Cluster over wan - calling during outage

[abcronin]

Hi NetPros

I have a customer with 2 x subscribers that are clustered over a WAN, there are uses and ip phones at each site registered to their local CUCM subscriber server.

There are also 2 x unity cxn servers that are also clusted over the WAN and registered to both CUCM servers.

Dial plan is configured with AAR

Site A

CUCM

Unity Publisher

Site B

CUCM

Unity Subscriber

The customer simulated a WAN failure and attempted to make calls between each site below are the results:

Phone registration still showed remote phones were registered to the callmanager even though the 2 sites were isolated from each other.

Phones at Site A could dial Unity with no issue, but could not dial phones at site B, calls did not route over PSTN.

Phones at Bite B could not dial unity and could not dial phones at Site A.

Versions:

CUCM 8.5.1

Unity 8.5.1

Questions are:

1. Why would the phones still show as registered to cucm when the cluster was broken?

2. Is there a timeout on the registration state through ICCS?

3. Would AAR work in this case or do we need to use Call Forward on Unregistered?

4. Why wouldn't the phones at Site B be able to dial the local Unity cxn server?

Thanks in advance

Cheers

Andy

[Jaime Valencia]

AAR is NOT for WAN failure, AAR only works when you configure locations and the BW is exhausted, THEN AAR will happen.

HTH

java

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[abcronin]

Thanks Java appreciate the reply

Realize and happy that AAR wouldn't work in this case, so what are the options here to enable calling between the 2 sites when the WAN is down, would Call forward on Unregistered work?

I would have thought that this would be in the SRND?

Both CUCMs seem to keep the registration state for 20-30 minutes after the link was broken so did not follow any callcorwards nor could Site B dial the local Voicemail system.

Cheers

Andy

[abcronin]

Hi all

Anyone able to help explain phone registration timeouts and how best to provide calling between sites that have local cucm servers when there is a wan outage?

Thanks

Andy

[Chris Deren]

Call forward on unregistered is your only option. This gets set per DN.

Chris

[nicolewonghy]

Hi all,

I have internest to know, how long the timeout is, after wan link is down, the remote phone status can change to "unregister"? Really need 20-30 minutes?

And why the Subscriber will know the remote ip phone unregister? Is it because the ICCS link is down, and the phone status will be purged after certain timeout?

Thanks for help.

Thanks,

Nicole Wong

[abcronin]

Hi Nicole

The phones do change to unregistered on the local subscriber within a minute or so, the issue I had was the WAN outage simulation wasn't correct and still allowed for connectivity from the ip phones to the other subscriber.

So using the CFU will work during an outage.

cheers

Andy