cluster size matters to design CUCM

[Rajib Shovan]

Hi All,

As per Collaboration 10.X SRND deployment models: common design criteria>size, it states  

"size generally refers to the number of users, which translates into a quantity of IP telephones, voice mail boxes, presence watchers, and so forth."

and the term is used in call processing design:

"On larger systems with more than 1250 users, Cisco recommends a dedicated publisher to prevent administrative operations from affecting the telephony services. A dedicated publisher does not provide call processing or TFTP services running on the node. Instead, other subscriber nodes within the cluster provide these services."

Can you please clarify the term "number of users". Is it the total count i.e. summation of number of phones, voicemail boxes, gateways etc.?

Thanks,

Rajib

[Rajan]

Hi Rajib,

It usually refer to the number of IP telephony users who has an IP phone registered in the system with/without voicemail, presence enabled and do not include gateways. In 10.x, you might also need to consider the number of end users configured to specifically use for any features like mobility.

HTH

Rajan

[Rajib Shovan]

Hi Rajan,

Thank you for the clarification.

Regards,

Rajib

[HARIS_HUSSAIN]

Number of Users generally refer to Number of IP Phones or Soft phones which are registered to CUCM.

V

[Rajib Shovan]

Thanks Haris. Regards

[Manish Gogna]

Hi Rajib,

We size our cluster nodes based on users when it comes to OVA's ( with an assumed 1:1 mapping between users:devices ),  but in fact the actual sizing limit depends on the number of registered devices on a node.  A 10K user OVA VM node can actually support well beyond 10K users (up to 160K end users in terms of users defined within the database, but not in terms of users with devices) but  it supports no more than a *maximum* of 10K devices. It is perhaps less than intuitive to size our OVAs based on number of users when the limit actually lies with the number of devices…but it is what it is and if we assume a user always has at least one device, then sizing based on maximum number of users per node/OVA does make sense.

HTH

Manish

[Rajib Shovan]

Thanks Manish. 10.x cluster can support 40k devices with 8 call manager nodes. So if we consider HA design 1:1 (secondary call manager for every primary; 4 primary cm with 4 secondary), we need to use 10k user OVA. Considering same HA 1:1 design, if we use 5k user OVA, cluster can support maximum 20k devices. Is my understanding ok. Please correct me if it's wrong.

Regards,

Rajib

[Manish Gogna]

Hi Rajib,

Yes, that is correct.

Manish

- Do rate helpful posts -

[Rajib Shovan]

Thanks Manish.