Can someone show me how to configure 2 h.323 gateways to failover to one another w/call manager

Unanswered Question
Aug 11th, 2010

Hello - I'm not sure on how to make this work.  I need my primary h.323 gateway, Cisco 1900 router, to failover to the seconday h.323 gateway, cisco 1900 router, when the primary fails.  We are pushing t1s/PRIs.  Cisco Call Manager is routing the calls to the gatways.  Thanks

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Felipe Garrido Wed, 08/11/2010 - 13:23

You'll need to add both H.323 gateways to callmanager and use the Route Group configuration to setup the order in which you want them to be used.

You'll then need to add the Route Groups into a Routelist and apply it under the Route pattern


gil.guevara Wed, 08/11/2010 - 13:35

We did - see attached.  We can hit router when we make it the primary, but whe when try to make it failover it won't take the second.

kgroves42 Wed, 08/11/2010 - 14:15

Try Changing the Service Parameter  "Stop Routing on User Busy Flag" on Call Manager to false.

Jaime Valencia Wed, 08/11/2010 - 17:27

There are two options for the failover, in CUCM change this 2 service parameters:

Stop Routing on Unallocated Number Flag = False
Stop Routing on User Busy Flag = False

Otherwise CUCM won't hunt to the next GW.

Or add this command to the GW

no dial-peer outbound status-check pots

This has been asked a lot of times before, please try searching for answers before posting.



If this helps, please rate

gil.guevara Wed, 08/11/2010 - 18:33

I tried ithe Services Parameters and it didn't work.  A TAC engineer told me it couldn't be done with H.323 and that MGCP can.  Is he right?

Tracy Larson Thu, 08/12/2010 - 05:45

I am sure this can be done with H323. I have a question for the support community on this though, cant he just add a voip dial peer with a lower preference and point that to his second H323 gateway and all is good? You wouldnt even need to add the second gateway to a route group either correct? Although that would be the obvious way of handling it.

gil.guevara Thu, 08/12/2010 - 07:02


I think you are refering to "overflow" and not "failover".  I need to be able to failover automatically to the second gateway should the PRIs or the server on the primary fail.  The second gateway will take over and feed the traffic into its secodary server.

however - I will need to incorpate overflow too, but after I can get the failover to work.  Thanks

gil.guevara Thu, 08/12/2010 - 09:17

Tracy - can you give me an example fo this solution please?  Thanks

Tracy Larson Thu, 08/12/2010 - 10:07

For overflow I believe you would just create a voip dial-peer with a lower preference with the session target pointing to the ip address of the gateway you want to overflow to.


if your pots dial peer for normal operation on the gateway looked like this

dial-peer voice 1 pots
translation-profile outgoing fallback
preference 1
destination-pattern 8[2-9]......
port 0/1/0:23
forward-digits 7

Then the voip dial peer for overflow might look like this when that is unavailable.

dial-peer voice 2 voip
preference 4

destination-pattern 8[2-9]......
modem passthrough nse codec g711ulaw
voice-class codec 1
voice-class h323 1
session target ipv4:Overflow Gateway IP address

incoming called-number .
dtmf-relay h245-alphanumeric
fax rate disable
no vad

Java or Bill will be able to say if this would work correctly or not.

gil.guevara Thu, 08/12/2010 - 08:13

I tried this and it didn't work.  TAC checked my configuration and said it was OK, but he also said the failover won't work because it's h.323.  I'm not sure what to do...other than go with MGCP.  Thanks

gil.guevara Thu, 08/12/2010 - 08:59

In H.323 the failover works only when the primary gateway itself goes off-line, and not when the

server it's feeding or it's PRIs go down.  Just tested this.  Thanks

gil.guevara Thu, 08/12/2010 - 09:25

Can someone give me an example on how to make one gw overflow to a second gateway?  I might be able to use this as an alternate solution.

asharsidd Thu, 08/12/2010 - 12:01

I think if you have properly configured a Route List with both gateways under Route Groups then if one fails or PRI not available then a call would take the 2nd gateway. As described above set the parameters Stop Routing on Unallocated Number Flag = False and Stop Routing on User Busy Flag = False.

gil.guevara Tue, 08/24/2010 - 08:36

We got this to finally work - It turns out the Dial-peers that were in place for the FXS ports were conflicting.  Thanks for all the input.

But now I have another issue - I need a third failover option

Gateway1 -> Gatway2 -> Toll free number offnet

The logical way is to have a translation pattern that takes the calls bound for the gatways and translate them to the toll free number.  The problem is, how do tyou get those calls to hit a translation pattern when the two gatways are down?  Any ideas will be gratly appreciated.


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