Learn how to use a script application to configure call forwarding in a Microsoft Lync Server 2013 deployment.

In common SIP application scenarios, incoming calls are forwarded to a different user. For example, in team collaboration, a user (A) might want another user (B) to answer IM calls from another user (C) while A goes on vacation. In customer support situations, a call to anyone in a company can be forwarded to an interactive voice responder (IVR) that can dispatch the call to available support staff. The Microsoft Lync Server 2013 SIP Application API supports this scenario by using either script-only or managed code applications, depending on the complexity of the application logic. In this topic, a script-only application is used to forward a call in a Lync Server 2013 deployment.

Forward an IM invite from one user to another user

The following Microsoft SIP Processing Language (MSPL) script shows how to forward a call from a specified user to another specified user. The incoming INVITE is originated from the user, Nuria, as identified by the SIP URI of "sip:nuriag@contoso.com". The application uses the RetargetRequest function to change the original target, Jenny, as identified by the SIP URI of "sip:jennyl@contoso.com" to a different user, Terry, as identified by the SIP URI of "sip:terrya@contoso.com".

Note Note

This script must be registered with a priority higher than that of the UserServiceson the deployed Lync Server instance.
XML  Copy codeCopy code 
<?xml version="1.0"?>
<r:applicationManifest
   r:appUri="http://www.contoso.com/ForwardInvite"
   xmlns:r="http://schemas.microsoft.com/lcs/2006/05">
   <r:allowRegistrationBeforeUserServices/>
   <r:serverFilter roles="ALL"/>

   <!-- handle INVITE requests -->
   <r:requestFilter methodNames="INVITE"
				 strictRoute="false"
				 registrarGenerated="true"
				 domainSupported="true"/>

   <!-- handle no response. -->
   <r:responseFilter reasonCodes="NONE"/>

   <!-- Script-only application. -->
   <r:scriptOnly/>

   <r:splScript><![CDATA[
	 if (!sipRequest) {
	 return;
	 }
	 toUri = GetUri(sipRequest.To); 
	 fromUri = GetUri(sipRequest.From);

	 if (toUri == "sip:jennyl@contoso.com" && fromUri =="sip:nuriag@contoso.com")
	 {
	 RetargetRequest("sip:terrya@contoso.com");
	 return;
	 }
	 ProxyRequest("");
   ]]></r:splScript>
</r:applicationManifest>

When enabled, this application forwards the call intended for Jenny (sip:jennyl@contoso.com) from Nuria (sip:nuriag@contoso.com) to Terry (sip:terrya@contoso.com). After accepting the call, Terry communicates with Nuria on behalf of Jenny. To Nuria, the ensuing conversation seems to continue with Jenny, as she intends, even though when she actually converses with Terry. The SIP messages exchanged between Nuria and Terry in this session have the Toheader that contain Jenny's SIP URI and the Fromheader that contains Nuria's SIP URI. Requests that originate from Terry carry a P-Asserted-Identityheader that contains Terry's SIP URI.

Note Note

Forwarding should not be applied to any session-bound messages.

Similar to forwarding a call, MSPL supports redirection of a call by using the Respond function. This concept appears in the following MSPL example.

  Copy codeCopy code 
	 if (toUri == "sip:jennyl@contoso.com" && fromUri =="sip:nuriag@contoso.com")
	 {
	 Respond("302", "Forwarded to terrya@contoso.com",
"Contact=<sip:terrya@contoso.com>");
	 return;
	 }

In the redirection scenario, the call requester is aware that the call is forwarded to a different target after the call is accepted.

See also