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InformationRouting

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f Important Notice on Product SafetyElevated voltages are inevitably present at specific points in this electrical equipment. Some of theparts may also have elevated operating temperatures.Non-observance of these conditions and the safety instructions can result in personal injury or in prop-erty damage.Therefore, only trained and qualified personnel may install and maintain the system.The system complies with the standard EN 60950 / IEC 60950. All equipment connected has to complywith the applicable safety standards.

The same text in German:Wichtiger Hinweis zur ProduktsicherheitIn elektrischen Anlagen stehen zwangslufig bestimmte Teile der Gerte unter Spannung. Einige Teileknnen auch eine hohe Betriebstemperatur aufweisen.Eine Nichtbeachtung dieser Situation und der Warnungshinweise kann zu Krperverletzungen undSachschden fhren.Deshalb wird vorausgesetzt, dass nur geschultes und qualifiziertes Personal die Anlagen installiert undwartet.

Das System entspricht den Anforderungen der EN 60950 / IEC 60950. Angeschlossene Gertemssen die zutreffenden Sicherheitsbestimmungen erfllen.

Trademarks:All designations used in this document can be trademarks, the use of which by third parties for theirown purposes could violate the rights of their owners.

Copyright (C) Siemens AG 2004.Issued by the Information and Communication Networks GroupHofmannstrae 51D-81359 Mnchen

Technical modifications possible.Technical specifications and features are binding only insofar asthey are specifically and expressly agreed upon in a written contract.

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Reason for UpdateSummary:

Details:

Chapter/Section Reason for Update

Issue HistoryIssue Date of issue Reason for Update

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This document consists of a total of 169 pages. All pages are issue 1.

Contents1 Network structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101.1 Network nodes in the TDM Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101.2 Types of network. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111.2.1 Hierarchical networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111.2.2 Non-hierarchical networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121.2.3 Deregulated networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

2 Traffic Routing (RO) and Network Management (NT) . . . . . . . . . . . . . . . . 143 Digit Translation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163.1 Determination of a Destination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163.1.1 Digit Translation in LTG and CP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173.2 Traffic Restrictions and privileged Traffic . . . . . . . . . . . . . . . . . . . . . . . . . . 203.2.1 Traffic Restrictions due to Traffic Types . . . . . . . . . . . . . . . . . . . . . . . . . . . 203.2.2 Privileged Traffic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203.2.2.1 Traffic from privileged subscribers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213.2.2.2 Administration Hints and Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253.2.2.3 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263.2.2.4 Call charge registration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263.3 Multiple Local Networks in One Network Node. . . . . . . . . . . . . . . . . . . . . . 273.3.1 Mode of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283.3.1.1 Numbering and directory number volume. . . . . . . . . . . . . . . . . . . . . . . . . . 313.3.1.2 Numbering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333.3.1.3 Call charge registration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353.3.2 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363.3.3 Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363.4 Routing via other Carriers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 373.4.1 Mode of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 373.4.2 Charge registration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 423.4.3 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 423.4.4 Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 423.5 Traffic Control with the Carrier Access Code . . . . . . . . . . . . . . . . . . . . . . . 433.5.1 Mode of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 443.5.1.1 Zoning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 443.5.1.2 Black/White List Screening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 463.5.1.3 AMA Ticket Generation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 473.5.2 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 473.5.3 Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 473.6 Customer-Dependent Routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 483.6.1 Mode of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 483.6.2 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 503.6.3 Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 503.7 Local Number Portability (LNP, IN method) . . . . . . . . . . . . . . . . . . . . . . . . 513.7.1 Mode of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 523.7.2 Examples of call setups for bearer-related calls to ported subscribers . . . 56

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3.7.2.1 Query on digit analysis method (QoD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 563.7.2.2 Query on release method (QoR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 593.7.3 Setting up bearer-unrelated calls to ported subscribers . . . . . . . . . . . . . . . 643.7.4 Subscriber procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 643.7.5 Traffic measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 643.7.6 Call charge registration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 643.7.7 Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 653.7.8 Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 653.8 Second Directory Number per Subscriber or PBX . . . . . . . . . . . . . . . . . . . 673.8.1 Mode of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 673.8.1.1 Network-wide common directory number. . . . . . . . . . . . . . . . . . . . . . . . . . . 683.8.1.2 Location number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 693.8.2 Call charge registration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 703.8.3 Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 703.8.4 Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 703.9 Code Blocking Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 713.9.1 Call Gapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 713.9.2 Code Blocking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 743.9.3 Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 753.10 Call Gapping and Code Blocking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 763.10.1 Call Gapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 763.10.1.1 Mode of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 763.10.1.2 Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 763.10.2 Code Blocking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 783.10.2.1 Mode of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 783.10.3 Administration Hints for Static Blocking Points . . . . . . . . . . . . . . . . . . . . . . 793.11 Leaky Bucket . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 803.11.1 Mode of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 803.11.2 Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 833.11.3 Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

4 Destinations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 844.1 A-Number-Dependent Traffic Routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 854.1.1 Mode of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 854.1.1.1 A-number screening for subscriber identification . . . . . . . . . . . . . . . . . . . . . 864.1.1.2 A-number screening for special traffic routing . . . . . . . . . . . . . . . . . . . . . . . 874.1.1.3 A-number screening for special zoning . . . . . . . . . . . . . . . . . . . . . . . . . . . . 874.1.1.4 Black/White List Screening due to signalled CAC . . . . . . . . . . . . . . . . . . . . 884.1.1.5 Compatibility. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 894.1.1.6 Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 894.1.2 Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 894.2 Traffic distribution among several carriers (Carrier Quota) . . . . . . . . . . . . . 904.2.1 Mode of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 904.2.1.1 Example of a call setup using the feature Carrier Selection via Quota Groups

924.2.2 Adminstration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 934.3 Call Divergence Destination (CDD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 944.3.1 Mode of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

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4.3.2 Call charge registration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 954.3.3 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 964.3.4 Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 964.4 Destination Areas with Transmission-Optimized Routing (TMR/IPI) . . . . . 974.4.1 Mode of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 984.4.2 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1024.4.3 Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1024.5 Hard to Reach Control (HTRC). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1034.5.1 Mode of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1044.5.2 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1064.5.3 Administration Hints and Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1074.6 Mass Call Control (MCC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1084.6.1 Mode of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1094.6.2 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1134.6.3 Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

5 Routes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1145.1 Automatic Alternative Routing and Automatic Rerouting . . . . . . . . . . . . . 1155.1.1 Automatic alternative routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1165.1.2 Automatic Rerouting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1195.1.3 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1215.1.4 Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1215.2 Route Switchover (Time Dependant Routing) . . . . . . . . . . . . . . . . . . . . . 1225.2.1 Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1225.3 Route Threshold Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1235.3.1 Description of the Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1235.3.2 Safeguarding the Data Consistency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1245.3.3 Adminstration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1245.4 Flexible Routing via PBX-Lines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1255.4.1 Mode of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1265.4.2 Interworking with other Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1275.4.2.1 Routing Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1275.4.2.2 General Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1275.4.3 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1285.4.4 Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1285.5 Optimized Dynamic Routing (ODR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1295.5.1 Mode of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1305.5.1.1 Automatic recognition of the current load situation . . . . . . . . . . . . . . . . . . 1315.5.1.2 Adaptive routing with distribution of overload traffic to less heavily loaded al-

ternative routes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1315.5.1.3 Optimized Dynamic Routing and Trunk Groups (Trunk Group Clusters) . 1325.5.1.4 Rerouting Function in Non-Hierarchical Networks . . . . . . . . . . . . . . . . . . 1335.5.1.5 Dependencies on other Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1335.5.2 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1345.5.3 Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134

6 Trunk Groups and Trunks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1356.1 Operating Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136

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6.1.1 Incoming Trunk Groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1366.1.2 Outgoing Trunk Groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1376.1.3 Bothway Trunk Groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1376.1.4 Trunk Groups for voice channels and/or signaling channels . . . . . . . . . . . 1376.1.5 Routing based on the signal delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1386.2 Trunks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1386.2.1 Routing Features for Trunk Groups and Trunks . . . . . . . . . . . . . . . . . . . . 1396.3 Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1396.4 Access of Announcements via Announcement Groups and Announcement

Lines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1406.4.1 Announcements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1406.4.2 Announcement Groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1406.4.3 Announcement lines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1416.4.4 Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1416.5 Trunk Group Cluster and Proportional Bidding . . . . . . . . . . . . . . . . . . . . . 1426.5.1 Trunk Group Cluster. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1426.5.2 Proportional Bidding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1436.5.2.1 Mode of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1446.5.3 Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1456.5.4 Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1456.6 Selective Circuit Reservation (SCR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1466.6.1 Mode of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1466.6.1.1 Reservation levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1476.6.1.2 Traffic criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1476.6.1.3 Privileged subscriber traffic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1506.6.2 Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1506.6.3 Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1506.7 Network Management Controls (NMC) . . . . . . . . . . . . . . . . . . . . . . . . . . . 1516.7.1 Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1516.8 Automatic Congestion Control (ACC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1526.8.1 Mode of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1536.8.2 Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1546.8.3 Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

7 Network Traffic Management Center (NTMC) . . . . . . . . . . . . . . . . . . . . . . 1557.1 Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155

8 Intelligent Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1568.1 Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1578.2 SS7 Overload Control for IN Traffic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1588.2.1 Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158

9 Quality of service control in the IP network . . . . . . . . . . . . . . . . . . . . . . . . 1599.1 Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

10 Interception of Call Attempts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16010.1 General operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16210.2 Actions initiated by intercept code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16410.2.1 Continuing call setup (even though intercept code is selected) . . . . . . . . . 16410.2.2 Terminating call setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

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10.2.3 Inserting an audible tone. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16510.2.4 Combination of announcements and tones . . . . . . . . . . . . . . . . . . . . . . . 16510.2.5 Repeat digit translation and routing administration. . . . . . . . . . . . . . . . . . 16510.2.6 Repeat addressing of digit translation. . . . . . . . . . . . . . . . . . . . . . . . . . . . 16610.2.7 Preventing unauthorized repeat seizure . . . . . . . . . . . . . . . . . . . . . . . . . . 16610.2.8 Further options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16610.2.9 Particular features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16710.3 Administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167

11 Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169

10 A30828-X1178-G200-1-7618


1 Network structure

1.1 Network nodes in the TDM NetworkThe nodes in a network consist of the following types of network node (see Fig. 1.1): Local network node Transit network node Gateway network node

Fig. 1.1 Call involving an originating local network node, a transit network node anda terminating local network node

Local network nodeThe local network node is the network node where the lines of subscribers in a particularlocal area terminate. There may be more than one local network node serving a localarea. The local network nodes set up connections for calls within the local area and for-ward requests for calls to destinations outside this area to the transit network node.

Transit network nodeTransit network nodes set up connections for long-distance calls between different localareas.

Gateway network nodeGateway network nodes are the point of access between networks in different countries(for international calls) or between networks run by different operators in the same coun-try (where the national network has been deregulated).

Operator A

Localex-

change

Localex-

change

Transitex-

changecalling

subscribercalled

subscriber

Operator Bcalled

subscriber

Gatewayex-

change

Localex-

change

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1.2 Types of networkThere are two basic types of network: Hierarchical networks Non-hierarchical networksNetwork deregulation and the migration of voice and data networks place special de-mands on traffic routing.

1.2.1 Hierarchical networksIn hierarchical networks, network nodes are assigned to different levels of the networkin accordance with the type of traffic they switch.There are links between adjacent network nodes on the same level of the network andbetween network nodes on adjacent levels of the network hierarchy.Traffic is controlled by means of static routing.

Fig. 1.2 Hierarchical network

National level Nationalgateway net-work node

Transitnetwork

node

Transitnetwork

nodeLocal level

Local net-work node

Local net-work node

PBXPBX

12 A30828-X1178-G200-1-7618


1.2.2 Non-hierarchical networksIn non-hierarchical networks (see Fig. 1.3), there are equal-ranking links between allnetwork nodes. These networks avoid the disadvantages of hierarchical networks withtheir static traffic routing. Here, all trunk groups are dimensioned for a high load, the op-timum overflow sequences are defined as a function of the load and are found automat-ically by means of intelligent routing principles.

Fig. 1.3 Non-hierarchical network

National level

Local level

Local net-work node

PBXPBX

Gatewaynetwork

node

Gatewaynetwork

node

Local net-work node

Gatewaynetwork

node

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1.2.3 Deregulated networksA characteristic feature of deregulated networks is that they contain a large number oftransition points (gateways) between the networks run by different operators. Fig. 1.4shows the routing of a call that passes through several networks run by different opera-tors via gateway network nodes in a deregulated national network (see also section3.4 "Routing via other Carriers").

Fig. 1.4 Traffic routing through a deregulated network

Local area1

Local area2

OperatorA

OperatorB

Gatewaynetwork

node09888

Gatewaynetwork

node09555

Localnetwork

node09222

Localnet-worknode

Gate-way net-

worknode

Gate-waynet-worknode

callingsubscriber

calledsubscriber

14 A30828-X1178-G200-1-7618


2 Traffic Routing (RO) and Network Manage-ment (NT)During call setup from the calling Subscriber to the called subscriber, traffic routing eval-uates the dialed digits and works out an available connection path.EWSD has some very powerful routing (RO) functions, making optimum use of the avail-able network resources, and therefore has no problem in coping with large volumes oftraffic.The function of network management (NT) is, in the event of high load phases or failureof network sections, to make sure that the number of successful, charge generating connections does

not drop more than necessary to guarantee the highest possible setup quality for subscribersThe routing and network management features that are provided from EWSD are sub-divided into the following groups: Routing and Network Management features that deal with the evaluation of the in-

coming digits; the basic functions for digit analyzing are depicted in section3.1 "Determination of a Destination": Special Identifiers, (Basic feature depicted in OMN:EXCH-RO/NT) Splitting and Merging Code Points, (Basic feature depicted in OMN:EXCH-

RO/NT) Origin Dependent Routing, (Basic feature depicted in OMN:EXCH-RO/NT) Origin-Dependent Routing for Emergency Calls and Services in RSU Stand

Alone Service (SAS), (Basic feature depicted in OMN:EXCH-RO/NT) Ambiguous code points with identical starting digits and different destinations,

(Basic feature depicted in OMN:EXCH-RO/NT) Multiple Local Networks in One Network Node Traffic Restrictions and privileged Traffic Routing via other Carriers Traffic Control with the Carrier Access Code Customer-Dependent Routing Local Number Portability (LNP, IN method) Traffic Restrictions and privileged Traffic Code Blocking Points Call Gapping Code Blocking Leaky Bucket

Routing and Network Management features that handle with the different kind ofdestinations that are provided from EWSD: Destinations with Digit Retranslation, (Basic feature depicted in OMN:EXCH-

RO/NT) A-Number-Dependent Traffic Routing A-number screening for subscriber identification A-number screening for special traffic routing Fraud Prevention (command path: BLSTWLST) , depicted in OMN:EXCH-

RO/NT) Traffic distribution among several carriers (Carrier Quota) Call Divergence Destination (CDD) Destination Areas with Transmission-Optimized Routing (TMR/IPI)

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Hard to Reach Control (HTRC) Mass Call Control (MCC)

Routing and Network Management features that handle with an ably use of theroutes leading to the dialled destinations: Automatic Alternative Routing and Automatic Rerouting Route Switchover (Time Dependant Routing) Route Threshold Control Flexible Routing via PBX-Lines Optimized Dynamic Routing (ODR)

Routing and Network Management features concerning tunk groups and trunks: Trunk Group Cluster and Proportional Bidding Network Management Controls (NMC) Selective Circuit Reservation (SCR) Automatic Congestion Control (ACC)

Further features like Network Traffic Management Center (NTMC) SS7 Overload Control for IN Traffic Quality of service control in the IP network Intelligent Networks Interception of Call Attemptscomplete EWSD routing functions for an optimized use of the available network re-sources.

16 A30828-X1178-G200-1-7618


3 Digit Translation

3.1 Determination of a DestinationThe dialing information leads to a code point (see Fig. 3.1), whereupon the traffic rout-ing procedure in the CP jumps to the address in the destination data table where thedestination belonging to the selected code point is stored (more than one code point canlead to the same destination, but not vice versa). Destinations are symbolic names fornetwork nodes to which outgoing calls can be routed (a destination may also be the sym-bolic name for an announcement). The network nodes can be local network nodes forterminating traffic or network nodes one level higher in the network hierarchy, leading tothe terminating network node.

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Fig. 3.1 Connection between calling and called subscriber

3.1.1 Digit Translation in LTG and CPDigit translation comprises the following activities: determining the number of digits to be collected preliminary digit translation in the line/trunk group (LTG) digit translation in the coordination processor (CP)

Transitnetwork

nodeH

Localnetwork

node1

Prefix for local network node 1 Prefix for local network node 2

The calling and called subscribers are located in different local areas(meshed network),the calling subscriber dials the prefix for local area 2 and the directory number

Transitnetwork

nodeM

The calling and called subscribers are located in the same local area(meshed network),the calling subscriber dials the directory number of the requested partywithout prefix

Localnetwork

node2

66000 77000

55000

Localnetwork

node2

Destination

Local net-work node1Local net-work node2

Transit-Netzknoten

Code-point

55

66

77

0

Localnetwork

node3

Localnetwork

node1

Transitnetwork

node

18 A30828-X1178-G200-1-7618


Fig. 3.2 Functional sequence in digit translation between LTG and CP

Determining the number of digits to be collectedIn digit translation, the digit-destination translator in the CP does not evaluate all of thedigits for the outgoing traffic, but only as many as are needed to identify the destinationoutside the own network node, so that a route can be selected.The additional digits needed for the exact identification of the called subscriber are eval-uated by the subsequent network nodes.

CPLTGDigit/dest.translator

Codepoint0997

09981

Dest.

z1

z2

Destinationdata table

CPLTG

1

Dialed informa-tion 55xyz

Digit translation

Message to CP

Command to GP

SET UP

SET UP

Dialed informa-tion 0997xxxx Message to CP

Command to GP

SET UP

COME AGAIN

09977

Dialed informa-tion 09876xxxx

Digit/dest.translator

Codepoint09876

098751

Dest.

z3

z4


Message to CP

Command to GP

DIGIT BLOCK

SET UP

09876 Message to CPDIGIT BLOCK

Message to GPSET UP

CPLTGDigit/dest. translator

Codepoint

55

DNblock

55xyz


2

3

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In the first example shown in Fig. 3.2, the digit-destination translator obtains code point55 from the dialed information 55xyz, and the directory number (DN) block 55xyz is ob-tained from the code point in terminating traffic.Whatever the signaling method, the number of message packets is the decisive timefactor, since each packet requires a protocol transaction. Because the calling subscriberdials the digits more slowly than they can be transmitted, an attempt is made here tocollect as many digits as possible close to the origin, to reduce the number of packets.Sometimes the system even waits until all of the digits are available before signaling isstarted.Trunk group data, digit translation data, destination data and routing data together de-termine whether and how many digits are collected in an network node.To allow for all possible permutations, the number of digits to be collected can be setanywhere in the range from 0 to 24 digits.The relevant decision criteria for end-of-selection determination are different for SS7,No.5 signaling and MFC-R2 signaling.Once the number of digits to be collected has been determined for each connection inaccordance with these criteria, the number of digits already received is compared in theCP with the total required number. If there are not enough digits, the CP uses theCOME AGAIN command to request additional digits from the LTG of the calling sub-scriber (see Fig. 3.2).In No.5 signaling, the request specifies the total number of digits required; in all othercases, the request specifies the difference between the number of digits required andthe number of digits received so far.More detailed information, together with administration hints and examples on the basicdigit translation functions in the CP is depicted in the operating manual under: Preliminary digit translation in the LTG Digit Translation in the CP Special Identifiers (Codes) Splitting and Merging Code Points Origin Dependant Routing Ambiguous code points with identical starting digits and different destinations

20 A30828-X1178-G200-1-7618


3.2 Traffic Restrictions and privileged Traffic

3.2.1 Traffic Restrictions due to Traffic TypesTraffic restrictions enable traffic to be blocked depending on both network node-specificdata and subscriber-individual data.Various types of traffic restriction can be created. Zone-dependent traffic restriction

Each zone can be assigned a zone-specific traffic type when the tariff database iscreated.Active traffic restriction classes are assigned to each subscriber, which can be mod-ified either only by the operator or also by means of subscriber control input. Theseare the same traffic restriction classes as those applying to destination-dependenttraffic restrictions. If the connections are zoned, a zone number is determined whencall-processing traffic is active. The associated traffic type is used, together with theactive traffic restriction classes of the calling subscriber, to access the zone-depen-dent traffic restriction table. This table contains the blocked combinations of trafficrestriction class and zone traffic type. If no traffic restriction is being applied, call set-up is continued; otherwise, the call is routed to an intercept.

Destination-dependent traffic restrictionEach destination is assigned a destination-specific traffic type for outgoing trafficwhen the database is created.Traffic types are created ( CR TRAT) and are assigned to a destination (i.e. to a codepoint, CR TRATCPT) .Active traffic restriction classes are assigned to each subscriber, which can be mod-ified either only by the operator or also by means of subscriber control input. Theseare the same traffic restriction classes as those applying to zone-dependent trafficrestrictions.When call-processing traffic is active, the traffic type of the selected destination isused, together with the active traffic restriction classes of the calling subscriber, toaccess the destination-dependent traffic restriction table. This table contains theblocked combinations of traffic restriction class and traffic type.If no traffic restriction is being applied, call setup is continued; otherwise, the call isrouted to an intercept.

As soon as a destination-dependent or zone-dependent traffic restriction becomes ef-fective, the calling subscriber receives an advisory indicating the failure of the call at-tempt. The system response can be administered for each traffic type and for the tollcatastrophe traffic restriction. For this purpose, an intercept is specified for each traffictype. It is usually predefined specifically for the traffic type, but can be modified.

3.2.2 Privileged TrafficThe feature Privileged Traffic allows certain subscriber categories and certain callednumbers to be given priority treatment in the routing process. The feature comes intoeffect when congestion occurs as a result of sudden emergencies such as natural disas-ters, major fires, multiple car crashes etc. The feature ensures that privileged subscrib-ers are still able to make outgoing calls in the network and that facilities such as police,fire department and ambulance can be reached.The feature Privileged Traffic permits priority handling of: Traffic from privileged subscribers

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Traffic to privileged directory numbers

Operator benefits traffic from privileged subscribers and to certain directory numbers is upheld in

emergency situations that cause network congestion compliance with official requirements prevention of network overload

Subscriber benefits privileged subscribers can continue to make outgoing calls emergency numbers can be reached at all times

3.2.2.1 Traffic from privileged subscribersPrivileged subscribers are assigned a special subscriber category. In the event of anemergency resulting in network congestion, EWSD can support outgoing calls from priv-ileged subscribers with the following measures: Selective Circuit Reservation (Trunk Reservation) Trunk queuing Seizure repetition (pumping) Privileged connection

Selective Circuit Reservation (Trunk Reservation)Selective Circuit Reservation (also known as Trunk Reservation) allows a network op-erator to give priority to certain types of traffic on selected trunk groups. A number oftrunks in the trunk group are reserved for privileged traffic. For a more detailed descrip-

EWSDnetwork nodein "privileged"

state

emergencycenter

busy tone

privilegedsubscriber

normalsubscribers

all subscribers

22 A30828-X1178-G200-1-7618


tion and adminitration hints ref. to section 6.6 "Selective Circuit Reservation (SCR)" inthis manual.

Trunk queuingTrunk queuing has the effect that a connection is not released if a privileged subscribercalls a busy number or if all trunks leading to the dialed destination are busy. The privi-leged subscriber is put in a queue for 40 seconds and hears an announcement. Duringthis time, EWSD monitors the dialed number to find out whether the existing call hasbeen terminated or whether a trunk leading to the dialed destination has become free.If the called subscriber or a trunk is free again after this time, the connection is set up.Otherwise the connection is released and the privileged subscriber hears busy tone.

Fig. 3.3 Trunk queuing

Seizure repetition (pumping)With seizure repetition (pumping) (see Fig. 3.4), an unsuccessful call setup by a privi-leged subscriber is repeated under the following conditions: all available trunks are busy, but in theory there must be at least one trunk that can

be used for the whole destination range all overflow options are exhausted call setup leads to an emergency areaSeizure repetition is usually performed for a period of 30 seconds with an interval of 2seconds. However, these times can be set as required.

EWSDnetwork node

all trunks busy

normalsubscribers


announcement sentfor up to 40 s,until a trunk is free

busy tone

or

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Seizure repetition does not occur if all routes/trunk groups or trunks are blocked if there is signaling overload for the last trunk group or route, in the case of SS7 sig-

naling the seizure attempt was made by an operator

Fig. 3.4 Seizure repetition

Privileged connectionPrivileged connection becomes effective for new connections only after the networknode has been switched to "privileged" and only when no more free trunks are available.If an EWSD network node is in the "privileged" state, existing connections can be forciblyreleased if a privileged subscriber is trying to make a call and no free trunks are avail-able. An existing connection cannot be forcibly released if it is a privileged connection.

EWSDnetwork node

all trunks busy


seizurerepetition:until a trunk isfree, max. 30 s

24 A30828-X1178-G200-1-7618


Fig. 3.5 Privileged connection

The privileged label is assigned to a subscriber on connection setup per connection,regardless of the privileged state of the EWSD network node.The authorization of the A-subscriber is always the deciding factor in identifying a con-nection as "privileged". If a number of independent connections are linked together bysubscriber service features, then for each individual connection the "privileged" charac-teristic of the originating subscriber always applies.If, in outgoing traffic in a "privileged" EWSD network node, there are no longer any freespeech channels available between DLU and LTG or between LTG and SN and on thesubsequent connection paths, a speech channel is assigned to a subscriber identifiedas "privileged" for connection setup. This is done by releasing an existing connection notprotected by "privileged", without prior warning to the subscriber concerned. All trunksbusy is sent to the subscriber at the other end of the cleared connection as the reasonfor release.Connections identified as "privileged" are given priority as long as connections exist thatare not protected by being "privileged". If all connections are already marked as "privi-leged", even a subscriber with the "privileged" label cannot be assigned a path for set-ting up a new connection.In incoming traffic, in a "privileged" EWSD network node, connections identified as"privileged" take priority over connections not identified as "privileged" or connectionsidentified as "privileged" but not protected against release. Priority handling only takeseffect if the dialed subscriber is free. If the dialed subscriber is busy the connection isreleased with subscriber busy unless other features (e.g. call waiting, call forwardingetc.) are activated. If the dialed subscriber has the attribute "privileged", this has no ef-fect.The "privileged" state always applies to the entire network node.

normal sub-scribers


cannot makeoutgoing callsif the networknode is in the"privileged" state

EWSDnetwork nodein "privileged"

state

busy tone

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Priority handling of a connection affects the entire connection path. The "privileged" la-bel is passed on to all network nodes involved.Control of the "privileged" state in a transit network node corresponds to the control in asubscriber network node.Privileged connections are also described in the feature description Preference Catego-ry During Catastrophe.

Traffic to privileged directory numbersThe Emergency Call Service feature (see Fig. 3.6) allows a subscriber to set up an(emergency) call to an emergency center (fire, police, ambulance). By dialing a generalemergency number the subscriber reaches the closest emergency service center (in ac-cordance with ETSI 9.1).The system can replace the number dialed by the subscriber by defined directory num-bers consisting of up to ten digits.Each subscriber is assigned to an emergency area. The general emergency numbersare replaced in accordance with their identification by the directory numbers belongingto the relevant emergency area. Any number can be assigned as a general emergencynumber. The emergency destinations can be in the local area and in the national toll traf-fic area.This feature applies to all the subscribers of an EWSD network node.If required by the network operator, traffic restrictions and blocking of a subscriber linecan be overriden by emergency calls.Emergency calls are handled like privileged connections, i.e. hunting for trunks and pathselection through the switching network are performed repeatedly.

Fig. 3.6 Emergency calls

3.2.2.2 Administration Hints and ExamplesThe operator can perform all administration functions on the EWSD NetManager (ENM)by means of user-friendly applications or MML commands.

EWSDnetwork

node privilegednumber

emergency ser-vice7012

emergency areas1 70...2 80...

26 A30828-X1178-G200-1-7618


Traffic Restrictions due to Traffic TypesFor information on the administration please refer to the corresponding section in theOMN:EXCH-RO/NT.

Selective Circuit Reservation (Trunk Reservation)For information on the administration please refer to the corresponding section in theOMN:EXCH-RO/NT.

Trunk QueingTrunk queuing is automatically initiated from the GP and needs no further MML admin-istration on the CP.

Seizure repetition (pumping)Seizure Repetition is automatically initiated from the GP and needs no further MML ad-ministration on the CP.

Privileged connectionThe administraion of Privileged connections is shown in the Feature Task ProcedurePCDC in the operating manual for subscriber administraion OMN:EXCH-SU.

Traffic to privileged directory numbersFor information on the administration please refer to the corresponding section Catas-trophe status in the OMN:EXCH-SY.The command for setting the "privileged" state (toll catastrophe) must be limited to auser group by definition of a separate command group as part of password administra-tion.

3.2.2.3 RequirementsNo additional hardware is needed.

3.2.2.4 Call charge registrationThe charges for originating traffic are recorded on the charge meter of the calling sub-scriber.The recording of charges for emergency calls can differ for each emergency call areadepending on the origin (e.g. non-chargeable emergency calls from public payphones).Emergency calls are treated as local calls or as non-chargeable calls (defined by the ad-ministration).

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3.3 Multiple Local Networks in One Network NodeThe feature Multiple Local Networks in one Network Node allows subscribers fromup to 4095 different local networks to be connected to one network node via remote dig-ital line units (DLU). This means, for example, that subscribers belonging to a region withanalog network nodes can be provided with ISDN services on a economical basis. Suchsubscribers are then switched physically to the remote ISDN-capable network node. Atthe same time, however, they are still members of their local network area.It only makes sense to have more than 50 local networks per exchange when relativelyfew subscribers are to be connected per local network. It is possible for parts of one ormore local networks to be administrated from the local exchange, while the other parts(of these local networks) are connected to distant exchanges (see section 3.3.1 "Modeof operation").

Fig. 3.7 Multiple Local Networks in One Network Node

Operator benefits For an established operator

Separate network nodes are not necessary for small local networks.Subscribers belonging to such networks can be connected to distant DLUs whichare then routed to a network node.

For an alternative operatorFor a small number of subscribers scattered over a large number of local networks,it is sufficient have just one or a few network nodes to connect all this operators sub-scribers.

EWSD

Local net-work4095

Local net-work

1

DLU

DLU

28 A30828-X1178-G200-1-7618


3.3.1 Mode of operationThe feature Multiple Local Networks in One Network Node is available in the follow-ing variants (see Fig. 3.8): Variant 1:

Several complete local networks in one network node. Variant 2:

A complete local network and part of a local network in one common network node(one local network distributed over several network nodes).

Variant 3:Parts of several local networks in several network nodes(several local networks distributed over several network nodes).

Variant 1 can be used wherever a concentration of several local networks in one com-mon network node seems geographically expedient.One application for Variant 2 and possibly also for Variant 3 is the connection of sub-scribers to a distant network node which has ISDN capability (overlay mode). In this waythe ISDN service can be made available to subscribers in an analog network environ-ment. The ISDN subscribers connected from outside keep the local area code of the an-alog network node to which they belong geographically. Overlay mode allows ISDN tobe introduced in stages in a network (see Fig. 3.12).

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Fig. 3.8 Variants of the feature Multiple Local Networks in One Network Node

Networknode

A

Localnetwork

1

Variant 1:

Variant 2:

Networknode

B

Variant 3:

Localnetwork

2

Localnetwork

1

Localnetwork

2

Localnetwork

2

Networknode

A

Networknode

A

Localnetwork

1

Localnetwork

2

Localnetwork

2

Networknode

B

DLU

DLU

DLU

DLU

DLU

DLU

DLU

DLU

DLU

Localnetwork

1

30 A30828-X1178-G200-1-7618


Connection setup with variant 1

Fig. 3.9 Example for variant 1: Multiple Local Networks in One Network Nodein the case of a multiple directory number volume

Subscriber A subscriber B (subscriber A dials 4712 or prefix A + 4712)Subscriber A subscriber C (subscriber A dials prefix B + 4711)Subscriber B subscriber C (subscriber B dials prefix B + 4711)Subscriber B subscriber A (subscriber B dials 4711 or prefix A + 4711)Subscriber C subscriber A (subscriber C dials prefix A + 4711)Subscriber C subscriber B (subscriber C dials prefix A + 4712)

Networknode

A

B

C

Local net-work

A

4711

DLULocal net-work

B

4712

4711DLU

A30828-X1178-G200-1-7618 31

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Connection setup with variant 2 and variant 3

Fig. 3.10 Example for variant 2 and possibly variant 3

Subscriber A subscriber B (subscriber A dials prefix C + 4711)Subscriber A subscriber C (subscriber A dials prefix C + 4712)Subscriber B subscriber A (subscriber B dials prefix A + 4711)

3.3.1.1 Numbering and directory number volumeWhen several complete local networks are connected to one network node (variant 1)there are two categories of local area codes: independent local area codes e.g. 089 and 088 local area codes derived from each other e.g. 089 and 0898 and 08989In variants 2 and 3 the directory number volume of one local network and parts of sev-eral local networks has to be administrated at one network node.The administration must make sure that the directory number volume is unique, i.e. thata directory number (consisting of local area code and subscriber directory number) onlyoccurs once in all local networks of the network node and in the network as a whole. Adistinction is therefore made between being unique in a country, unique in a local net-work and unique in a network node.

Networknode

A

Localnetwork

C

Localnetwork

A

Networknode

B

4712outgoing traf-fic

Localnetwork

C

DLU

4711

4711

4712

DLU

DLU

A

B

C

32 A30828-X1178-G200-1-7618


To guarantee the directory number volume, EWSD provides the following aids and pro-cedures: Directory number attribute (unique or multiple) Directory numbers with local area codes containing partly identical digit sequences

when several local networks are connected to one network node

Directory number attribute (unique or multiple)A directory number attribute (parameter in the MML command) can be used to specifywhether the directory number volume for a network node with several local networks isto be unique or multiple.If it is to be unique, each subscriber directory number may occur only once in a networknode with several local networks.If it is to be multiple, a subscriber number may occur several times in the network node,but may occur only once in each local network connected to the network node.Examples of two independent local area codes in a network node with: unique directory number volume

multiple directory number volume

Directory numbers with local area codes containing partly identical digit sequenc-es when several local networks are connected to one network nodeThis case occurs when two or more complete local networks are derived (split off) fromone local network. The subscribers belonging to the original local network can keep theirdirectory numbers.The local networks that are split off can be connected to the own network node or other

Local area code Directory numbers089 4711 (PBX block)

47120 ...... 47129 (10s block)471300 .... 471399 (100s block)4714000 .. 4714999 (1000s block)

088 4715 (PBX block)47160 ...... 47169 (10s block)471700 .... 471799 (100s block)4718000 .. 4718999 (1000s block)

Local area code Directory numbers089 4711 (PBX block)

47120 ...... 47129 (10s block)471300 .... 471399 (100s block)4714000 .. 4714999 (1000s block)

088 4711 (PBX block)47120 ...... 47129 (10s block)471300 .... 471399 (100s block)4714000 .. 4714999 (1000s block)

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network nodes, and they are given separate local area codes with a partly identical digitsequence (see example). Each local area code may only occur once in a communica-tion network, i.e. it must be guaranteed that the directory number volume for dialing thelocal networks from all the other local networks is unique. This referred to as a nation-ally significant directory number volume.Example for local area codes containing partly identical digit sequences when there areseveral local networks connected to one network node

To ensure that the directory number volume is unique after the splitting off, the follow-ing points must be taken into consideration:Each combination of local area code and subscriber number may only occur oncethroughout all local networks. In the example above this means that for the local areacode 089 there can be directory numbers beginning with 8, but code points for local areacode = 089 must differ in at least one digit from code points for local area code = 0898,i.e. 8790 in the local area with local area code 089, and 791 in the local area with localarea code 0898, are code points. For a new complete local network connected to an out-side network node, whose local area code has a partly identical digit sequence (e.g.089891), a code point must be created.

3.3.1.2 NumberingIn the numbering process a distinction is made between traffic in the same local networkand traffic between local networks.For connection setup the system evaluates: the local area code supplied or only the directory number of the called subscriber, if this subscriber belongs to the

same local network

Digit-destination area translatorIn EWSD, local area codes are evaluated in the digit-destination area translator like sub-scriber directory numbers. Local area codes for the own network node can be stored inthe translator.These local area codes are not needed when there is a uniquedirectory number volume. The codes cannot be dialed by the subscribers connected tothe network node.

Local area code Directory numbersbefore089 (one local network) 4711after089 old local network

(local network 1)4711 (previously) dir. no. with 8 allowed8790 = code point

0898 new local network(local network 2)

4711 (new)791 = code point

08989 new local network(local network 3)

4711 (new)

08989 new local network(outside network node)

4711 (new)new code point

34 A30828-X1178-G200-1-7618


In the case of a multiple subscriber directory number volume, however, (especiallywhen several local area codes with a partly identical digit sequence are connected tothe own network node), the local area codes are required. This ensures unambiguousnumbering in the own network node. The stored digit sequences are compared with thedialed digits. This initial comparison in the digit-destination area translator enables thelocal area code to be clearly identified.

Ability to dial own local area code in the network nodeAs regards subscribers ability to dial their own local area code in the network node, adistinction must be made between: calls to the own local network in the network node

(local area code assigned to a subscriber by the network operator) calls to another local network in the network node

(local area code of another local network connected to the network node)As a general rule subscribers in a network node can dial their own local area code forcalls within their own local network, but it is not necessary. The network operator alsohas the option of blocking local area codes for calls to the subscriber's own local networkand allowing them again.If the directory number attribute unique is assigned for the directory number volume,the local area code can be dialed for a call to the subscriber's own local network or toanother local network connected to the network node.If the directory number attribute multiple is assigned for the directory number volume,the local area code must be dialed for a call to another local network connected to thenetwork node.

Handling of emergency call areas in a network node with several local networksThe subscribers of all local networks of a network node can be assigned an emergencycall area according to their geographical location and depending on their originating lo-cal area code.Example (see Fig. 3.11):Local network A has emergency call area 1 assigned to it.Local network B has emergency call area 2 assigned to it.

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Fig. 3.11 Example of emergency call areas in a network node with several local net-works

Access to other carrier networksAppropriate code points have to be created for access to other carrier networks.

Access to the operator service system (ADMOSS)Appropriate code points also have to be created for access to the operator service sys-tem (ADMOSS) in an outside network node (outgoing traffic).Consequences for special test equipmentTest equipment for subscriber lines can often only process a limited number of digits ina directory number. In the case of a multiple directory number volume, the complete di-rectory number is necessary for unambiguous dialing of a subscriber line. The local areacode and the subscriber directory number may therefore exceed the maximum numberof digits that can be processed by the special test equipment.

3.3.1.3 Call charge registration

Digit-zone translation(Zoning dependent on originating local network)When a subscriber of one local network sets up a connection to a subscriber of anotherlocal network in the same network node, the subscriber charges may vary according tothe geographical location of the local networks.Example (see Fig. 3.12):Subscriber A in local network 1 dials local network 3, belonging to zone 2.Subscriber B in local network 2 dials local network 3, belonging to zone 1.Subscriber C in local network 3 dials local network 2, belonging to zone 1.

NetworknodeLocal

network A Emergencycall area 1

Local network BEmergencycall area 2

4711

A

4712

B

C

4711

DLU

DLU

36 A30828-X1178-G200-1-7618


Fig. 3.12 Zoning dependent on originating local network when there aremultiple local networks in one network node

The originating local area code (local network index of origin) is used for digit-zonetranslation just as it is for digit-destination area translation. This means that zoning canbe carried out for all the subscribers of a local network without individual origin codesbeing necessary.

3.3.2 RequirementsNo additional hardware is needed.

3.3.3 AdministrationThe operator can perform all administration functions on the NetManager by means ofuser-friendly applications or MML commands.For information on the administration please refer to OMN:EXCH-RO/NT.

NetworknodeLocal

network1

Localnetwork

2

Localnetwork

3

DLU

DLU

DLU

Zone

1Zo

ne1

Zone

2

A

B

C

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3.4 Routing via other CarriersThe feature Carrier Dependent Routing allows calls in deregulated networks to berouted via an alternative network operator (carrier). The subscriber selects the carrier bymeans of a carrier access code (CAC).For connections that are set up without dialing a carrier access code, up to two standardcarriers can be defined. The standard carriers can be selected according to destination(e.g. separate carriers for national and international connections).

The network nodes of a carrier have to distinguish between the following two types ofcalls during routing: Calls not intended for the carrier:

In these cases the CAC received does not match the carriers own CAC the carri-ers nodes need only switch the calls.

Calls intended for the carrier:In these cases the CAC received matches the carriers own CAC the carriersnodes have to perform one of the following functions for each of the calls:zoning, black/white list screening or Automatic Message Accounting (AMA).

Operator benefits additional revenue through service charges from subscribers who can select stan-

dard carriers service charges for traffic via other alternative carriers

Subscriber benefits subscribers can choose between two standard carriers offering the best conditions further alternative carriers are available

3.4.1 Mode of operationFor call setup in networks with several carriers, the following different functions areavailable: Routing when a carrier access code is dialed Routing when no carrier access code is dialed Routing via several carrier networks

EWSD

standard carrier 2dialed carrier 3dialed carrier 5

dialed carrier 4

standard carrier 1dialed carrier 3

directory number (national / international)carrier access code + directory number

destination Ae.g.

national

destination Be.g.

international

38 A30828-X1178-G200-1-7618


Routing when a carrier access code is dialedThe subscriber usually selects the desired carrier explicitly by dialing the carrier accesscode.Depending on the carrier, the carrier access code can additionally be split up into a car-rier prefix (one to three digits, valid for the entire network) and the actual carrier accesscode. This means that the codes for all carriers in the network can begin with the samedigit stem.Example:

Depending on the signaling method used, the carrier access code can be transportedeither as the first part of the B-directory number or, in networks with signaling systemNo.7 (SS7), in a separate data field of the ISUP message (initial access message IAM).To administrate carrier prefixes, use the ENTR DNATT command together with param-eter PFXCAC (see OMN:EXCH-SU).

Fig. 3.13 Routing when a carrier access code is dialed

national carrier with prefix = 0100102301040

local net-work

1

A

localnetwork 2(national /

international)

dialedcarrier

B

localnetwork

node

gate-way net-

worknode

gate-way net-

worknode

localnetwork

node

gate-way net-

worknode

A30828-X1178-G200-1-7618 39

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Routing when no carrier access code is dialedWhen a connection is set up without dialing a carrier access code, a distinction is madebetween: routing via a standard carrier, individual

If a subscriber dials a destination that is preferably reached via a carrier but does notdial a carrier access code, routing first uses the subscribers standard carrier if sucha carrier has been created.

routing via a standard carrier, network nodeIf the subscriber has no standard carrier, routing attempts to reach the destinationvia the standard carrier created for the network node.

standard routingIf no standard carrier has been created in the network node, routing attempts toreach the destination without a carrier access code (standard routing). However, thiscan only be done if the database has been set up appropriately.

If the standard carrier access code of the subscriber or the network node is the carrieraccess code of the own network, it is ignored for routing, and standard routing withouta carrier access code is performed. Alternatively, an announcement can be applied ask-ing the subscriber to dial the destination with a carrier access code.Standard carriers can be assigned individually to subscribers, PBXs, PBX lines, trunkgroups, CENTREX groups and CENTREX stations.The carrier can additionally define two standard carriers for the entire network node.With the appropriate authorization, subscribers can assign themselves these standardcarriers for different destinations (e.g. national local area/long-distance area or national/international), by means of subscriber controlled input.If the subscriber has dialed a carrier, or if a standard carrier is used for routing, there isnot normally any overflow to another carrier.

40 A30828-X1178-G200-1-7618


Fig. 3.14 Routing when no carrier access code is dialed

Example of routing via several carriersThe gateway network nodes form the boundary to other carriers. This means that thecarrier can assign a gateway functionality to specific trunk groups. By removing the ownaccess code it is possible to select a remote carrier. However, the carrier access codeof the remote carrier must be available for routing in the carrier network, i.e. in a gate-way network node a carrier access code may only be removed from the dialing informa-tion if it is the own carrier access code.With the help of the network configuration shown in Fig. 3.15, the following example de-scribes two route variants. Variant 1 shows how the A-subscriber, by dialing a particularnumber, determines the B-subscriber via a desired carrier. Variant 2 shows how a car-rier is determined by the network:

local net-work

1

A

localnetwork 2 (na-

tional/international)

standardcarrier

individual /network node

B

localnet-worknode

localnet-worknode

gate-way net-

worknode

standard routing

gate-way net-

worknode

gate-way net-

worknode

A30828-X1178-G200-1-7618 41

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Fig. 3.15 Routing via several carrier networks

Variant 1:If an A-subscriber in local network 1 dials the CAC = 09555 to reach a B-subscriber viacarrier network 1, the call is routed to the gateway of carrier 1. In the gateway (incom-ing), the callers CAC 09555 (OWNCAC) is removed. Thus a new CAC can be definedin carrier 1 (via one of the two exchanges preferred carriers or one of the two preferredcarriers in the trunk group), or hunting can take place according to previous routing.Assuming that on the basis of the converted B number in carrier network 1, a CAC (e.g.:CAC = 09888) has recently been defined for carrier 4, this has to be transported fromgateway 1 (incoming) by the local network. In this way, the original information on the A-subscriber carrier selection, which may be relevant for AMA tickets, is lost.

carrier 1CAC=09555

local network 2CAC=OWNCAC=

09111

B

gatewaynetwork

node

gatewaynetwork

node

carrier 2CAC=09777

carrier 3CAC=09999

carrier 4CAC=09888

gatewaynetwork

node

gatewaynetwork

node

gate-waynet-worknode

gate-waynet-worknode

localnet-worknode09222

A

localnet-worknode

local network 1CAC=OWNCAC=

09222

42 A30828-X1178-G200-1-7618


At the gateway of carrier 4, the local CAC is removed. Digit translation supplies the in-formation that no further carrier is required since network 2 can be directly addressedby carrier 4.

Variant 2If the A-subscriber in local network 1 dials the CAC = 09222 to reach local network 2,the call is then routed to the gateway exchange of carrier network 1 or 3. The incominggateway notices that the received CAC is different from its own CAC. Therefore the re-ceived CAC remains unchanged and is used for further routing.Since the CAC addresses destination network 2 and contains no information about theroute to be used, either carrier 2 or carrier 4 can be used in the next step to reach thedestination network.

3.4.2 Charge registrationThe AMA ticket only specifies the carrier actually used by the routing. Billing betweenthe individual carriers is done by means of inter-administrative traffic data recording.Charging for feature input is based on the current carrier access code value.No charge can be made for feature usage.


3.4.4 AdministrationThe operator can perform all administration functions on the NetManager by means ofuser-friendly applications or MML commands.Administration hints and examples on routing via other carriers are depicted in theOMN:EXCH-RO/NT.

i In deregulated networks, local exchange call handling for long-distance calls ends in agateway exchange. For this reason, there may be no information on the actual destina-tion.

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3.5 Traffic Control with the Carrier Access CodeSubscribers in a multi-carrier environment can decide themselves which carrier is to beused for routing for a call.Using the Traffic Control with the Carrier Access Code feature, a carrier can dis-tinguish the traffic to be switched from a specific network node from the traffic to bezoned by the node.In the latter case the traffic is identified by analyzing the carrier access code (CAC) sentby the subscriber.If the CAC received in a network node matches the nodes own CAC, the following func-tions can be initiated: Zoning Black/white list screening Automatic Message Accounting (AMA)

Benefits for the carrier The expensive, error-prone trunk splitting method is replaced. The administrative work is reduced. Hardware investment costs are reduced.

calledparty

callingparty

Net-worknode

1

Carrier 1

Net-worknode

2

Carrier 2

Net-worknode

3

Carrier 3

CAC = Carrier 2

ZoningBlack/white list screeningAMA ticket generation

TNS

CAC Carrier 2

Switching

44 A30828-X1178-G200-1-7618


3.5.1 Mode of OperationEvery carrier in a multi-carrier environment is assigned a carrier access code (CAC). Us-ing the CAC, a subscriber can select a particular carrier for individual calls (call-by-call)or permanently assign a particular carrier. The CAC is transferred between the networknodes as part of the directory number or as a separate parameter in the ISUP message.The network nodes of a carrier have to distinguish between the following two types ofcalls during routing: Calls not intended for the carrier:

In these cases the CAC received does not match the carriers own CAC the carri-ers nodes need only switch the calls.

Calls intended for the carrier:In these cases the CAC received matches the carriers own CAC the carriersnodes have to perform one of the following functions for each of the calls:zoning, black/white list screening or Automatic Message Accounting (AMA).

3.5.1.1 ZoningSubscribers can determine which carrier has to perform the call routing resulting in zon-ing. For specific projects carrier to be used for billing can be directly defined.The implementation of the feature requires the introduction of the following three newparameters/parameter values: the national ISUP parameter CONZON

This forwards a message indicating that the call was zoned. the APS parameter IK_RTRUS

The signaling and analysis of the national parameter CONZON is not permitted ifthis parameter is not set.

UNCZON of the GCOS parameter (flag in the incoming trunk group)This value is used for forced zoning so as to have an opportunity to perform the zon-ing without consideration of the signaled information.

CONZON indicates to subsequent network nodes whether a call is already zoned or not.The parameter is only transmitted and analyzed once the corresponding function hasbeen specially activated in the network node.The indication call zoned is activated by the network node that defines the charges (Charge Determination Point, CDP) if

the relevant zone applies. by any network node receiving the call over a special NOZON trunk (trunk group).

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Analyzing the carrier access code (CAC)The carrier access code and the CONZON parameter are analyzed to determine wheth-er zoning is required for a call.Zoning is implemented if the GCOS parameter value ZON is set and the ISUP param-eter CONZON is not set (zoning indicator = FALSE), and if one of the following condi-tions is satisfied: the received CAC matches the carriers own CAC no CAC was received in the TNS parameter

Fig. 3.16 Zoning

Fig. 3.16 shows the following functional sequence:A subscriber in the network of carrier 1 sets up a call to a subscriber in the network ofcarrier 3.The calling party dials the CAC of carrier 2 so that this carrier performs the billing. TheTNS parameter in the ISUP message therefore contains the CAC of carrier 2. In the network of carrier 1

In the carrier 1 network the call is routed in the direction of the network of carrier 2.No zoning is performed (zoning result is ZONINH, the CONZON parameter has Zon-ing Indicator = FALSE).

In the network of carrier 2The parameter value ZON is set in the gateway of the carrier 2 network. The call tobe set up recognizes from the CONZON parameter that zoning has not yet occurred(zoning indicator = FALSE in the CONZON parameter). The gateway node then an-alyzes the CAC transferred in the TNS parameter of the ISUP message. The gate-way determines in this way whether the charges for the call are recorded in its ownnetwork. The received CAC matches the carriers own CAC in the example shownin Fig. 3.16 i.e. zoning is performed. The zoning result is a valid zone. TheCONZON parameter informs the subsequent networks involved in the call that thecall has already been zoned (Zoning Indicator=TRUE).

calledparty

callingparty

Net-worknode

1

Carrier 1

Net-worknode

2

Carrier 2

Net-worknode

3

Carrier 3

CAC = Carrier 2Selection ofcarrier 2for routing / bill-ing

CONZON CONZON

ZON

46 A30828-X1178-G200-1-7618


In the network of carrier 3Zoning is likewise not performed in the gateway node of the carrier 3 network be-cause the CONZON parameter indicates that the call has already been zoned in thenetwork of the previous carrier.The CONZON parameter is routed in the carrier 3 network to the destination networknode, to which the called subscriber is connected.

There are two exceptions in which no CAC digits are sent with the TNS parameterthrough the network. They are as follows: End traffic

In this case the calling party dials only the number of the destination party no par-ticular carrier is specified. If the destination party belongs to a different carrier net-work, the call is routed to the appropriate gateway and from there to the called party.

Service providersIf a subscriber requests a service provided by a particular carrier, the call is routedto that carriers network although no CAC digits were dialed.

3.5.1.2 Black/White List ScreeningAnalysis of the CAC also indicates whether black/white list screening is to be performedin a carriers network.Black/white list screening is performed in the following cases: if the CAC received matches the carriers own CAC if black/white list screening is activated in the network node

Fig. 3.17 Black/white list screening

The GCOS-parameter value for carrier access code screening (CR TGRP: ...,GCOS =CACSCR) is set in the network node of carrier 2. (see Fig. 3.17). The call to be set rec-ognizes from the CONZON parameter that no zoning has yet occurred (CONZON pa-rameter with Zoning Indicator = FALSE). The gateway node therefore performsblack/white list screening. The CONZON parameter is used to inform the subsequentnetwork nodes that black/white list screening has been carried out.

i If the parameter value UNCZON is set for the incoming trunk group at the CDP of thecarrier 3 network, the incoming call is zoned regardless of the set zoning indicator thatwas received in the CONZON parameter; a CONZON parameter is generated with anew zoning indicator and transferred.

calledparty

callingparty

Net-worknode

1

Carrier 1

Net-worknode

2

Carrier 2

Net-worknode

3

Carrier 3

CAC = Carrier 2CACSCR

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3.5.1.3 AMA Ticket GenerationThe functions described in Section 3.5.1.1 for zoning are also used here. This meansthat the TNS parameter has to be signaled beyond the network boundaries.The following functional sequence applies whenever an AMA ticket is requested (indi-cated by setting of the parameter value AMAREQD) and the zoning result is available.

Fig. 3.18 AMA ticket generation

AMA tickets are generated in the following cases (see Fig. 3.5.1.3): If the CAC of the dialed carrier matches the signaled CAC, the carrier zones the call.

AMA tickets are generated if the zoning parameter indicates BILLING=AMA. If the parameter value AMAREQD is set for the incoming trunk group, AMA tickets

are always generated (regardless of TNS, CONZON, zoning, etc.).

3.5.2 RequirementsNo additional hardware is required.

3.5.3 AdministrationFor information regarding administration of the feature, refer to the OMN:EXCH-RO/NTand OMN:EXCH-TA.The operator can perform all administrative functions on the NetManager.User-friendly applications or MML commands can be used for the administration.

calledparty

callingparty

Net-worknode

1

Carrier 1

Net-worknode

2

Carrier 2

Net-worknode

3

Carrier 3

CAC = Carrier 2

CONZON

AMAREQD

48 A30828-X1178-G200-1-7618


3.6 Customer-Dependent RoutingThe feature Customer Dependent Routing allows calls to be routed via selected car-riers or selected trunk groups offering better transmission quality, for instance. This typeof routing can be provided for customers of one particular network operator (e.g. largecompanies), or for other operators in the network. The customers or network operatorsare given customer numbers, and these customer numbers (CUSTID) are assigned tothe corresponding subscribers, PBX line groups (see OMN:EXCH-SU) and incomingtrunk groups. Connections with special routing can then be identified by means of thecustomer number.The feature Customer Dependent Routing can be used in gateway network nodes andalso in local networks.

Operator benefits easy administration for individual routing, using customer numbers additional revenue due to customer- or operator-dependent routing

3.6.1 Mode of operationThe feature Customer Dependent Routing is available in two variants: customer-dependent routing (see Fig. 3.19) operator-dependent routing (see Fig. 3.20)The functional sequence of the features is as follows: A customer or a network operator with individual routing is identified by means of the

customer number in the subscriber data (COSDAT=CUSTROUT) or in the data ofan incoming/bothway (IC/BW) trunk group (GCOS=CUSTROUT) .

An ISUP message then transmits the customer number, the identifier for customer-dependent routing, and, if applicable, a flag for code blocking suppression, to a na-tional/international gateway network node where the customer number can be iden-tified and customer-dependent routing can be performed.

callingsubscriber

Gatewaynetwork

node

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standard route

via selectedcarrier

Networknode

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A flag in the ISUP protocol can be used to distinguish between individual routing fornational calls and individual routing for international calls.

For customers who are to be identified via an incoming/bothway (IC/BW) trunk group, acode in the trunk group GCOS=SUPCBLK) can be used to deactivate a code block in atransit or gateway network node.Code blocking can be also deactivated for calls from specific national networks (e.g. mo-bile radio networks), these being treated as customers in this case.

Fig. 3.19 Customer-dependent routing

tointernational ornational carrier

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Customer A

name:customer no.:

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Fig. 3.20 Operator-dependent routing

CapacityUp to 999 customer numbers can be allocated.Each customer number can be assigned up to 150 destinations.

Interaction with other featuresThe feature Customer Dependent Routing in gateway network nodes has no effect onproportional bidding and dynamic routing. These procedures only involve calls on onetrunk group cluster or the carrier selection destinations of one quota group.


3.6.3 AdministrationThe operator can perform all administration functions on the NetManager by means ofuser-friendly applications or MML commands.For information on the administration please refer to OMN:EXCH-RO/NT.

EWSDNetworkoperator

tointernational ornational carrier

Localnetwork

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Localnetwork

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name:customer no.:

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3.7 Local Number Portability (LNP, IN method)The feature Number Portability allows subscribers to keep their directory number whenthey move within the same local area or change to another network operator.If a subscriber in a particular local network moves from the area of one EWSD networknode to the area of a different EWSD network node, without changing to another net-work operator, this is called geographical portability.If a subscriber changes to another network operator within one and the same local net-work, this is called operator portability.

Operator benefits solution integrated in EWSD, no additional hardware dynamic operation due to data storage in EWSD network nodes directory number portability for SCCP signaling without any effect on protocols and

applications same database for ISUP and SCCP routing (no cross-checks) EWSD offers security in terms of reliability and fail-safe performance separation of ported data and static global title translation (GTT) data no new OA&M interfaces

Subscriber benefits the directory number is independent of the location subscribers no longer have to notify people of a new telephone number when mov-

ing within the local network

EWSDnetwork

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Operator A

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3.7.1 Mode of operationTo set up a connection to a ported subscriber, the system must have up-to-date infor-mation about the subscribers location. This information is kept centrally in one EWSDnetwork node for the entire local network or for a local network area. For this purposethe EWSD network node has an extended database function for local number portability(LNP).Number portability is possible in EWSD for bearer-related calls bearer-unrelated callsIn the case of bearer-related calls, access to the LNP database is as follows (Fig. 3.21) EWSD network nodes via SS7 (ISUP) external (non-EWSD) network nodes via IN application (INAP)For bearer-related calls, the LNP database is accessed if the digit analysis in the originating network node indicates a ported subscriber (Que-

ry on digit analysis method, QoD) the called subscriber is unknown in the destination network node

(Query on release method, QoR)In the case of bearer-unrelated calls, the signaling connection control part (SCCP) ac-cesses the LNP database (ref. OMN:EXCH-SS7).

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Fig. 3.21 Options for accessing the regional LNP database

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RegionalLNP

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Documents

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