hlr

HLR - HLR SSAP Version 1Interface Specification

DN99633396Issue 6-0 en

# Nokia Siemens Networks 1 (19)

MSCDOCM14PDFCDMSC/HLR, Rel. M14.1, Product Documentation,v.1

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2 (19) # Nokia Siemens Networks DN99633396Issue 6-0 en

HLR - HLR SSAP Version 1 Interface Specification

Contents

Contents 3

List of tables 4

1 Introduction 5

2 Interface modifications 72.1 General description 72.2 Changes of interface after previous release 7

3 Interface description 93.1 Dialogue procedures 93.2 CCBS Operations 93.3 Parameters 103.4 Support of CCBS operation parameters 113.4.1 Operations 113.4.1.1 CcbsRequest 113.4.1.2 CcbsCancel 123.4.1.3 RemoteUserFree, CcbsSuspend, and CcbsResume 123.5 Restrictions 133.5.1 Restrictions to charging 133.5.2 Restrictions to statistics 13

4 Support protocol description 15

Glossary 17

References 19



Contents

List of tables

Table 1. The SSAP dialogue procedures. 9

Table 2. The CCBS operations. 10

Table 3. The SSAP parameters. 10

Table 4. The CcbsRequest operation (ETS 300 356-18, Table C.1). 11

Table 5. The CcbsCancel operation (ETS 300 356-18, Table C.1). 12

Table 6. The RemoteUserFree, CcbsSuspend, and CcbsResume operation (ETS300 356-18, Table C.1). 12

Table 7. The coding of subscriber B's address in the SCCP. 15



1 Introduction

The purpose of this document is to describe the Supplementary ServiceApplication Part (SSAP) interface between the originating and target HLR.

The SSAP is an interface protocol which provides the signalling functionsbetween the originating and target exchange for the Completion of Calls toBusy Subscribers (CCBS) supplementary service.

The SSAP uses the services provided by the Transaction CapabilityApplication Part (TCAP) to transfer information between originating andtarget HLR.

This document covers the Supplementary Service Application Part (SSAP)specified by the European Telecommunication Standards Institute (ETSI)in ETS 300 356-18 (February 1995).



Introduction

2 Interface modifications

2.1 General description

The HLR - HLR SSAP Version 1 is an interface which uses the servicesprovided by the Transaction Capability Application Part (TCAP) to transferinformation between the originating and target HLR. The SSAP interfaceprotocol provides the signalling functions between the originating andtarget exchange for the Call Completion to Busy Subscriber (CCBS)supplementary service.

2.2 Changes of interface after previous release

No changes have been implemented in the interface since the previousrelease.



Interface modifications

3 Interface description

3.1 Dialogue procedures

The Supplementary Service Application Part (SSAP) dialogue proceduresare introduced in the following table.

The following abbreviations are used in the table below:

D descriptive text

S supported

Table 1. The SSAP dialogue procedures.

Reference

ETS 300 356-18

Nokia's support

9.9 Dialogue D

9.9.1 General D

9.9.2 Dialogue beginning S

9.9.3 Dialogue continuation S

9.9.4 Dialogue end S

3.2 CCBS Operations

The following abbreviation is used in the table below:

S supported



Interface description

Table 2. The CCBS operations.

CCBS Operation Reference

ETS 300 356-18

Nokia's support

CcbsRequest 9.1 S

CcbsCancel 9.1 S

RemoteUserFree 9.2 S

CcbsSuspend 9.2 S

CcbsResume 9.2 S

3.3 Parameters

The following abbreviations are used in the table below:

S supported

PS partially supported

NS not supported

Table 3. The SSAP parameters.

Parameter Reference

ETS 300 356-18

Nokia's support

calledPartyNumber Table C.1 ¹) S

retainSupported Table C.1 S

userServiceInf Table C.1 ¹) S

callingPartyNumber Table C.1 ¹) NS

userServiceInfPrime Table C.1 ¹) NS

accessTransportParameter Table C.1 ²) PS ³)

cancelCause Table C.1 S



Note

1. The parameter is structured as described in ITU-TRecommendations Q.763 (1999), Specifications of SignalingSystem No.7.

2. The parameter is structured as described in ITU-TRecommendations Q.931 (1998), Digital Subscriber SignalingSystem No.1; Network Layer.

3. The High Layer Compatibility (HLC), Lower Layer Compatibility(LLC), and called party subaddress are present. The calling partysubaddress is not present.

3.4 Support of CCBS operation parameters

The following abbreviations are used in the tables below:

M mandatory parameter

O optional parameter

S supported

PS partially supported

NS not supported

3.4.1 Operations

3.4.1.1 CcbsRequest

Table 4. The CcbsRequest operation (ETS 300 356-18, Table C.1).

ETSI use Nokia's support

Invocation Parameters

calledPartyNumber M S

retainSupported M S

userServiceInf O S

callingPartyNumber O NS

userServiceInfPrime O NS




Table 4. The CcbsRequest operation (ETS 300 356-18, Table C.1). (cont.)

ETSI use Nokia's support

accessTransportParameter O PS ¹)

Result Parameters

retainSupported M S

Error Causes

ShortTermDenial M S

LongTermDenial M S

Note

1. The calling party subaddress is not present.

3.4.1.2 CcbsCancel

Table 5. The CcbsCancel operation (ETS 300 356-18, Table C.1).

Parameter ETSI use Nokia's support

cancelCause O S

3.4.1.3 RemoteUserFree, CcbsSuspend, and CcbsResume

Table 6. The RemoteUserFree, CcbsSuspend, and CcbsResume operation(ETS 300 356-18, Table C.1).

Parameter ETSI use Nokia's support

(no parameters)



3.5 Restrictions

3.5.1 Restrictions to charging

When the SSAP connection is used, the length of the connection is notchargeable. Fixed charging can be used to charge the initiation of theconnection.

3.5.2 Restrictions to statistics

The SSAP protocol statistics can only be measured in the originating anddestination signalling points. No statistics are available for transit signallingpoints where routing (of messages) is done on the MTP level.

It is not possible to distinguish the GSM type of CCBS from the ISDN typeof CCBS in the SSAP operation specific counters.




4 Support protocol description

The SSAP uses the services of the underlying layers: the TCAP(Transaction Capabilities Application Part) and SCCP (SignallingConnection Control Part). The TCAP used complies with the ITU-Trecommendations.

The SCCP service class is “1”, meaning that the messages are received inthe order they are sent. The SCCP return option is set to “return messageon error” by default.

For routing on the international interface and for routing based on theGlobal Title (GT) translation mechanism within national networks, thecoding of subscriber B's address in the SCCP complies with the followingrestrictions:

Table 7. The coding of subscriber B's address in the SCCP.

Variable Value Explanation

SSN indicator 1 SSN for ISDN supplementary services is alwaysincluded.

GT indicator 0100 Includes the translation type, numbering plan,encoding scheme, and nature of the address.

translation type 0001 0001 Translation table.

numbering plan 0001 ISDN/telephony numbering plan E.164.

routing indicator 0 Routing on global title.

For routing within a national network, the SCCP addressing method basedon the Signalling Point Codes (SPCs) may be used.

The subsystem number value 0000 1011 (0xB) is dedicated to the ISDNsupplementary services ASEs.



Support protocol description

Glossary

ApplicationServiceElement(ASE)

A set of functions that provides a capability for the interworking ofapplication entity invocations for a specific purpose on a single applicationassociation.

Completion ofCalls to BusySubscriber(CCBS)

A service which enables subscriber A who has called a busy line to havethe call completed automatically when the called line becomes free withouthaving to redial the called number.

Global Title(GT)

An address, such as digits dialled by the customer, which requires anaddress conversion before the messages are sent to Message TransferPart (MTP).

IntegratedServicesDigitalNetwork(ISDN)

Integrated services network that provides digital connections betweenuser-network interfaces.

SignallingConnectionControl Part(SCCP)

Part of CCS7 signalling; provides connectionless and connection-orientedservices to achieve compatibility with the Open Systems Interconnection(OSI) network layer.

Supplemen-tary ServiceApplicationPart (SSAP)

The SSAP is an interface protocol which provides the signaling functionsbetween the originating and target exchange for the Call Completion toBusy Subscriber (CCBS) and Completion of Calls on No Reply (CCNR)supplementary services.

SubsystemNumber (SSN)

A number to identify a subsystem using the Signalling Connection ControlPart (SCCP) either directly, like the ISDN user part, or indirectly (via thetransaction capabilities) like the Operations, Maintenance andAdministration part (OMAP).

TransactionCapabilitiesApplicationPart (TCAP)

A part of the transaction capabilities that resides in the application layer ofthe OSI protocol references model.



Glossary

References

1. ETS 300 356-18 (February 1995) Integrated Services DigitalNetwork (ISDN); Signalling System No.7; ISDN User Part (ISUP)version 2 for the international interface; Part 18: Completion of Callsto Busy Subscribers (CCBS) supplementary service.

2. ITU-T Recommendations Q.763 (1999), Formats and codes of theISDN user part of Signalling System No. 7 .

3. ITU-T Recommendations Q.931 (1998), Digital SubscriberSignalling System No. 1 (DSS 1) - ISDN User-Network InterfaceLayer 3 Specification For Basic Call Control.



References

hlr

Documents

calling party subaddress

nokia siemens networks

ssap dialogue procedures

isdn user part

network layer

signalling system

supplementary service

interface protocol