How to make OCS 2007 R2 non-RFC 3966-compliant using RemovePlusFromRequestURI

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How to make OCS 2007 R2 non-RFC 3966-compliant using RemovePlusFromRequestURI

Office Communications Server 2007 Mediation Server uses a plus sign (+) to prefix E.164 numbers in the Request Uniform Resource Identifier (URI) for outgoing calls. Unfortunately, some IP-PBXs don't comply with RFC 3966 and do not accept numbers that are prefixed with a plus sign (+).

As the UCSpotting blog points out:

To make sure that OCS 2007 operates correctly with non-RFC 3966-compliant PBXs, Microsoft released an update for Mediation Server (R1), which is described in KB articles 952780 and 952785. After installing the update, it's necessary to create a configuration file - MediationServerSvc.exe.config - with the following content:

"1.0" encoding="utf-8" ?>
<configuration>
                 <appSettings>
                                <add key="RemovePlusFromRequestURI" value="Yes" />
                 </appSettings>
</configuration>


In OCS 2007 R2, Microsoft changed this slightly negating the need for the above configuration file. There's a new WMI setting, RemovePlusFromRequestURI, which is described in this TechNet article called Enterprise Voice Server-Side Components.


According to the TechNet article, Office Communications Server 2007 R2 introduces two new Windows Management Instrumentation (WMI) settings for Mediation Server. The first new setting specifies how Mediation Server processes E.164 numbers in outbound calls. The second new setting enables Quality of Service (QoS) marking on Mediation Server.

Handling E.164 Numbers in Outbound Calls (OCS 2007 R2)

By default, E.164 numbers in the Request Uniform Resource Identifier (URI) for outgoing calls are prefixed with a plus sign (+). Most Private Branch eXchanges (PBXs) process such numbers without problem. Certain PBXs, however, do not accept numbers that are prefixed with a plus sign.

To ensure interoperability with these PBXs, Mediation Server has a new WMI Boolean setting called RemovePlusFromRequestURI, which has two values: TRUE and FALSE. If your PBX does not accept numbers prefixed with a plus sign, the value for the WMI setting should be set to TRUE, which causes Mediation Server to strip the plus sign from a Request URI for outbound calls. The default is FALSE, which causes Mediation Server to pass the outgoing INVITE's Request URI, To URI, and From URI unchanged.

The TechNet article also discusses compatibility with PBXs that do not support the plus (+) sign.

By default, E.164 numbers in the Request URI of outgoing calls from Office Communications Server 2007 R2 are prefixed with a plus sign. Most PBXs process such numbers without problem. Some PBXs, however, do not accept numbers that are prefixed with a plus sign and do not route those calls correctly.

Additionally, the From headers of inbound calls from some PBXs does not conform to RFC 3966 because they are not prefixed with a plus sign. Microsoft Office Communicator cannot resolve these numbers to the correct user.

To assure interoperability with these PBXs, Office Communications Server 2007 R2 has a new Mediation Server setting for WMI called RemovePlusFromRequestURI. This setting can be set to YES or NO. The default value is NO.

- If a PBX downstream from the Office Communications Server 2007 R2 Mediation server does not accept numbers prefixed with a plus sign, set the value of RemovePlusFromRequestURI to YES. This causes Mediation Server to remove the plus signs from the Request URIs of outgoing calls. It also causes the plus signs to be removed from the To and From URIs.
- If the downstream PBX accepts numbers prefixed with plus signs, leave the value of RemovePlusFromRequestURI set to its default value of NO. This causes Office Communications Server 2007 Mediation Server to pass Request URIs, To URIs, and From URIs unchanged (that is, with plus signs).

UCSpotting's excellent article explains all this, and includes a nice VBscript for how to change the boolean value (true or false). Check it out!


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