Automate routing in WAN failover.

Unanswered Question
Apr 23rd, 2008

I have CallManager cluster in two locations and there is WAN between them. When WAN fails I want to translate calls between internal users so they have to exit to PSTN to the another site. In this case AAR isn't useful. I'm trying to do that with translation pattern but it work only for numbers that aren't configured in CallManager. If there is much of internal unregistered phone CallManager returns immediately busy tone and doesn't try to translate and route the call anymore.

Thank in advance.

Best Regards,


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kelvin.blair Wed, 04/23/2008 - 09:02

I'm not understanding the following statement "I have CallManager cluster in two locations and there is WAN between them". Do you have two separate Clusters and communicating via intercluster trunk or Single cluster and doing Clustering over the WAN?

Jaime Valencia Wed, 04/23/2008 - 12:20

configure a route list with the ICT and the PSTN GW and assign it to the route pattern, under the route group configure the necessary call handling to the PSTN GW to add the digits you need to route the call to the PSTN



if this helps, please rate

kelvin.blair Wed, 04/23/2008 - 13:15

That is the same thing that I was thinking, but wanted to be sure of the topology.

z.zdravkov Wed, 04/23/2008 - 22:17

There is a publisher in the first site and subscriber in the second site. I'm talking for one cluster. ICT doesn't work in this case.

iptuser55 Thu, 04/24/2008 - 00:25

If I`m reading this correct, you have a Pub in one site and a sub in another. When you lose the WAN between the two you wish for internal cals to still work between them ?

A lot depends on your set up

if all your incoming DDI are at the Pub site then PSTN wise there is not a lot you can do unless you have some telco lines there as back up- If you do have Telco lines at the Sub site as back up you need to map these to the extensions at the Sub site for the following to work

1. As AAR will only work when the WAN is busy you could change the location setting for the Sub site to 1k so to force AAR in place- Sub needs its own Telco lines

2. Use BAT to change the Partitions in for the extension at the SUB site to a WAN_Parttion_outage? which points to a Translation already set up to route calls to the Sub calls from the Pub site to Telco lines at the Sub site- again dependant on having Telco at Sub

Sub to Pub- Since you can not make changes to the Sub site phones so the above options are out, you could have a hidden Translation already set up e.g * followed the extension prefix at Pub so again to route the calls to the Pub via the Telco - again dependant on having telco lines at the Sub site

z.zdravkov Thu, 04/24/2008 - 04:27

It is correct that I have Pub in one site and Sub in the another. I also have PSTN connectivity in both of them and DID numbers.

I'm trying to understand your solution but I'm a little messed up.

If we set AAR and location of 1k I think no calls can cross through WAN even it is up. This can be done for both or one of the sites but I didn't get what is our privilige to do it.

Thanslation are hapaning after internal DNs match so they are unusable in this case.

Please describe me more deeper what is your solution. It is very interesting for me I think many other people.

By the way my CCM version is 5.1(3) there isn't forward unregistered.

Thank you very much.

Best Regards,


iptuser55 Fri, 04/25/2008 - 05:20

AAR- Currently the AAR setting is used for bandwidth control and can not be used when the WAN between the two sites are is down. If you reduce the location between the two sites to 1k when the WAN is out AAR will then be invoked

Translations-The DN`s at the two sites will need something to make then unique - maybe description field.

Normal Op - Dial the DN at Site B the call is routed as an internal call. what you want to do is to route the call out via PSTN

Create 2 x Partition called PSTN_TO_SITE_B , WAN_DOWN....

Create a TP for the DN`s at Site B and translate them to their PSTN

Site B extension 45xx- Normal DDI 121055545xx

Add a TP 45xx

Partition "PSTN_TO_SITE_B......"

Add a translation to 121055545xx

Ensure that no-one has either Partition in their CSS so it is not active

Use BAT to identify Site B users via the description I mentioned

Modify only Site B users normal Partition and change then to WAN_DOWN........,

Now change the Partition in the newly created TP for 45xx to the partition you normal assigned to Site B users

Now when Site A users dial the 45xx extension which points to the new TP and is translated to Site B`s DDI

SITE B users can still dial each even though you have changed their Partition and the do not have it in their CSS since the Sub is not aware of changed and there is no DB replication

hope that makes sense

z.zdravkov Tue, 04/29/2008 - 06:46

I think that if I made described configuration I will be able to dial from site A to site B only by their internal numbers. I'm looking for automatic failover variant.

I also didn't get where is AAR involved in your last description.

Why do I need to make TP if I have AAR?

What CSS should I use?

Thank you.

Best Regards,


iptuser55 Tue, 04/29/2008 - 08:38

The AAR and translatins are two different options both of which are manual- there isn`t any automatic way as in AAR feature everything is manual in that you need to change something in CCM but the users will be unaware. The AAR is used to trick the Pub in to stating there is no bandwdith available when the WAN is down so to force calls across PSTN

z.zdravkov Thu, 05/01/2008 - 00:46

Unfortunately I'm looking for automatic failover option. Manual failover doesn't help me a lot.

Thank you very much for your time. If you have any other ideas I will be happy to hire from you.

In case if we can't find way yo it the users will call just the external number.

Best Regards,



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