SRND ? about CCM 4.X

Unanswered Question
Mar 26th, 2007

I am desiging a large enterprise IPT network. I have been working on CCM since the 2.4 days shortly after Cisco purchased the Selsius product. I have always used the rule of thumb that 500 sites is the limit for a single cluster. The other day I had an engineer tell me I am wrong. I know the technology changes but who is right. I have design two clusters for 814 sites with ICL to connect them. If a couple of you IPT vets tell me I am wrong I will bow down to the newbee.

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Chris Deren Mon, 03/26/2007 - 21:01

I would not necessarly look at the number of sites to determine number of clusters as sites may vary in size, and you may have a customer with 10 phones per site with no additional applicaions. I would rather look at the total number of devices in the cluters, number of GWs, extenal applications i.e. IPCC, etc.

Doing it for so long I am sure you know the limits, especially between the advertised marketing numbers and realistic environment CCM can handle.

I guess what I am trying to convey is not to set a hard coded number for sites, but analyze the whole environent instead.

Just my 2 cents.


dconstantino Tue, 03/27/2007 - 05:42

I guess when I think of sites I look at it from the voice gateways since each site will have SRST and and will be setup as a VG weather it be MGCP or H323.

The other issue I guess is Unity servers only supporting 3000 MB per server.

800 + sites seem like a lot of sites for one cluster to handle not only from size perspective but resources on the servers them selves.

It is only about 3000 - 4000 phones. I have done 3000 + user deployment with less sites like 30 or 100 sites. 800 makes me think a little more about what this solution can truly handle with one cluster.

dgahm Mon, 03/26/2007 - 21:27

The 4.1 IP Telephony SRND just says 30,000 SCCP phones max per cluster. The 4.1 IP Video Telephony SRND says 500 H323 endpoints and 30,000 SCCP video endpoints per cluster.

I don't recall ever seeing a max site number.

MARTIN STREULE Wed, 04/04/2007 - 06:22


500 locations is still what they say it's the limit.

Here some limits for CCM 4.x (source: PDI helpdesk)


What is the maximum number limitation in Cisco CallManager 4.x for


Calling Search Space

Call Pickup Groups


Hunt groups


Below are the details for the maximum number for CCM 4.x of

Partitions -- 2000

Calling Search Space -- 2000

Call Pickup Groups -- 1000

Locations -- 500

Hunt groups -- 1500



Alison A Thu, 05/29/2008 - 12:55

martin ,

do you know any limitation number of members/DN's per Call Pickup Groups ???



Tim Smith Fri, 06/06/2008 - 06:03


It's maximum 500 locations for CAC...

So if you had 1000 physical sites.. without CAC :) maybe you could get away with it! :)

But.. has anyone actually tried to add anymore than 500 locations?

I've also seen that PDI response with the 4.x limits.. some of them seem a bit low. I lodged another case to verify but I havent heard anything back.

Also there is some sort of additional Hunt Group limitation.. not the number of groups.. but the number of end points I think.

I vote Cisco should include maxmimum capacitiy of these things in the SRND! :)



MARTIN STREULE Fri, 06/06/2008 - 06:31


This are the limitations I am aware about:

Maximum number for CCM 4.x:

Partitions -- 2000

Calling Search Space -- 2000

Call Pickup Groups -- 1000

Locations -- 500

Hunt groups -- 1500

CCM 6.0 per cluster limitations:

Locations -- 1000 with 7845 server

Max. 1100 H323 devices (gateways, trunks, clients...)

Max. 1100 MGCP gateways

Max. 30'000 SCCP or SIP IP phones

The SRND actually contains some of this stuff. And there is PDI Helpdesk which can help with this.

Good luck, :-)



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