Verifying and Troubleshooting SRST

To verify your SRST configuration, you should initiate a failover condition and thoroughly test typical calls and features. To minimize the impact to operations, follow these steps to create a test bed:

Step 1.

Create an SRST reference.

Step 2.

Create a new device pool using the SRST reference from Step 1. All other parameters should match your existing device pool that you used at the remote site.


Step 3.

Assign the new device pool to IP phones for testing. You should test with at least three IP phones. If you are implementing COR, you need at least one IP phone per incoming COR list.

Step 4.

If no IP phones exist, or if you are testing an MGCP gateway, add a null route to CallManager.

ip route null0

Step 5.

If IP phones do exist, place the test phones in their own VLAN. Create an extended access control list (ACL) to block traffic from this VLAN to the CallManager addresses.


To fully test MGCP gateways, you need to invoke MGCP Gateway Fallback. This impacts all IP phones and should be planned accordingly.

The most useful tools to troubleshoot SRST are the show ephone and debug ephone commands. These commands show any registration issues. SRST issues are commonly related to the dial plan. To troubleshoot dial plan issues, use the debug voice dial peer command. For ISDN circuits, use debug isdn q931.

The debug voice ccapi inout command can also be useful, but this debug generates significant output. You should use this as a last resort.

Part I: Voice Gateways and Gatekeepers

Gateways and Gatekeepers

Part II: Gateways

Media Gateway Control Protocol


Session Initiation Protocol

Circuit Options

Connecting to the PSTN

Connecting to PBXs

Connecting to an IP WAN

Dial Plans

Digit Manipulation

Influencing Path Selection

Configuring Class of Restrictions

SRST and MGCP Gateway Fallback

DSP Resources

Using Tcl Scripts and VoiceXML

Part III: Gatekeepers

Deploying Gatekeepers

Gatekeeper Configuration

Part IV: IP-to-IP Gateways

Cisco Multiservice IP-to-IP Gateway

Appendix A. Answers to Chapter-Ending Review Questions


Cisco Voice Gateways and Gatekeepers
Cisco Voice Gateways and Gatekeepers
ISBN: 158705258X
EAN: 2147483647
Year: 2004
Pages: 218 © 2008-2020.
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