Cisco Cisco Customer Voice Portal 8.0(1)

The current version of the Gatekeeper only allows the GKTMP interface to be “on” or “off.” That 
is, the Gatekeeper will either query a GKTMP server like the NAM for all calls, or none of the 
calls. This means that if GKTMP is desired for conditional routing into the ISN (recommended), 
it must also be used on all ISN lookups to the Gatekeeper for call transfers. However, this latter 
lookup is superfluous if the NAM/ICM is the GKTMP server, as the NAM has already made the 
routing decision by the time the ISN does a Gatekeeper lookup. In this case, the NAM would 
need to be configured to perform the equivalent of a “null” lookup for the ISN’s GKTMP 
queries.

If a Gatekeeper is present in an inbound routing configuration, you can minimize Gateway configuration. 
It is recommended that the Gateways be configured to always query the Gatekeeper for routing 
information. This may be done by specifying a wildcard dial-peer. 

For detailed instructions on how to configure wildcard dial-peers on Gateways, see the Cisco Internet 
Service Node (ISN) Configuration and Administration Guide.

Gateways not in the ISN zone must be configured to query their own zone Gatekeeper for routing 
information. The originating Gatekeeper will discover the ISN Zone Gatekeeper through an H.323 
Location Request (LRQ) message. The ISN Zone Gatekeeper will determine proper routing, which will 
be returned to the originating Gateway (by way of the originating Gatekeeper).

For performance reasons, it may be desirable to route inbound calls to the ISN node nearest to the 
originating Gateway. Aside from using the GKTMP interface, this can be accomplished by setting up 
separate H.323 Zones for the different ISN nodes. 

While H.323 requires each zone to be controlled by a single (logical) Gatekeeper, there is nothing to 
prevent multiple zones from being controlled by the same Gatekeeper. However, ISN Version 2.1 does 
not support multiple logical Gatekeepers on the same physical Gatekeeper machine. For ISN 2.1, 
multiple Gatekeepers must be implemented on separate Gatekeeper machines.

 shows ISN nodes and Gateways placed in three different H.323 zones:

ISN_Node1 and Gateway Huey are assigned to Zone 1, which is controlled by GK1.

ISN_Node2 and Gateway Dewey are assigned to Zone 2, which is controlled by GK2. 

ISN_Node3 and Gateway Louie are assigned to Zone 3, which is controlled by GK3.