Cisco UserLookup Web service routes the commercial calls (calls through external gateways) to an alternate internal number of the called party in order to avoid the commercial cost of calling an external number.
If a caller within a Cisco Unified Communications Manager network makes a call on an external number, Cisco Unified Communications Manager checks if an internal number exists for the called party in the LDAP database. If an internal number exists, the call is routed to that internal number. If the internal number is not found in the LDAP database, the call is routed to the original (external) number.