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Community Member

dial-peer preference

Hi all, I have a dial-peer with no preference and another dial-peer with preference 10 which is a backup. I use 2 dial-peer to outbound calls to remote gatekeeper1 (dial-peer 1) or remote gatekeeper2 (dial-peer 2). Usually outbound calls match gatekeeper1 with higher preference but sometimes also gatekeeper2 (even though gatekeeper1 is working properly). Is there any other way more then just setting preference to route outbound calls this way?


Re: dial-peer preference

One possibility could be that Gatekeeper1 is not responding to some request in a timely manner. If the request to Gatekeeper1 times out, then the router will use the dial-peer with the next preference and try Gatekeeper2.

By enabling "debug h225 asn1" on the gateway, you should be able to see if this is the case.



Community Member

Re: dial-peer preference

thank you, I'm going to try. Actually I have a "local" gatekeeper, 2 remote gatekeepers with high preference (one is near, the other really not) and a backup remote gatekeeper (dial peer preference 10). Could it be that my gatekeeper use round robin so when it sends calls to the far remote gatekeeper there is a time-out and so the call is switched to the backup gatekeeper?

thank you

Cisco Employee

Re: dial-peer preference


So it really depends how gatekeeper are configured. If they are clustered together, then gatekeeper with higher priority will route the call to its destination.

In this case if you have 2 dialpeers pointing 1 to primary GK and other to secondary GK. If a call fails on the primary,it depends on what is the cause code of that failed call? As an alternative you can use "voice hunt xxxxx" command in the global mode to reroute the call based on the cause code received from other side. It will hunt the next dialpeer.

Another option is to use alternative endpoints and prioritize them.


You can also set hunting preferences on the dialpeers so that the first dialpeer will match:

C2811(config)#dial-peer hunt ?

<0-7> Dial-peer hunting choices, listed in hunting order within each choice:

0 - Longest match in phone number, explicit preference, random selection.

1 - Longest match in phone number, explicit preference, least recent use.

2 - Explicit preference, longest match in phone number, random selection.

3 - Explicit preference, longest match in phone number, least recent use.

4 - Least recent use, longest match in phone number, explicit preference.

5 - Least recent use, explicit preference, longest match in phone number.

6 - Random selection.

7 - Least recent use.

Community Member

Re: dial-peer preference

hi, thank you for your answer, can I show you how my gatekeeper is configured?


zone prefix Gk-C 50*

zone prefix Gk-A 70*

zone prefix Gk-B 70*

end-point gateway h323:

dial-peer voice 100 voip

preference 10

destination-pattern .T

session target ras

tech-prefix 50

codec transparent

dial-peer voice 200 voip

destination-pattern .T

session target ras

tech-prefix 70

codec transparent gatekeeper A is the preferred one and B is backup for the same operator. Gatekeeper C is an other operator. I've never seen call to gatekeeper B.. most to gatekeeper A some to gatekeeper C.

I tried dial-peer hunt 3 but I still get the problem sometimes.

How can I see why a call is outbounded to remote gatekeeper C ?

Cisco Employee

Re: dial-peer preference

Thanks for the config. In your case this GW is registered to GKA. Primarily it should always use GKA unless there is a IP failure and it is not reachable, then GKB should be used. I recommend you to use GK clustering for GKA and GKB. It is a seamless process.

Now since you are using tech-prefix routing in this case, GK will route the call based on tech-prefix match.

You will want to manually define zone prefix's

and zone prefix priorities in your gatekeeper.

Within the context of zone prefix configuration you have the option to define gateway priorities.

Use the gw-priority option to define how the gatekeeper selects gateways in its local zone for calls

to numbers beginning with prefix e164-prefix. Use values from 0 to 10. A 0 value prevents the

gatekeeper from using the gateway gw-alias for that prefix. Value 10 places the highest priority on

gateway gw-alias. If you do not specify a priority value for a gateway, the value 5 is assigned.

In addition, you will want to use the technology called RAI. This is because the T1 will not

unregister with the gateway if it goes down and the GK will not know that it can't route the call to

the gateway just because the T1 is down. With RAI, the gateway and the gatekeepers are constantly

talking about the availability of the T1.

Here is a link for defining zone prefix priorities.

Here is a link For RAI.

Hope this helps


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