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Number of Susbcribers/ CCM Service in a cluster

Below is an extract from the latest CCM book

"A CUCM cluster can have up to 20 servers in it. Only one publisher server is allowed in the cluster. The publisher houses the read/write copy of the database. Up to eight subscriber servers can be in the cluster, with the restriction that only four of the subscriber servers can perform active call processing. If more than four subscriber servers are used in a cluster, the additional servers are dedicated standby servers in case the active subscriber server is not available. The other 11 servers in the cluster can be responsible for various services, including TFTP and media resources (conferencing, music on hold, transcoding)"

I always thought you can have 8 x servers running CCM Service in a single Cluster, has this changed with 5.x, 6.x ? or is it just referencing a 1:1 redundancy model i.e 4 active servers with a redundant server for each active one

many thanks

Cisco Employee

Re: Number of Susbcribers/ CCM Service in a cluster

SRND has most of the times the answer:

With Cisco Unified CM 6.x, a cluster may contain as many as 20 servers, of which a maximum of eight may run the Cisco CallManager Service that provides call processing. The other servers may be configured as a dedicated database publisher, dedicated Trivial File Transfer Protocol (TFTP) server, or music on hold (MoH) servers. Media streaming applications (conference bridge or media termination point) may also be enabled on a separate server that registers with the cluster.

Unified CM Cluster Services



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