After upgrading to Exchange Unified Messaging (UM) 2010 SP1, using the UM Auto Attendant for call transfers may fail for Office Communications Server 2007 R2 dial plans. This article tells you how to resolve this issue.

Author: Jigar Dani

Publication date: February 2011

Product version: Microsoft Office Communications Server 2007 R2

With Microsoft Exchange Unified Messaging 2010 SP1, the call transfer to a phone extension has improved by allowing Communications Server to decide how to route the call.

Prior to Exchange UM 2010 SP1, Exchange UM sent the location profile that Communications Server must use to transfer a call to an extension. This was indicated in the Refer-To header in the REFER (the message used to transfer the call to the extension).

REFER sip:alice@contoso.com SIP/2.0

Via: SIP/2.0/UDP test.contoso.com;branch=z9hG4bK2293940223

To: <sip:alice@test.contoso.com>

From: <sip: amit@test.contoso.com >;tag=193402342

Call-ID: 898234234@ test.contoso.com

CSeq: 123 REFER

Max-Forwards: 70

Refer-To: clark@test.contoso.com;phone-context=test.contoso.com

Contact: sip:amit@test.contoso.com

Content-Length: 0


The phone-context parameter in the Refer-To header indicates the location profile that Communications Server should use. This information came from the UM dial plan. The UM dial plan must have exactly the same name as the Communications Server location profile. For details about this, see page 441 of the Office Communication Server 2007 R2 Resource Kit.

With Exchange UM 2010 SP1, the location profile information is no longer relayed. In the Refer-To header, you will now see the following:

REFER sip:alice@contoso.com SIP/2.0

Via: SIP/2.0/UDP test.contoso.com;branch=z9hG4bK2293940223

To: <sip:alice@test.contoso.com>

From: <sip: amit@test.contoso.com >;tag=193402342

Call-ID: 898234234@ test.contoso.com

CSeq: 123 REFER

Max-Forwards: 70

Refer-To: clark@test.contoso.com;phone-context=user-default

Contact: sip:amit@test.contoso.com

Content-Length: 0

The Refer-To indicates that Communications Server is to use the default location profile. This is how Exchange UM enables Communications Server to select the best location profile to use. This requires that a default location profile be configured in Communications Server.

When troubleshooting this scenario, the following symptoms might indicate that the location profile was not selected:

  • Exchange UM 2010 SP1 dial-by-extension does not work for the Communications Server dial plan.
  • Call transfer via key mappings in UM Auto Attendant to extensions, such as an operator, do not work.

Both of these transfer the call to an extension in Communications Server. Without a default location profile in place, Communications Server does not know how to route the call to this extension.

However, if users use the directory lookup in Auto Attendant to find the extension they want to call, the call completes fine. Using the directory lookup works because the call is made by using the SIP URI of the user and not the extension. Therefore, the Refer-To header contains the SIP URI.

If you are having one of the previously listed problems, use the Office Communications Server 2007 R2 Logging Tool to get the TranslationApplication component logs with all flags while you are reproducing the issue. Search for the following entries:

TL_INFO(TF_COMPONENT) [3] <TimeStamp> (TranslationApplication,PhoneNumberTranslator.TranslateNumber:phonenumbertranslator.cs(250))( 0000000001794AAA )calledNumber='126'

TL_WARN(TF_COMPONENT) [3] <TimeStamp> (TranslationApplication,PhoneNumberTranslator.GetProfileByName:phonenumbertranslator.cs(628))( 0000000001794AAA )Phone-context is user-default but no user-level or pool-level default defined.

TL_WARN(TF_COMPONENT) [3] <TimeStamp> (TranslationApplication,PhoneNumberTranslator.TranslateNumber:phonenumbertranslator.cs(275))( 0000000001794AAA )Profile='user-default' not found (or invalid)

The log entry, "Phone-context is user-default but no user-level or pool-level default defined," points to the fact that the incoming REFER has defined the phone-context as user-default but there is no default context (location profile) available.

You can set this default location profile at the pool level in the Front End Properties. You can set up location profiles on the following levels:

  • Global level: Right-click Forest, click Properties, and then click Voice Properties. Click the Location Profile tab, and then configure the settings on that tab.
  • Pool level: Right-click the pool that you want to configure. Click Properties, click Front End properties, and then click the Voice tab. Configure the settings on that tab.

After the correct location profile is selected, calls should route immediately using that location profile.

Summary

In summary, there are three pre-requisites for Communications Server integration with Exchange UM 2010 SP1 that are important to keep in mind:

  1. Exchange UM 2010 SP1 works only with Communications Server 2007 R2.
  2. Communications Server 2007 R2 should have all the latest updates.
  3. The Communications Server pool should be defined with a default location profile.

Keywords: ocs, um, interop, location profile, user-default, phone-context, Refer, Refer-To, cu5, unified messaging, exchange, call transfer, key mapping

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