Dial-Peer failover

Unanswered Question
Jun 4th, 2007

Is there another command to use for dial-peer failover other than the h225 timeout tcp establish command? I have set this command to 3 seconds, but it is still taking 15 seconds for the router to use the failover dial-peer. What can I do to speed this up?



I have this problem too.
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deepagup Sat, 06/09/2007 - 11:31

The most suitable command for you use will entirely depend on the nature of the problem that is preventing the call from going out of one dial-peer. But, try putting in the following commands:

voice service voip


h225 timeout setup 3

h225 timeout t302 3

Let me know if this helps.

Jason Aarons Sun, 06/10/2007 - 16:30

I had a similar issue I opened a TAC case on last month, here was the response;

to give the

h225 timeout I bit more time, 4 seconds is the usual and in most cases we do not use the "h225 timeout setup 1" command and instead use the "h225 timeout tcp establish 4" with 4 seconds to establish the call. By default the IOS gives the call establishment 30 seconds and this is not recommended since if you have dial-peers that need to fail over to other call managers if they are not available such as pub or sub the call can timeout before it even hits the other dial-peer and is sent to the secondary call manager.

Jason Aarons Sun, 06/10/2007 - 18:48

The command ?h225 timeout t302 3? only specifies a timeout for dial-peer matching. In this case it allows 3 seconds for the t302 timer to complete the dial-peer match before timing out.

I have also set up a lab to confirm in what is needed for preserving calls while fail-over occurs. There are only 2 things needed to preserve the call please review the following:


Please configure call preserve on the h323 gateway:


voice service voip


call preserve limit-media-detection


For further information please review the following link:

Configuring the Gateway



Please set the "Allow Peer to Preserve H.323 Calls" parameter to True on call manager.

From Service -->Service parameters --> From the Service menu select Cisco Unified CallManager  click Advanced  Scroll to the Clusterwide Parameter (Device ? H.323) section  Set the "Allow Peer to Preserve H.323 Calls" parameter to True  At the top of the screen click Update.

For further information please visit:

Configuring Cisco Unified CallManager


If you would like further information regarding call preserve please visit:

Configuring H.323 VoIP Call Preservation Enhancements for WAN Link Failures http://www.cisco.com/univercd/cc/td/doc/product/software/ios123/123cgcr/vvfax_c/callc_c/h323_c/323confg/4gwconf.htm#wp1149764


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