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

Unanswered Question
Feb 9th, 2010

Does anyone have any information on this?

I have this problem too.
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Brandon Buffin Tue, 02/09/2010 - 13:27

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:

Hope this helps.


ktran-anet Tue, 02/09/2010 - 13:39

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 Tue, 02/09/2010 - 13:43

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.



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