About transforms and search rules
The VCS can be configured to use transforms and search rules as a part of its call routing process.
Transforms are used to modify the alias in a search request if it matches certain criteria. You can transform
an alias by removing or replacing its prefix, suffix, or the entire string, and by the use of regular expressions.
This transformation can be applied to the alias at two points in the routing process: as a pre-search transform,
and as a zone transform.
Pre-search transforms are applied before any Call Policy or User Policy are applied and before the search
process is performed (see
Zone transforms are applied during the search process by each individual search rule as required. After
the search rule has matched an alias they can be used to change the target alias before the search request
is sent to a target zone or policy service (see
Search rules are used to route incoming search requests to the appropriate target zones (including the Local
Zone) or policy services.
The VCS's search rules are highly configurable. You can:
define alias, IP address and pattern matches to filter searches to specific zones or policy services
define the priority (order) in which the rules are applied and stop applying any lower-priority search rules
after a match is found; this lets you reduce the potential number of search requests sent out, and speed up
the search process
set up different rules according to the protocol (SIP or H.323) or the source of the query (such as the Local
Zone, or a specific zone or subzone)
limit the range of destinations or network services available to unauthenticated devices by making specific
search rules applicable to
use zone transforms to modify an alias before the query is sent to a target zone or policy service
Note that multiple search rules can refer to the same target zone or policy service. This means that you can
specify different sets of search criteria and zone transforms for each zone or policy service.
The VCS uses the protocol (SIP or H.323) of the incoming call when searching a zone for a given alias. If the
search is unsuccessful the VCS may then search the same zone again using the alternative protocol,
depending on where the search came from and the Interworking mode
If the request has come from a neighboring system and Interworking mode is set to Registered only, the
VCS searches the Local Zone using both protocols, and all other zones using the native protocol only
(because it will interwork the call only if one of the endpoints is locally registered).
If Interworking mode is set to On, or the request has come from a locally registered endpoint, the VCS
searches the Local Zone and all external zones using both protocols.
Cisco VCS Administrator Guide (X7.2)
About pre-search transforms
Search and zone transform process
Dial plan and call processing
for more details).
(VCS configuration > Protocols >
for more details).
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