Using Zone Prefixes and
Gatekeeper Clusters for Redundancy
The zone prefix command does not allow you to list multiple destination gatekeepers.
Gatekeeper clusters avoid this limitation and allow gatekeepers to act in a
redundant manner.
In Figure 5.6, gk1 and gk2 can be grouped into a cluster. For example, gk1
and gk2 could both be defined in zone “zoneone” and cluster “cluster1.” Gk1
and gk2 would list the opposite gatekeeper as belonging to the cluster.They can
be configured to transfer calls to the alternate gatekeeper based on many parameters,
such as CPU or memory utilization. In this example, gk1 uses a limit of
100 active calls at which point calls are transferred to the alternate:
gatekeeper
zone local zoneone company.com
zone cluster local cluster1 zoneone
element gk2’s IP address
exit
load balance calls 100
The remote cluster (cluster1) and each of the gatekeepers in the cluster are
defined on gk3.Then the appropriate zone prefix is configured to use the cluster.
Continuing with this example, gk3 is configured with cluster “cluster1,” of which
gk1 and gk2 are both members. Gk3 is then configured to route calls for the 312
area code to cluster1:
gatekeeper
zone local zonetwo company.com
zone cluster remote cluster1 company.com
element gk1 gk1’s IP address
element gk2 gk2’s IP address
exit
zone prefix cluster1 312.......