Cisco TelePresence Administrator's Manual page 133

Zones and neighbors
the directory VCS as a neighbor zone
n
a search rule with a Mode of Any alias and a Target of the directory VCS
n
There is no need to neighbor every VCS with each other. Adding a new VCS now only requires changing
configuration on the new VCS and the directory VCS. However, note that it may be necessary to neighbor
your VCSs to each other if you are using device authentication — see below for more information.
Also, failure of the directory VCS in this situation could cause significant disruption to communications.
Consideration should be given to the use of
H.323 calls and optimal call routing
For H.323 calls, if Optimal
Source of Any. If the Source is configured to All zones, H.323 calls will fail to connect. This is because the
H.323 SETUP message, having followed the optimized route established by the original LRQ or ARQ, will
appear to the target VCS as coming from an unknown zone. SIP calls, however, are successfully routed if
the search rule Source is All zones (because in SIP the search and call setup is combined into one
message).
Hierarchical dial plan (directory VCS) deployments and device authentication
See Hierarchical dial plans and authentication policy [p.115]
your authentication policy within a hierarchical dial plan.
Cisco VCS Administrator Guide (X8.1.1)
clustering
call routing is enabled you must ensure that all search rules are configured with a
for increased resilience.
for important information about how to configure
Structuring your dial plan
Page 133 of 507