Max simultaneous On-Net calls supported by CUCM 4.x

[ktran-anet]

Does anyone have any information on this?

[Brandon Buffin]

I'm not sure Cisco quantifies this. They do give the following numbers for 4.x.

Maximum of 7500 IP phones per Cisco CallManager server (configuration-dependent)

Maximum of 100,000 busy-hour call completions (BHCCs) per Cisco CallManager server (configuration-dependent)

Eight Cisco CallManager servers per cluster

Maximum of 250,000 BHCCs per Cisco CallManager cluster (configuration-dependent)

Maximum of 30,000 IP phones per cluster (configuration-dependent)

From this doc:

http://www.cisco.com/en/US/prod/collateral/voicesw/ps6788/vcallcon/ps556/product_data_sheet0900aecd801979f0.html

Hope this helps.

Brandon

[ktran-anet]

Right, I couldn't find that information anywhere on CCO or Google either. But provided that Cisco supports max 30,000 phones per cluster, would that mean that if all 30,000 phones go off-hook and make on-net calls to each other simultaneously, would it bring the network down? I guess, it would depend on how much bandwidth you have, codec, CPU, memory, MTP, software or hardware conferecing, etc., right? Just wanted to see if anyone would agree with me on that.

[Brandon Buffin]

Yes, I think the answer certainly depends on the factors that you mentioned. My thought is if a given cluster supports 30,000 phones, it should support 15,000 simultaneous On-Net calls (Half of the phones on a call to the other half). The odds of this ever happening I would say are slim to none.

Brandon