10.5 Cisco Unified Mobility MGCP or SCCP Gateway PSTN Access

This topic describes how to implement Cisco Unified Mobile Voice Access when using MGCP or SCCP PSTN gateways.

  • The Mobile Voice Access application requires a dial peer configuration on the voice gateway.
  • PSTN calls received on an MGCP- or SCCP-controlled interface are processed by Cisco Unified Communications Manager:
    1. Dial peer configurations are ignored.
    2. Mobile Voice Access call application cannot be triggered for incoming PSTN call.
    3. Cisco Unified Communications Manager must send incoming PSTN calls to an H.323 gateway to run the Mobile Voice Access application.
    4. Mobile Voice Access application sends the call back to Cisco Unified Communications Manager Mobile Voice Access media resource.

On the voice gateway, the Mobile Voice Access application is configured and triggered as part of a voice dial-peer application. Dial-peer matching takes place only if the gateway provides call control functionality. When MGCP or SCCP is used to control voice interfaces that receive incoming PSTN calls, the gateway no longer has complete call control. Call control is passed to Cisco Unified Communications Manager. In this case, the Mobile Voice Access application cannot be started because no dial-peer matching process takes place.

To use Mobile Voice Access in such an environment, the Cisco Unified Communications Manager must forward calls that are received from an MGCP- or SCCP-controlled interface to an H.323 gateway, to start the Mobile Voice Access application. From then on, the call treatment is like an H.323-only environment, except that the outbound PSTN call is established via the MGCP gateway.

Mobile Voice Access Call Flow with MGCP or SCCP PSTN Gateway Access

This figure shows a call flow in an MGCP or SCCP gateway environment.

The incoming PSTN call is received on an MGCP-controlled interface. The Cisco Unified Communications Manager forwards the call to an H.323 gateway. On the H.323 gateway, the Mobile Voice Access application is started. The caller can be authenticated and can define the final destination for the call. The caller is then connected to the Mobile Voice Access media resource, from which the outgoing call is placed on behalf of the caller office phone (2001). The Cisco Unified Communications Manager establishes the outgoing call via the MGCP gateway.

Note

The H.323 gateway functionality can be combined on the gateway that receives the PSTN call on the MGCP-controlled interface. In this case, only one gateway that provides MGCP and H.323 signaling is required.