Contents

1   Introduction

This document describes how to configure the Trunk Group service in MTAS.

1.1   Prerequisites

It is assumed that the user of this document is familiar with the O&M area, in general.

1.1.1   Documents

Before starting any procedure in this document, ensure that the following document is available:

• Managed Object Model (MOM)

2   Overview

The Trunk Group service of the MMTel AS emulates an originating PSTN Gateway (RFC4904) providing trunk group information to be used in IMS core routing, based on either the dialed number, call type or if the call is voicemail.

The Trunk Group service is applicable to originating calls of wireline subscribers (including terminating diversions). It adds configured tgrp and trunk-context parameters to the Contact header of the outgoing INVITE. The values of the parameters are primarily determined by if the call is a voicemail retrieval or deposit, secondary from B-Number type and ultimately from call type.

Trunk Group information added by the MMTel AS to the Contact header in the downstream direction, is removed from in-dialog SIP requests sent upstream.

2.1   Subfunctions

2.1.1   Adding tgrp and trunk-context Based on Voicemail Retrieval or Deposit

The MMTel AS first checks if the ongoing call is a voicemail retrieval or deposit, and if the Trunk Group function is configured, see Section 3 Trunk Group Service Configurations, to be triggered by that. If both are fulfilled, the tgrp and trunk-context parameters are added to the Contact header of outgoing INVITE.

2.1.2   Adding tgrp and trunk-context Based on B-Number Type

If the preconditions in Section 2.1.1 Adding tgrp and trunk-context Based on Voicemail Retrieval or Deposit are not met, the MMTel AS checks if there is a B-Number classification and if the Trunk Group function is configured, see Section 3 Trunk Group Service Configurations, to be triggered by that. If both are fulfilled, the tgrp and trunk-context parameters are added to the Contact header of outgoing INVITE.

2.1.3   Adding tgrp and trunk-context Based on Call Type

If the preconditions in Section 2.1.2 Adding tgrp and trunk-context Based on B-Number Type are not met, MMTel AS checks if there is a call type classification and if the Trunk Group function is configured, see Section 3 Trunk Group Service Configurations, to be triggered by that. If both are fulfilled, the tgrp and trunk-context parameters are added to the Contact header of outgoing INVITE.

3   Trunk Group Service Configurations

The Trunk Group service is controlled by the MtasTrunkGroup Managed Object Class (MOC).

The Managed Object (MO) structure of the MtasTrunkGroup service is shown in Figure 1.

For configurable MOs and attributes related to general Trunk Group service configuration, refer to Managed Object Model (MOM).

3.1   Voicemail

To configure addition of tgrp and trunk-context based for voicemail retrieval or deposit, the attribute mtasTrunkGroupForVoiceMailRetrievalOrDeposit must be set to TRUE. The Contact header gets populated with the tgrp value defined by the mtasTrunkGroupForVoiceMailTrunkGroup attribute and trunk-context is defined by the mtasTrunkGroupForVoiceMailTrunkContext attribute, respectively.

3.2   B-Number Type

Entries keyed on B-Number type can be added to the attribute MtasBNumberTypeList. If there are no tgrp and trunk-context additions based on voicemail, but there is a B-Number type classification for the call and a matching entry in MtasBNumberTypeList, then the Contact header gets populated with the tgrp value defined by the mtasBNumberTypeTrunkGroup attribute and trunk-context is defined by the mtasBNumberTypeTrunkContext attribute, respectively, of the matching entry.

For supported B-Number types, see MTAS Number Translation Management Guide.

3.3   Call Type

Entries keyed on call type can be added to the attribute MtasCallTypeList. If there are no tgrp or trunk-context additions based on B-Number type, but the number analysis function has a call type defined and there is a matching entry in MtasCallTypeList, then the Contact header gets populated with the tgrp value defined by the mtasCallTypeTrunkGroup attribute and trunk-context is defined by the mtasCallTypeTrunkContext attribute, respectively, of the matching entry.

Supported call types are:

• Local
• Non-Local
• IntraLata
• IntraLata Toll
• InterLata
• InterLataLocal
• International
• National
• NanpZone1

4   Performance Management

MTAS does not create any statistics for Trunk Group service invocations.

5   Fault Management

There are no alarms related to the Trunk Group service.