When migration from On-premise Call Control Cisco Unified CM to Webex Calling, you can facing a situation where some users are registered to Webex Calling while others in the same location are registered to the On-premise Cisco Unified CM. In this coexistence of both cloud/on-premises solutions, in order to keep user experience not impacted you want to preserve the intra-site dialing habits so that for example users can continu to use the dialing format 4 digits even if the site or the location is partially migrated to Webex Calling. There is a cool feature on Webex Calling Control Hub called "Route Unknown Extensions to the Premises as Internal Calls". To enable the option, edit the location the users belong to and navigate to "Internal Dialing" section.
When enabled, any calls from Webex Users in this location to unknown extension (same digit as internal extension) are routed as "Premises Calls" to the Trunk to the CUBE in this location or the Route Group that includes this trunk you associed to this option.
For example when a Webex User with extension 1001 dials the Directory Number of Jabber User 2001, the call signaling is sent to Webex Calling, since the dialed number 2001 is not a Webex Calling Extension (there is no user on Webex Calling provisioned with 2001) and no match in the Dial Plans. The option "Route Unknown Extensions to the Premises as Internal Calls" instructs Webex Calling to route any extension with 2-6 digits to the Trunk or Route Group associated to it. If disabled the call is blocked.
When enabled, any calls from Webex Users in this location to unknown extension (same digit as internal extension) are routed as "Premises Calls" to the Trunk to the CUBE in this location or the Route Group that includes this trunk you associed to this option.
For example when a Webex User with extension 1001 dials the Directory Number of Jabber User 2001, the call signaling is sent to Webex Calling, since the dialed number 2001 is not a Webex Calling Extension (there is no user on Webex Calling provisioned with 2001) and no match in the Dial Plans. The option "Route Unknown Extensions to the Premises as Internal Calls" instructs Webex Calling to route any extension with 2-6 digits to the Trunk or Route Group associated to it. If disabled the call is blocked.
