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Walkthrough Wednesdays

The PSTN calling party is not able to hear the closed greetings configured on Cisco Unity


Core Issue

The Cisco Unity Port Status monitor shows that Unity answers the call. Cisco Unity sends the closed greeting audio stream to the caller, but the calling party is not able to hear the greeting. Internal calls to Cisco Unity function properly, and callers are able to hear the closed greeting.

This is a one-way audio issue that affects calls through the Public Switched Telephone Network (PSTN [Gateway]) into Cisco Unity. This problem results when Cisco Unity sends the Cisco IOS Real-Time Protocol (RTP) packets to the wrong interface on the Gateway. For example, Cisco Unity sends packets the loopback interface instead of the Fast Ethernet interface, which is the "bound" interface for the Media Gateway Control Protocol (MGCP) process.


Issue these commands to confirm that Cisco Unity currently sends RTP packets to the wrong interface on the Gateway:

To resolve the issue, perform these steps:

  1. Issue the no mgcp command to shutdown the MGCP process.

  2. Remove the mgcp bind control and mgcp bind media commands from the router configuration.

  3. Re-issue the mgcp bind commands.

  4. Issue the mgcp command again to allow the gateway to register to Cisco CallManager.

  5. Test the call again and issue the show commands mentioned to verify that Cisco Unity sends the RTP stream to the correct (bound) MGCP interface.