Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

AAR confusion

Im trying to setup the following:

Remote location tries to dial another location and gets a busy signal, it will automatically reroute and dial through PSTN.

So if my remote location calls say 55-4000, how do I tell the remote location to reroute to their local PSTN to dial 408-555-4000?

Remote Location A is Up and running.

Remote Location B is down for some reason and we cant dial through the WAN. The call should be re-routed.

What are my options?

CUCM 6.1.4


Cisco Employee

Re: AAR confusion

AAR user 2 things to know how to dial:

A) External phone number mask

B) AAR prefix

In this case DN 554000 should have set a mask of 4085XXXXXX and the AAR group should prefix it with 91 so the call goes thru the PSTN

Remember AAR is to be used with CAC and locations, upon BW exhaustion AAR kicks in

For your scenario i think it would be best to configure the CFUR to dial the whole DN for the PSTN.



if this helps, please rate



if this helps, please rate

Re: AAR confusion

Thanks Java. Im looking at it and have some what an idea.

Take a look at my steps:

Create AAR Group

Create AAR CS/PT

Create Translation Pattern for translating site code to PSTN

Reorder the PT in the CSS so the AAR CSS for translations is lower. (meaning the line will first try the Route Pattern to the WAN, if no luck, go to next pattern in the CSS which is the AAR Translation pattern)

Im playing with the called party transform mask to make this work.

To make matters more confusion, I have a remote location, that is the first of many of this cluster. All site codes will go through one h323 gateway, then off to other h323 sites PBX. So Im not sure if RSVP will work with this correct? Im wondering if I should simply not use AAR and CAC and just use CSS/PT, translations and Route patterns to accomplish this correct?

New Member

Re: AAR confusion

Java summed it up in his post, but i will add a few more notes.

To use AAR, make sure the external mask on all destination DNs is configured. This is what the originator uses to make the call through the PSTN.

Make sure the AAR groups and prefixes are configured. Create an AAR dial plan to reroute the calls through, just as you would a normal route, you may also use an existing dial-plan.

Make sure that locations are configured, upon bandwidth overutilization, determined in locations, AAR kicks in.

Make sure the Alternate routing CSS is configured on the device.

I am not sure why you are configuring a translation patter, there is no need to unless performing "AAR/SRST" which is a pain to begin with.

Your last paragraph is a bit confusing. If you plan to gatekeepers, then you can use RSVP.

The last sentence is a bit more confusing, "...simply not use AAR and CAC and just use CSS/PT, translations and Route patterns to accomplish this correct"

Is any case, you must use CSS to determine the allowed destinations. The AAR dial-plan must be part of that CSS.

In order to use AAR, you must use "CAC" or locations. You need "CAC" tp reroute calls, otherwise, there is no way for CUCM to determine if there is enough bandwidth available.

It is a bit more complicated, look up the CUCM SRND for more information

Re: AAR confusion

Thanks for the reply, I will take a look more at the SRND again.

Though, looking at this setup, because the calls are primarily going through an h323 gateway to get to another site, if the site's wan is down or the primary h323 gateway is down, but the phones are connected to CUCM, i had to make a work around.

Basically what I did was I created a Route pattern for each site, then create a route group for each site. Created a route list.

In the route list, I put in the H323 gateway as first try. Next try is the Route list that had the local PRI in it and transformed the number to it's PSTN number. This seem to work fine during our tests. Of course, it's a pain, but the customers requirements to have this was critical.

If all my sites were on CUCM, built it out with locations, regions, RVSP, etc... then AAR would work..... but being that RVSP can not calculate bandwidth with h323 (without a gatekeeper), then I back to the basics.