Route Group and Route List related question

Unanswered Question
Feb 27th, 2007

I have a site with two routers (voice gateways) with an ISDN PRI connected to each of them. I had one of the PRIs working for 2 months (connected to one gateway) and recently we have added the second PRI (on the second gateway). IP vice, the gateways are running iBGP between each other and can get to each other and both are active routers (no HSRP). I had one gateway in my route group since only one of them was doing voice and just recently I have added the second gateway (H323) into the route group (Distribution Algorithm being 'Top Down'). So right now the route-group has two gateways. Basically the idea is to make use of the second gateway and PRI when the first PRI goes down. When I tested bringing the first PRI down, phones could not dial out or in. I got a chance to reset the Route-Group and Route-List on the CM, but did not reset the route-patterns where these route-list is applied. Is a reset on the phones or route patterns needed to make it work? I just want to explore my options before I try this again.

One other question in my mind is, even if the first PRI goes down, the gateway would still be up and registered with the CM. How exactly does the route-group make use of the second gateway?

Any documentation lead is also appreciated.

Thank you,

Ranjani

I have this problem too.
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mchandak Tue, 02/27/2007 - 08:25

For the call to be re-routed the msg recieved from the gateway is what is more important. Can u collect detailed CCM traces for a call and attach it here. That would help us identify the msg being received from the gateway and what can be done about it.

ranjanibharadwaj Tue, 02/27/2007 - 08:47

Thank you for the quick reply, but unfortunately I had not turned on relevant debugs and I won't be able to test for few days now. Therefore, I was trying to research what I am trying to do is valid and if it might work. Any feedback in the configuration sense? When a call goes out from my IP phone and if the PRI is not up, would the gateway signal the CM to notify that PRI is not available and therefore it needs to make make use of the other gateway?

Thanks in advance.

fred.s.mollenkopf Tue, 02/27/2007 - 08:43

Ranjani,

In the case of a H323 gateway you will need to adjust a service parameter in CallManager. If your PRI is down then the router should report back to CCM a cause code 1 unallocated number. **Editing because I had the syntax wrong** By default, Stop Routing on unallocated number is set to True, which is the CCM equivalent of that cause code. You need to set this to false since the default stops routing. Assuming your CCM Route lists and groups are working (which I do recommend a reset or the new changes won't take effect) then it should failover to the alternate H323 gateway.

Now if your H323 gateway is down then CCM will failover by the H225 timer for TCP establishment to the 2nd gateway. I know that off the top of my head on the router, but I would have to look that up for the CCM Service parameter and post. If you have two CCM servers make sure both gateways have something similiar to this below on their IOS.

voice class h323 1

h225 timeout tcp establish 3

dial-peer voice xxx voip

description All dial-peers to CCM

voice-class h323 1

Please rate any helpful posts

Thanks

Fred

ranjanibharadwaj Tue, 02/27/2007 - 08:57

Fred,

There you go. Thanks for the information. This is what I was looking for, I thought there had to be something to make it roll to the second one. I will research further.

Thanks again.

Ranjani

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