Cisco Cisco TelePresence Video Communication Server Expressway 관리 매뉴얼

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D14049.08 
November 2010

Grey Headline (continued)

CISCO TELEPRESENCE

 VIDEO COMMUNICATION SERVER

ADMINISTRATOR GUIDE

Clustering overview

A VCS can be part of a cluster of up to six VCSs. Each VCS in the cluster is a peer of every other 
VCS in the cluster. Clusters are used to:

• 

increase the capacity of your VCS deployment compared with a single VCS

• 

provide redundancy in the rare case that a VCS becomes unavailable (for example, due to a 
network or power outage).

Peers have identical configuration, and share information with each other about their use of 
bandwidth, registrations, and FindMe users. This allows the cluster to act as one large VCS Local 
Zone.
The diagram opposite shows two separate clusters, both being monitored by Cisco TMS.

About the configuration master

All peers in a cluster must be configured identically for subzones, zones, links, pipes, 
authentication, bandwidth control and call policy. To achieve this, you define a cluster name and 
nominate one peer as the configuration master. Approximately every minute, all the other peers in 
the cluster request updated configuration information from the master, and overwrite their existing 
configuration with these new settings. 

”Alternate” is an H.323 term for a system used to provide redundancy to a Primary 
gatekeeper, and prior to version X3.0 the VCS supported Alternates. From X3.0 onwards, 
redundancy (along with other features) is provided by clusters of peers, which support both 

H.323 and SIP and work as equals. However, peers may sometimes be referred to as Alternates. 
Also note that some versions of Cisco TMS refer to peers as "members".

About clustering