Redundancy topology of CUCM - SRND

Unanswered Question
Jun 1st, 2009

I have Publisher and Subscriber on side A. Now I want to put Subscriber on side B. Side A and Side B connected with 10 Gig interface. Is it normal or I should use new one Subscriber on side B?

New Subscriber server costs a lot and I want to know is it possible to decentralize Publisher and Subscriber.

Thank you a lot

I have this problem too.
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KonradStepniewski Mon, 06/01/2009 - 23:54

Check link about clustering over WAN, this should halp you:

There are some special requirements you have to pass:

- The maximum round-trip time (RTT) between any two servers must not exceed 40 msec for Unified CM 6.0, or 80 msec for Unified CM 6.1 and later releases.

- The expected error rate should be zero. Any errors, dropped packets, or other impairments to the IP network can have an impact to the call processing performance of the cluster.

- Jitter is the varying delay that packets incur through the network due to processing, queue, buffer, congestion, or path variation delay. Jitter for the IP Precedence 3 ICCS traffic must be minimized using Quality of Service (QoS) features.

Keep in mind that Cisco recomends your setup Pub and Sub up to 1250 users: Tue, 06/02/2009 - 01:05

From link

Note You can also combine the features of these two deployment models for disaster recovery purposes. For example, Unified CM groups permit configuring up to three servers (primary, secondary and tertiary). Therefore, you can configure the Unified CM groups to have primary and secondary servers that are located at the same site and the tertiary server at a remote site over the WAN.

Does it mean that I should use 1 Publisher and 1 Subscriber on side A and 1 Subscriber on side B?

KonradStepniewski Tue, 06/02/2009 - 01:26

If you have more than one Sub then you should exclude Pub from call processing function.

Yes, you can do it like you said Pub and Sub on side A and another Sub on side B.

Still you can use Pub on side A and Sub on Side B if you can not spend money on new serever and licenses.

pls, rate if this help Tue, 06/02/2009 - 02:39

Theoretical as I understood , I can use 1 Publisher on side A and 1 Subscriber on side B.

But I want to know how it works on practice? I mean Is it clearly works or you get some issues that didn't expect before ?

MARTIN STREULE Tue, 06/02/2009 - 04:18


This works really well.

The only worry is that the link between the servers is not stable.

The worst thing I ever saw with that was a sporadic link failure which caused a lot of dropped calls and weird issues.

As posted before, have a look in the CUCM SRND chapter "Clustering over the IP WAN".

Be sure to enable "call preserve" to have less issues with PSTN calls.




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