Cisco Support Community
Community Member

several questions about CCM's spec


Can anyone please help me out understanding some of the spec/feature of CCM. These might be dumb questions, but I just need some clarification and confirmations. Thanks!

1. In the datasheet, it said "Max BHCC 50,000 per Cisco CallManager server". What does BHCC mean?

2. Say I have AS5300 with 96 ports (T1 E&M), will that be counted as 96 devices on CCM or one?

3. How does "Alternate Automatic Routing" works? Am I able to setup somthing like the following.

- 1250* goes to gateway A (

- if all ports at gateway A is full, then it goes to gateway B (

- if all ports at gateway B is full, then it goes to gateway C (

Also, how many redundancy routing can I setup?

4. Call admission control. How does this work?

5. How does an non-Cisco H323 gateway communicate with it? How do I know if the H323 gateway is compatible with CCM?

6. I haven't being able to find ANY TAPI information on CCM3, can someone point me to the right direction?

Much appreciated!

Community Member

Re: several questions about CCM's spec

1. BHCC stands for Busy Hour Call Completions and is a measurement of PBX call processing power.

2. 96 ports on an AS5300 would count as 96 H.323 'devices'. This by the way, is effectively 288 consumed units of the Media Convergence Server (MCS).

3-4. Many H.323 gateways should be interoperable with CallManager but double-check yours with your Cisco design engineer. Check with them on your Alternate Automatic Routing design too. I understand Cisco’s TAC only supports non-Cisco H.323 gateway’s after interoperability and performance tests have been performed. Unless you have an existing gateway in place, go end-to-end Cisco. It could save you a lot of headaches.

5. For information on Call Admission Control, look here

6. TAPI Information was just posted yesterday. Look at this thread

Hope this helps!

Community Member

Re: several questions about CCM's spec


Thanks for the pointer! I got couple more questions based on your answer. Hope you don't mind helping me out here.

1. You mentioned 288 consumed units of MCS. How did this come about?

2. So based on CCM's datasheet, one MCS can roughly handles 26 AS5300 (with 96 port each)?

3. Is there anywhere I can get more information about BHCC and how it will effect MCS's performance?

4. My concern about Call Admission Control, is basicly, that authorized gateway, ip phone, etc can connect to our network and terminating gateway. Does CCM do that or do I need a seperate gatekeeper for it?

Thanks again!

Community Member

Re: several questions about CCM's spec


On point 1 288 is derived beacuse each port has device weight of 3 in the call manager. Depending upon the MCS server you have you will have a maximum loading that the CM can take, the higher the spec MCS the better. For example the Softphone has a weight of 30 so you could not have 2500 soft phones registered with a single CM.

Point 2; Again it would depend upon the MCS being used. If a single AS5300 with 96 ports has a device weight of 288, you couldn't have 26 AS5300 registered on one MCS as this would give a load of 7488. Note even the MCS7835 can have this, I think the max device count for a 7835 is 5000. The max count is derived from all phones, gateways, conferences, uone ports etc connected to the CM

Hope this helps

Community Member

Re: several questions about CCM's spec

Hope this will help you to calculate the total number of devices :

CreatePlease to create content