When you are configuring a dial plan and call routing, you can combine Unified CVP features (such as Location Based CAC, SigDigits, SendToOriginator, LocalSRV, and Use Outbound Proxy) to achieve your desired effect.
The following priority and conditionals are used to formulate the destination SIP URI for the outbound calls made by Unified CVP. This description covers CONNECT messages which include labels from the ICM (VXML GW, CUCM, etc), as well as calls to the ringtone service, recording servers, and error message playback service.
The algorithm for creating the destination SIP URI host portion for outbound calls, given the ICM label is as follows.
1. At the start of the algorithm, the ICM label is provided. It may already have the Location siteID inserted by the ICM subsystem, or SigDigits may be prepended if used. For network VRU labels, the ICM subsystem passes in the entire prefix + correlation ID as the label.
2. If Send to Originator is matched for the Unified CCE label, the IP or hostname of the caller (ingress gateway) is used by the Unified CVP algorithm, which returns the SIP URI. The setting for SendtoOriginator only applies to callers who are on IOS gateways (the SIP UserAgent header is checked), because non-IOS gateways do not have the CVP "bootstrap" service used by the Cisco VXML gateway.
3. If use outbound proxy is set, then use the host of the proxy - return SIP URI.
4. If local static route is found for the label - return the SIP URI.
5. Else throw RouteNotFoundException WARNING trace in the logs.
