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New Member

CUCM Design for 3K user

Dear All

is Scenario#1 is valid to design 3K user CUCM cluster, or i Have to stick with Scenario#2? which one of those is recommended

Scenario #1

use 2 Primary CPE (Call processing engine) each have 2500 user ( in addition to 2:1 redundancy  for Secondary (Backup) CPE) ==> total will be 3 subscriber CPE, plus 1X2500 user ova for publisher ( any issue running 2500 ova as publisher for 3K user ? or this only affect number of devices).

so as a total i should have 2 UCS server each run 2X2500 ova for HW sizing


Scenario #2

use 1 Primary CPE (Call processing engine) have 7500 user ( in addition to 1:1 redundancy  for Secondary (Backup) CPE) ==> total will be 2 subscriber CPE

plus 1X7500 user ova for publisher.

so as a total i should have 2 UCS server one run 2X7500 ova  and one run 1X7500 ova for HW sizing.

Last note according to SRND Publisher recommended to be the same size as other subscribers, but my question can we little deviate from Ova size limit like run 3K user using 2500 ova publisher? Any special consideration for TFTP?


CUCM Design for 3K user

I would use combination of both

2x7500 ova subs each sub in different UCS server and distribute the phone registration among both with back up 1:1

also use the same for MOH and TFTP use one server with a back server as 3k is not very large number otherwise you can use a separate cucm for tftp,MOH ..etc

hope this help

New Member

CUCM Design for 3K user

Thanks Marwan , but in this case

1- i need 2 ova for CPE sub (1:1 redundancy) , 1 Pub , 1 as TFTP/MOH ==> so total of four VMs

2 - just to understand any issue from design prospective using  2500 ova for two primary Sub , (and one 2500 Ova for Pub  keeping in mind 3K user), since if Distribute the users over the two 2500 ova primary CPE and use backup 2500 ova CPE (2:1 redundancy) i have an issue only if both primary CPE fails? is it right , but this can work

3 - last things the Pub Ova is related to user size, i mean 2500 ova for Pub can handle Database for 3K user, any deep info about Pub Database capacity and related Ova size ??since we deviate little form Max number of user.



CUCM Design for 3K user

Hi Ahmed


1- you need 3x ovas/VMs the MOHD/TFTP can be used with the other servers ( optional )

2- as long as your HW can support the 7K ova its better to you use 2subs with 1:! back up

3- the 2500 is for the registration not Pub DB, DB can Handel the max number fo registrations depending on the CUCM version, like 8 and later you may have up to 40K

hope this help

New Member

CUCM Design for 3K user

Thanks Again Marwan

its clear now, but you mention 3 ova ?, it should be 4 ova not 3 (2 Call Processing Sub, 1 TFTP/MOH , and 1 for Pub)?

CUCM Design for 3K user

I mentioned 3 ova because you can distribute Moh and TFTP services across the sub servers not on a dedicated one if you like as 3k users is not too large

Hope this help

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