Cisco TelePresence Administrator's Manual page 150

some peer-specific configuration items
n
user account details (when running in TMS Agent legacy mode)
n
You may need to wait up to one minute before changes are updated across all peers in the cluster.
Secure communication between peers
The VCS uses IPsec (Internet Protocol Security) to enable secure communication between each cluster
peer. Authentication is carried out through the use of a pre-shared access key.
Each peer in the cluster must be individually configured with the IP address and associated access key of
every other peer in that cluster.
Alternates
"Alternate" is an H.323 term for a system used to provide redundancy to a Primary gatekeeper. Prior to
version X3.0 the VCS supported Alternates, where the configuration would comprise a single active VCS
with additional unused alternate VCSs on standby. From X3.0 onwards, redundancy (along with other
features) is provided by clusters of peers. Peers support both H.323 and SIP and all peers can take
registrations and calls. For H.323 the Alternates returned in a Registration Confirm message list all the peers
in the cluster. Also note that some versions of TMS refer to peers as "members".
Cisco VCS Administrator Guide (X7.2)
Clustering and peers
Page 150 of 498