Cisco Cisco Customer Voice Portal 8.0(1)

If a Voice Browser indicates Resource Unavailability, the GK will move that Voice Browser to 
the bottom of its routing priority lists. (This means the GK can still route calls there, if higher 
priority targets go out of service). 

If the Voice Browser later indicates Resource Availability, the GK will place it back at the 
priority listed in the zone prefix command. 

Re-Queries. Gateways can be configured to re-query the Gatekeeper if the target Voice Browser 
(plus any alternates) does not properly respond to call setup. If the target Voice Browser goes out of 
service during the time period between the original GK query and the re-query (because either the 
Voice Browser has failed to re-register during the keep-alive period or the Voice Browser has 
unregistered with a URQ message), then the re-query can return a different target Voice Browser.

The time period between the original query and the re-query is short, so there may be limited 
benefit to re-queries

Technology Prefix. A Gatekeeper requires all Gateways (including the CVP Voice Browsers) to 
register with a Tech Prefix, where the Tech prefix precedes the dialed number and is simply a 
number followed by the # sign. (By default, the CVP Voice Browsers all register with the Tech Prefix 
2#.) 

All Gateways in an H.323 zone of a given type (for example, all Voice Browsers) register with the 
Gatekeeper with the same Tech Prefix; the Gateways prepend it to the dialed number that they pass 
to the Gatekeeper. The Gatekeeper is configured to recognize the Tech Prefix and associate it with 
a list of Gateways. Once the tech prefix association is made, the Gatekeeper uses its zone prefix 
configuration to determine which associated Voice Browser to route the call to. After the Gatekeeper 
indicates the target Voice Browser to the querying Gateway, the Gateway prepends the same tech 
prefix to the dialed number it passes to the target Voice Browser during H.323 call setup. The Voice 
Browser strips off the tech prefix before passing the dialed number to the CVP Application Server 
for further processing.

There is a situation where an CVP Voice Browser would register with the 1# tech-prefix. That 
situation is as follows: If the CVP Voice Browser is a Type 2 VRU (target of an ICM translation 
route) and the switch that is directing the call to it is itself an CVP Voice Browser, then the Type 2 
Voice Browser must be tech-prefix 1#. By default, CVP Voice Browsers register as 2# for inbound 
call routing. This value would need to be adjusted via the Voice Browser CLI after installation. The 
reason is that unlike a gateway, the Voice Browser routing the call cannot prepend a tech-prefix to 
the called-number. Therefore the gatekeeper must choose from endpoints that are registered in its 
default technology prefix (1#).

GKTMP Option. A Gatekeeper can query another server for routing information using the 
Gatekeeper Transaction Message Protocol (GKTMP). The GKTMP is a RAS-like protocol that gives 
an external application like the NAM/ICM the ability to override Gatekeeper behavior. GKTMP can 
be used to perform conditional routing to the CVP Voice Browsers. For example: 

If an agent is available, do not route the call to the CVP; route it directly to the agent. 

If today is Monday, do not route calls to the CVP. 

Route the Inbound call to an CVP Voice Browser nearest to the originating Gateway.