Publisher/Subscriber

[CHARLES HEUPEL]

Can anyone tell me if you can mix and match Publisher/Subscriber server models.  For example, if I have a 7825 Publisher can I add a 7835 subscriber or vis versa?

[Rob Huffman]

Hi Charles,

This is a supported model

You can mix/match server models in the cluster design but the 7835 would be a better choice as

a Publisher.

Unified CM Cluster Services

https://www.cisco.com/en/US/docs/voice_ip_comm/cucm/srnd/6x/callpros.html#wp1043559

Hope this helps!

Rob

[David Hailey]

Rob is correct here.  You can mix/match server types within a cluster; however, let me clarify and add a point to his post:

The 7835 should become your Publisher.  It's not just a better choice, it's best practice.  Cisco recommends that, if mixing/matching is required, that the server with the greatest hardware become the Publisher in the cluster.

Secondly, you should avoid mixing matching of Subscriber hardware if at all possible.  This affects cluster capacities and failover ratios amongst other things.  Short example, if you have a 1:1 failover ratio (1 active sub, 1 backup sub) and the primary is a 7845 that is near capacity with registered phones but the failover is a 7835 then in a failover scenario, the 7835 would not be able to support all of the phones that needed to re-home for registration.

Lastly, keep in mind that mixing/matching affects cluster capacities as noted above.  Beyond phones, this includes CTI capacities, MoH streams (if unicast) and so forth so you need to plan for cluster capacity based on the lowest common denominator.  In other words, if the smallest subscriber is a 7825 then the capacity of your cluster should be expected to meet that of a 7825 and no higher.

Hailey

Please rate helpful posts!

[CHARLES HEUPEL]

Thanks for the information.  Would it be possible to start with a 7825 as the Publisher then purchase a 7835 and convert it to the publisher and move the 7825 to a subscriber role?  Problem is we've already purchased 7825s and need to bring them up now.  We recently purchased another company that is looking at a CUCM solution and they have over a 1,000 phones.  So ideally, I would like to go ahead and bring up the 7825s and if we go with CUCM at the other location, buy 7835 and convert it to the Publisher.

Thanks again for all your help.

[David Hailey · Accepted solution]

Rob may have further comment here as well but you could migrate data via

DRS to move from a 7825 to a 7835 as a Publisher in the future. However,

you would have to rebuild the 7825 from scratch in order to make it a

Subscriber within the cluster. Remember, if you have other 1000 phones

(1250 is the actual number) then you need a dedicated TFTP server as well

and a Publisher that only serves as a database. So, regardless of model

of server - your architecture with over 1000 phones at a minimum would be:

Publisher - DB only

TFTP Server - TFTP only, no call processing services

Subscriber (Active) - call processing

Subscriber (Backup) - call processing

The requirement around dedicated TFTP is outlined in various design guides

as well as the SRND.

Hailey

Please rate helpful posts!

On 12/3/10 11:41 AM, "cheupel"

[Rob Huffman]

Hailey,

I can't add anything to this great info my friend

+5 all day long!

Cheers!

Rob