSM); General requirements on interworking between the Public Land Mobile Network (PLMN) and the Integrated Services Digital Network (ISDN) or Public Switched Telephone Network (PSTN) (GSM 09.07)

The purpose of this European Telecommunication Standard (ETS) is to id entify the Mobile-services Switching Centre (MSC)/Interworking Functio ns (IWFs) and requirements to support interworking between: i)   PLMN and PSTN ii)   PLMN and ISDN  It is not possible to treat ISDN and PSTN as one type of network, even when both ISDN and PSTN subscribers are served by the same exchange b ecause of the limitations of the PSTN subscribers access i.e. analogue connection without D-channel signalling. Within this ETS, the requirements for voice and non-voice (data) calls are considered separately.

Digitalni celični telekomunikacijski sistem (faza 2) – Splošne zahteve za medsebojno delovanje med javnim kopenskim mobilnim omrežjem (PLMN) in digitalnim omrežjem z integriranimi storitvami (ISDN) ali javnim komutiranim telefonskim omrežjem (PSTN) (GSM 09.07)

General Information

Status
Published
Publication Date
30-Nov-2003
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
01-Dec-2003
Due Date
01-Dec-2003
Completion Date
01-Dec-2003

Buy Standard

Standard
SIST ETS 300 604 E6:2003
English language
60 pages
sale 10% off
Preview
sale 10% off
Preview

e-Library read for
1 day

Standards Content (sample)

SLOVENSKI STANDARD
SIST ETS 300 604 E6:2003
01-december-2003
'LJLWDOQLFHOLþQLWHOHNRPXQLNDFLMVNLVLVWHP ID]D ±6SORãQH]DKWHYH]D
PHGVHERMQRGHORYDQMHPHGMDYQLPNRSHQVNLPPRELOQLPRPUHåMHP 3/01 LQ
GLJLWDOQLPRPUHåMHP]LQWHJULUDQLPLVWRULWYDPL ,6'1 DOLMDYQLPNRPXWLUDQLP
WHOHIRQVNLPRPUHåMHP 3671  *60

Digital cellular telecommunications system (Phase 2) (GSM); General requirements on

interworking between the Public Land Mobile Network (PLMN) and the Integrated
Services Digital Network (ISDN) or Public Switched Telephone Network (PSTN) (GSM
09.07)
Ta slovenski standard je istoveten z: ETS 300 604 Edition 6
ICS:
33.040.35 Telefonska omrežja Telephone networks
33.070.50 Globalni sistem za mobilno Global System for Mobile
telekomunikacijo (GSM) Communication (GSM)
33.080 Digitalno omrežje z Integrated Services Digital
integriranimi storitvami Network (ISDN)
(ISDN)
SIST ETS 300 604 E6:2003 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST ETS 300 604 E6:2003
---------------------- Page: 2 ----------------------
SIST ETS 300 604 E6:2003
EUROPEAN ETS 300 604
TELECOMMUNICATION May 1997
STANDARD Sixth Edition
Source: ETSI TC-SMG Reference: RE/SMG-040907PR5
ICS: 33.020

Key words: Digital cellular telecommunications system, Global System for Mobile communications (GSM)

GLOBAL SYSTEM FOR
MOBILE COMMUNICATIONS
Digital cellular telecommunications system (Phase 2);
General requirements on interworking between the Public Land
Mobile Network (PLMN) and the Integrated Services Digital
Network (ISDN) or Public Switched Telephone Network (PSTN)
(GSM 09.07)
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
X.400: c=fr, a=atlas, p=etsi, s=secretariat - Internet: secretariat@etsi.fr
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 1997. All rights reserved.
---------------------- Page: 3 ----------------------
SIST ETS 300 604 E6:2003
Page 2
ETS 300 604 (GSM 09.07 version 4.12.1): May 1997

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 Editing and Committee Support Dept." at the address shown on the title page.

---------------------- Page: 4 ----------------------
SIST ETS 300 604 E6:2003
Page 3
ETS 300 604 (GSM 09.07 version 4.12.1): May 1997
Contents

Foreword .......................................................................................................................................................7

1 Scope ..................................................................................................................................................9

2 Normative references..........................................................................................................................9

3 Definitions and abbreviations ............................................................................................................12

4 Introduction........................................................................................................................................13

5 Not used............................................................................................................................................14

6 Network Characteristics ....................................................................................................................14

6.1 Key Characteristics of Networks Concerned .....................................................................14

6.1.1 Characteristics of PLMNs..............................................................................14

6.1.2 Characteristics of PSTNs ..............................................................................14

6.1.3 Characteristics of ISDN.................................................................................15

7 Interworking classifications ...............................................................................................................15

7.1 Service interworking...........................................................................................................15

7.2 Network interworking .........................................................................................................15

7.3 Signalling interworking .......................................................................................................18

7.4 Numbering .........................................................................................................................18

7.5 Supplementary service interworking..................................................................................18

8 Compatibility and subscription checking ...........................................................................................18

9 Interworking to PSTN ........................................................................................................................18

9.1 Speech Calls......................................................................................................................18

9.1.1 Interworking indications to PLMN terminal....................................................18

9.1.2 Transmission aspects ...................................................................................18

9.1.3 Generation of In-band Tones and Announcements (PLMN-PSTN)..............18

9.2 Data Calls ..........................................................................................................................19

9.2.1 Network interworking mobile originated ........................................................19

9.2.1.1 Selection of interworking function........................................19

9.2.1.2 Modem Selection.................................................................19

9.2.1.3 DTE/Modem interface (Filtering) .........................................20

9.2.1.4 Mapping of BC-IE from GSM 04.08 to ISUP (or other)........21

9.2.2 Network Interworking Mobile terminated PSTN Originated...........................21

9.2.3 Transparent service support .........................................................................25

9.2.3.1 Not used ..............................................................................25

9.2.3.2 Rate adaptation process in MSC/IWF .................................25
9.2.3.3 Mapping of signalling MS/MSC/IWF to modem interface

requirements........................................................................25

9.2.3.4 Establishment of end-to-end terminal synchronizations ......26
9.2.3.5 Network Independent Clocking (NIC)..................................27

9.2.4 Non-transparent service support...................................................................27

9.2.4.1 MSC-IWF Rate adaptation scheme.....................................27
9.2.4.2 Protocol layer structure in the MSC/IWF .............................27

9.2.4.3 Re-constitution of user data.................................................27

9.2.4.4 Layer 2 relay functionality ....................................................28

9.2.4.5 In band signalling mapping flow control...............................28
9.2.4.5.1 Conditions requiring flow control
towards the fixed network .....................28
9.2.4.5.2 Conditions requiring flow control
towards the MS.....................................29
---------------------- Page: 5 ----------------------
SIST ETS 300 604 E6:2003
Page 4
ETS 300 604 (GSM 09.07 version 4.12.1): May 1997

9.2.4.6 Data buffers ........................................................................ 29

9.2.4.6.1 Transmit buffers (towards MS)............. 29
9.2.4.6.2 Receive buffers (from MS) ................... 29

9.2.4.7 Transportation of the Break condition................................. 29

9.2.4.8 In band signalling mapping modem status information....... 29

9.2.4.9 Support of out-band flow control ......................................... 30

9.2.4.10 Establishment of end-to-end terminal synchronizations ..... 30

9.3 Interworking Alternate Speech / Data Calls....................................................................... 31

9.3.1 Alternate Speech/Data Interworking............................................................. 31

9.3.1.1 General ............................................................................... 31

9.3.1.2 Mobile originated PSTN terminated calls............................ 31
9.3.1.3 PSTN originated mobile terminated calls............................ 31

9.3.2 Speech followed by data interworking .......................................................... 32

9.3.2.1 General ............................................................................... 32

10 Interworking to the ISDN................................................................................................................... 32

10.1 Speech Calls ..................................................................................................................... 32

10.2 Data Calls.......................................................................................................................... 32

10.2.1 Network interworking mobile originated........................................................ 33

10.2.1.1 Circuit switched calls........................................................... 33

10.2.1.2 Packet calls......................................................................... 33

10.2.2 Network interworking mobile terminated ...................................................... 33

10.2.2.1 Circuit switched calls........................................................... 48

10.2.2.2 Packet calls......................................................................... 48

10.2.3 Transparent service support (see GSM 03.10) ............................................ 48

10.2.3.1 MSC - IWF rate adaptation scheme ................................... 48
10.2.3.2 Rate adaptation process in MSC/IWF ................................ 48
10.2.3.3 Mapping of signalling MS/MSC/IWF to modem interface

requirements ....................................................................... 48

10.2.3.4 Establishment of end-to-end terminal synchronizations ..... 49
10.2.3.5 Network independent Clocking (NIC).................................. 50

10.2.4 Non-transparent service support (see GSM 03.10)...................................... 50

10.2.4.1 MSC - IWF Rate adaptation scheme.................................. 50
10.2.4.2 Protocol layer structure in the MSC/IWF............................. 50

10.2.4.3 Re-constitution of user data ................................................ 50

10.2.4.4 Layer 2 relay functionality.................................................... 50

10.2.4.5 In band signalling mapping flow control .............................. 51

10.2.4.5.1 Conditions requiring flow control - if
flow control is provided - towards the
fixed network ........................................ 51
10.2.4.5.2 Conditions requiring flow control
towards the MS .................................... 51

10.2.4.6 Data buffers ........................................................................ 52

10.2.4.6.1 Transmit buffers (towards MS)............. 52
10.2.4.6.2 Receive buffers (from MS) ................... 52

10.2.4.7 BREAK Indication................................................................ 52

10.2.4.8 Signalling mapping modem status information or in band
rate adapted frame information........................................... 52

10.2.4.9 Support of out-band flow control ......................................... 52

10.2.4.10 Synchronizations................................................................. 52

10.2.4.10.1 V110 Frame synchronizations.............. 52
10.2.4.10.2 RLP Frame start indication................... 52
10.2.4.10.3 L2R Frame synchronizations................ 52
10.2.4.10.4 Establishment of end-to-end terminal
synchronizations................................... 53

10.2.5 DTE/Modem interface (Filtering) .................................................................. 53

10.3 Interworking Alternate speech data calls .......................................................................... 54

10.3.1 Alternate speech data bearer interworking................................................... 55

10.3.1.1 General ............................................................................... 55

10.3.1.2 Mobile originated ISDN terminated ..................................... 55

10.3.1.3 ISDN originated mobile terminated ..................................... 55

10.3.2 Speech followed by data interworking .......................................................... 56

10.3.2.1 General ............................................................................... 56

---------------------- Page: 6 ----------------------
SIST ETS 300 604 E6:2003
Page 5
ETS 300 604 (GSM 09.07 version 4.12.1): May 1997

11 V.110 Frame Synchronization ...........................................................................................................56

11.1 Initial V.110 frame synchronization ....................................................................................56

11.2 Action on loss of V.110 frame synchronization for non transparent services ....................56

11.3 Action on loss of V.110 frame synchronization for transparent services ...........................56

Annex A (informative): SDLs...................................................................................................................58

History..........................................................................................................................................................60

---------------------- Page: 7 ----------------------
SIST ETS 300 604 E6:2003
Page 6
ETS 300 604 (GSM 09.07 version 4.12.1): May 1997
Blank page
---------------------- Page: 8 ----------------------
SIST ETS 300 604 E6:2003
Page 7
ETS 300 604 (GSM 09.07 version 4.12.1): May 1997
Foreword

This European Telecommunication Standard (ETS) has been produced by the Special Mobile Group

(SMG) Technical Committee of the European Telecommunications Standards Institute (ETSI).

This ETS identifies the Mobile-services Switching Centre (MSC) Interworking Functions (IWFs) and

requirements to support interworking between:

a) Public Land Mobile Network (PLMN) and Public Switched Telephone Network (PSTN);

b) PLMN and Integrated Services Digital Network (ISDN).
This ETS corresponds to GSM technical specification GSM 09.07 version 4.12.1

The specification from which this ETS has been derived was originally based on CEPT documentation,

hence the presentation of this ETS may not be entirely in accordance with the ETSI/PNE Rules.

Reference is made within this ETS to GSM-TSs (note).

Reference is also made within this ETS to GSM xx.xx. series. The specifications in the series can be

identified, with their full title, within the normative reference clause of this ETS by the first two digits of their

GSM reference number e.g. GSM 09.xx series, refers to GSM 09.01, GSM 09.02, etc.
Transposition dates
Date of adoption: 4 April 1997
Date of latest announcement of this ETS (doa): 31 August 1997
Date of latest publication of new National Standard
or endorsement of this ETS (dop/e): 28 February 1998
Date of withdrawal of any conflicting National Standard (dow): 28 February 1998
---------------------- Page: 9 ----------------------
SIST ETS 300 604 E6:2003
Page 8
ETS 300 604 (GSM 09.07 version 4.12.1): May 1997
Blank page
---------------------- Page: 10 ----------------------
SIST ETS 300 604 E6:2003
Page 9
ETS 300 604 (GSM 09.07 version 4.12.1): May 1997
1 Scope

The purpose of this European Telecommunication Standard (ETS) is to identify the Mobile-services

Switching Centre (MSC)/Interworking Functions (IWFs) and requirements to support interworking

between:
i) PLMN and PSTN;
ii) PLMN and ISDN.

It is not possible to treat ISDN and PSTN as one type of network, even when both ISDN and PSTN

subscribers are served by the same exchange because of the limitations of the PSTN subscribers access

i.e. analogue connection without D-channel signalling.

Within this ETS, the requirements for voice and non-voice (data) calls are considered separately.

2 Normative references

This ETS incorporates by dated and undated reference, provisions from other publications. These

normative references are cited at the appropriate places in the text and the publications are 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 referred to applies.
[1] CCITT Recommendation G.711: "Pulse code modulation (PCM) of voice
frequencies".
[2] CCITT Recommendation I.460: "Multiplexing, rate adaption and support of
existing interfaces".
[3] CCITT Recommendation V.25: "Automatic answering equipment and/or parallel
automatic calling equipment on the general switched telephone network
including procedures for disabling of echo control devices for both manually and
automatically established calls".
[4] CCITT Recommendation V.110: "Support of data terminal equipments (DTEs)
with V-series interfaces by an integrated services digital network".
[5] ETS 300 102-1 Edition 1: "Integrated Services Digital Network (ISDN);
User-network interface layer 3 Specifications for basic call control".
[6] ETS 300 121: "Integrated Services Digital Network (ISDN); Application of the
ISDN User Part (ISUP) of CCITT Signalling System No.7 for international ISDN
interconnections (ISUP version 1)".
[7] GSM 01.04 (ETR 100): "Digital cellular telecommunications system (Phase 2);
Abbreviations and acronyms".
[8] GSM 02.01 (ETS 300 500): "Digital cellular telecommunications system
(Phase 2); Principles of telecommunications services supported by a GSM
Public Land Mobile Network (PLMN)".
[9] GSM 02.02 (ETS 300 501): "Digital cellular telecommunications system
(Phase 2); Bearer Services (BS) supported by a GSM Public Land Mobile
Network (PLMN)".
[10] GSM 02.03 (ETS 300 502): "Digital cellular telecommunications system
(Phase 2); Teleservices supported by a GSM Public Land Mobile Network
(PLMN)".
[11] GSM 02.04 (ETS 300 503): "Digital cellular telecommunications system
(Phase 2); General on supplementary services".
---------------------- Page: 11 ----------------------
SIST ETS 300 604 E6:2003
Page 10
ETS 300 604 (GSM 09.07 version 4.12.1): May 1997
[12] GSM 02.81 (ETS 300 514): "Digital cellular telecommunications system
(Phase 2); Line identification supplementary services - Stage 1".
[13] GSM 02.82 (ETS 300 515): "Digital cellular telecommunications system
(Phase 2); Call Forwarding (CF) supplementary services - Stage 1".
[14] GSM 02.83 (ETS 300 516): "Digital cellular telecommunications system
(Phase 2); Call Waiting (CW) and Call Hold (HOLD) supplementary services -
Stage 1".
[15] GSM 02.84 (ETS 300 517): "Digital cellular telecommunications system
(Phase 2); MultiParty (MPTY) supplementary services - Stage 1".
[16] GSM 02.85 (ETS 300 518): "Digital cellular telecommunications system
(Phase 2); Closed User Group (CUG) supplementary services - Stage 1".
[17] GSM 02.86 (ETS 300 519): "Digital cellular telecommunications system
(Phase 2); Advice of charge (AoC) supplementary services - Stage 1".
[18] GSM 02.88 (ETS 300 520): "Digital cellular telecommunications system
(Phase 2); Call Barring (CB) supplementary services - Stage 1".
[19] GSM 03.03 (ETS 300 523): "Digital cellular telecommunications system
(Phase 2); Numbering, addressing and identification".
[20] GSM 03.08 (ETS 300 526): "Digital cellular telecommunications system
(Phase 2); Organization of subscriber data".
[21] GSM 03.11 (ETS 300 529): "Digital cellular telecommunications system
(Phase 2); Technical realization of supplementary services".
[22] GSM 03.45 (ETS 300 538): "Digital cellular telecommunications system
(Phase 2); Technical realization of facsimile group 3 transparent".
[23] GSM 03.46 (ETS 300 539): "Digital cellular telecommunications system
(Phase 2); Technical realization of facsimile group 3 non-transparent".
[24] GSM 03.50 (ETS 300 540): "Digital cellular telecommunications system
(Phase 2); Transmission planning aspects of the speech service in the GSM
Public Land Mobile Network (PLMN) system".
[25] GSM 04.08 (ETS 300 557): "Digital cellular telecommunications system
(Phase 2); Mobile radio interface layer 3 specification".
[26] GSM 04.21 (ETS 300 562): "Digital cellular telecommunications system
(Phase 2); Rate adaption on the Mobile Station - Base Station System (MS -
BSS) Interface".
[27] GSM 04.22 (ETS 300 563): "Digital cellular telecommunications system
(Phase 2); Radio Link Protocol (RLP) for data and telematic services on the
Mobile Station - Base Station System (MS - BSS) interface and the Base Station
System - Mobile-services Switching Centre (BSS - MSC) Interface".
[28] GSM 07.01 (ETS 300 582): "Digital cellular telecommunications system
(Phase 2); General on Terminal Adaptation Functions (TAF) for Mobile Stations
(MS)".
[29] GSM 07.02 (ETS 300 583): "Digital cellular telecommunications system
(Phase 2); Terminal Adaptation Functions (TAF) for services using
asynchronous bearer capabilities".
---------------------- Page: 12 ----------------------
SIST ETS 300 604 E6:2003
Page 11
ETS 300 604 (GSM 09.07 version 4.12.1): May 1997
[30] GSM 07.03 (ETS 300 584): "Digital cellular telecommunications system
(Phase 2); Terminal Adaptation Functions (TAF) for services using synchronous
bearer capabilities".
[31] GSM 07.05 (ETS 300 585): "Digital cellular telecommunications system
(Phase 2); Use of Data Terminal Equipment - Data Circuit terminating
Equipment (DTE - DCE) interface for Short Message Service (SMS) and Cell
Broadcast Service (CBS)".
[32] GSM 08.20 (ETS 300 591): "Digital cellular telecommunications system
(Phase 2); Rate adaption on the Base Station System - Mobile-services
Switching Centre (BSS - MSC) interface".
[33] GSM 08.60 (ETS 300 597): "Digital cellular telecommunications system
(Phase 2); Inband control of remote transcoders and rate adaptors for full rate
traffic channels".
[34] GSM 09.02 (ETS 300 599): "Digital cellular telecommunications system
(Phase 2); Mobile Application Part (MAP) specification".
[35] GSM 09.03 (ETS 300 600): "Digital cellular telecommunications system
(Phase 2); Signalling requirements on interworking between the Integrated
Services Digital Network (ISDN) or Public Switched Telephone Network (PSTN)
and the Public Land Mobile Network (PLMN)".
[36] GSM 09.05 (ETS 300 602): "Digital cellular telecommunications system
(Phase 2); Interworking between the Public Land Mobile Network (PLMN) and
the Packet Switched Public Data Network (PSPDN) for Packet
Assembly/Disassembly facility (PAD) access".
[37] GSM 09.06 (ETS 300 603): "Digital cellular telecommunications system
(Phase 2); Interworking between a Public Land Mobile Network (PLMN) and a
Packet Switched Public Data Network/Integrated Services Digital Network
(PSPDN/ISDN) for the support of packet switched data transmission services".

NOTE: As regards ETS 300 102-1 [5], the edition 1 of this ETS from 1990 shall be used, with

one exception: the encoding of the field modem type in the ISDN BC-IE shall be
handled as specified in table 6A and 6B of GSM 09.07.
---------------------- Page: 13 ----------------------
SIST ETS 300 604 E6:2003
Page 12
ETS 300 604 (GSM 09.07 version 4.12.1): May 1997
3 Definitions and abbreviations

Use is made of the following terms within this ETS. These terms refer to information requirements

necessary to support interworking functions, some of these terms will be identifiable with their use in other

GSM specifications.
For the purposes of this ETS, the following definitions apply:

bearer capability information: Specific information defining the lower layer characteristics required

within the network.

low layer compatibility information: Information defining the lower layer characteristics of the terminal.

high layer compatibility information: Information defining the higher layer characteristics of the

terminal.

compatibility information: This term subsumes the entirety of Bearer Capability, Low Layer

Compatibility, High Layer Compatibility, Progress Indicator and Address Information conveyed out-of-band

prior to call establishment for the support of compatibility checking and terminal/function/service selection

at the ISDN-type user-network interface.

protocol identifier: Information defining the specific protocols utilized for the support of data transfer by a

terminal.

progress indicator: Information supplied to indicate to the terminal that network interworking has taken

place.

out-of-band parameter exchange: Information exchanged via an associated or non-associated

signalling link e.g. SS No 7.
PSTN: Subscriber to network interface supports only analogue terminals.

ISDN: Subscriber to network interface supports digital or analogue terminals, plus a standardized user to

network associated signalling system and a standardized internetwork signalling system.

autobauding type 1: This information element value may be contained in the setup or call confirm

messages from the mobile station in association with a non transparent data service. This implies that the

MSC/IWF may select any speed and modem type according to what it can negotiate with the remote

modem on the PSTN/ISDN. The maximum speed to be used by the MSC/IWF is the user speed indicated

in the setup/call confirm message.

multi self selecting speed modem: This term applies to V series modems capable of handling one or

more lower speeds as a fall back position. When such a modem is requested in the call setup or call

confirm message from the MS in association with a non transparent service, the MSC/IWF may select any

of the speeds supported according to the negotiation with the remote modem on the PSTN/ISDN. In this

instance the maximum starting negotiation speed to be used by the MSC/IWF is the one indicated by the

user speed in the setup/call confirm message.

In addition to those below abbreviations used in this ETS are listed in GSM 01.04.

ADPCM Adaptive Differential Pulse Coded Modulation
DP Dial Pulse
ITC Information Transfer Capability
LE Local Exchange
NT Network Termination
PABX Private Automatic Branch Exchange
SPC Stored Program Control
SS No.7 Signalling System No.7
TE Terminal Equipment
TA Terminal Adaptor
TUP Telephone User Part (of Signalling System No.7)
DSS1 Digital Subscriber Signalling 1
UNI User Network Interface
---------------------- Page: 14 ----------------------
SIST ETS 300 604 E6:2003
Page 13
ETS 300 604 (GSM 09.07 version 4.12.1): May 1997
4 Introduction

General Network Interworking Scenarios are described in GSM 09.01. Since the numbering plan for the

ISDN era (E.164) includes the numbering plan for the telephone network (E.163), it is not possible to

distinguish by the number whether a given subscriber is a PSTN or ISDN subscriber. Further, in some

countries both PSTN and ISDN subscribers will be connected to the same exchange, so the only

difference for this type of combined network will be in the nature of the customer access. In this document

a PSTN is considered to support only an analogue interface towards the subscriber. An ISDN shall be

considered to support digital interface towards the subscriber. In addition, the ISDN is considered to

support a standardized outband signalling protocol both between the subscriber and the network and

within the network, i.e. DSS1 and ISUP, thus enabling the generation and transport of Compatibility

Information for compatibility checking and terminal/function/service selection at the user-network interface

as well as for MSC/IWF selection.

There now exist networks which do not fall into either of these categories in that they provide for digital

connectivity from subscriber to subscriber through the network. The subscribers have access to a wide

range of services by a limited set of standard multi-purpose user network interfaces. However, these

networks do not support the standardized inter-exchange signalling protocol throughout, in that they are

e.g. using TUP or National User Part (NUP). These types of network support 64 kbit/s connections, so in

service support are comparable to ISDN, however, the signalling system provided may not support

transport of all Compatibility Information allowed for in the standardized ISDN signalling. This document

will therefore identify interworking to PSTN and ISDN on the principle of the network characteristics as

identified in the previous paragraph. The aforementioned existing networks then constitute one particular

case in the ISDN interworking scenarios. These cases will be itemized when the implication of the various

degrees of exhaustiveness of the Compatibility Information - delivered via the ISDN - used for deducting a

GSM Basic Service needs to be set forth.

When two dissimilar networks are required to interwork in order to support a communication between two

subscribers, one on each network, a number of Interworking Functions (MSC/IWFs) are required to

support the communication. Some of these are related to the differences in signalling and are dealt with in

GSM 09.03.
Examples of other aspects of interworking are:
i) the need or otherwise of echo control devices;
ii)
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.