Understanding AAR

[billsayegh]

Hi

Would like to better understand AAR. With AAR you define the AAR group and the alternate number. Is this number then assigned to the the gateway or the phone so that when the AAR is invoked, The the phones or GW CSS will look for this number to know where to route the number that was defined in the AAR.

I would greatly appreciate an overview of how the AAR prefix is then linked to a device and routed via the alternate path which components it is linked to in the configuration.

Thanks

Bill

[Chris Deren]

1. First you create AAR groups where you define prefixes between group, usually "91" where 9 is your off-net digit

2. Assign AAR group to DN of a phone

3. Make sure that the External Phone Number Mask is defined correclty on the phone DN as it is what is used to reach the device

4. Assign AAR CSS to the device

Now, when there is not enough bandwidth between 2 sites based on your defined Location allocation, and user from site A calls user at site B, AAR is invoked. AAR looks at the phone B external phone masks, prefixes it with the prefix assigned to phone A AAR Group, and by using phone A AAR CSS sends the call out via gateway whose route pattern partion is listed in the AAR CSS.

To better understand why you would need more than one AAR Group consider an example:

3 remote sites, A B and C

Sites A and B are in the same area code (Chicago), site C (New York) is long distance site from both A and B

You would create 2 AAR groups: Chicago and NY

The prefix between Chicago and NY would be 91, within Chicago it would be 9. This way when there is not enough bandwidth between site A and B, AAR prefixes 9 (local call, no need for 1), but for call to site C it prefixes 91. Makes sense?

Please rate all helpful posts!

Chris

[thisisshanky]

Also,

In 3.x, you will have to enable AAR using an enterprise parameter. Its disabled by default.

Sankar.

[billsayegh]

Thanks

In the AAR group you define the source group prefix and destination group prefix. Say site A is calling site B and site A is in AAR group 1 and site B is in AAR group 2.

Does this mean that site A will prepend the prefix of AAR group 1 to the called number. Where does site B AAR prefix come into play.

Also does the prefix number added to site A then get searched in the site A calling search space to find a match for this route pattern and route it via the gateway that match the partition for this number in the calling search space.

Thanks

[billsayegh]

Thanks

In the AAR group you define the source group prefix and destination group prefix. Say site A is calling site B and site A is in AAR group 1 and site B is in AAR group 2.

Does this mean that site A will prepend the prefix of AAR group 1 to the called number. Where does site B AAR prefix come into play.

Also does the prefix number added to site A then get searched in the site A calling search space to find a match for this route pattern and route it via the gateway that match the partition for this number in the calling search space.

Thanks

[Chris Deren]

For 2 sites you would never need more than one group, if you have to dial long distance from site A to site B, then you create a AAR group with 91 prefix and assign this group to both site phones. The only reason you would need additonal group would be for local sites, and/or international sites, so different prefixes can be prefixed.

Chris

[startryst]

Please help me to verify my thinking is correct:

A call B, bandwidth is not enough,offnet digit is 9

for example: extension of B is 1111, external phone mask is 2222

So, when AAR enabled, A dial 1111, then translate to 922221111, then go Voice gateway to B, right?

[Chris Deren · Accepted solution]

NO. A calls B, bandwidth is not enough, AAR is invoked. A and B are in the same AAR group which has prefix of 9, CCM prefixes 9 to phone B's external phone number mask which should always be the full e164 number such as 2125551111, in most cases you would use a wildcard mask such as 212555XXXX, so the CCM dials 92125551111 which points to a route pattern->GW and dials out to PSTN. The call arrives at the remote site's GW and gets redirected to CCM and delivered to extension 1111.

Please rate all helpful posts!

Chris

[billsayegh]

Thanks Chris

Can you clarify in the config, when you define two different AAR groups say AAR Group 1 and AAR Group 2 in the config it has AAR Group1 then below this the other AAR Groups which in this case will be ARR Group 2. Now under AAR Group 2 is has Prefix digits from AAR Group 1 and Prefix digits to AAR Group 1.

I can understand prefix digits from AAR Group 1 but what does prefix digits to AAR Group 1 refer to.

Does this mean that you only have one table for AAR Group 1 to AAR Group 2 and the to from prefix covers both directions. If this is the case then it makes sense.

Thanks