Cisco Callmanager Partition and calling search spaces (CSS) explained!

Contributed by Al Banks  
Tagged: Cisco call manager  

Cisco CallManager partitions and calling search spaces (CSS) are confusing. This Tech-Recipe describes how I keep track of how this stuff works.

Partitions contain things, like phones, gateways, and route patterns.

CSS show which things can see other things.

For example,

Phone1 is in partition Phone1-P.
Route Pattern 911 is in partition Site1-911-P
Route Pattern 9.! is in partition Site1-Unrestricted-P.

CSS Site1-911 contains the Site1-911-P and Phone1-P partitions.
CSS Site1-UR contains the Site1-911-P, Phone1-P, and Site1-Unrestricted-P partitions.

When the Site1-911 CSS is applied to a directory number (DN), the dialed digits “911″ match the 911 route pattern, and the call is routed to the pattern’s gateway Gateway1. Other dialed digits won’t match any patterns, since the 9.! pattern is not in this CSS, and the call ends.

When the Site1-UR CSS is applied, the DN can dial any digits and find a match via the 9.! pattern.

NOTE: “!” is a pattern that matches all digits, regardless of length