The actual feature here is Logical Partitioning, of which Geolocations and Geolocation Filters are components.
This question is easier to answer intra-cluster first: LP will evaluate policy each time the call participants change. In the case of an ad-hoc conference, LP policy is evaluated for the consult leg and again when joining the additional call legs to the conference. For example:
1. An incoming call arrives on the Bangalore PRI and is answered by user in the Bangalore office. This is “Bangalore border to Bangalore interior” and is allowed.
2. The Bangalore user presses Conference and calls a Directory Number (ie another user within the Closed User Group of the company) in Sydney. This is “Bangalore interior to Sydney interior” and is allowed; you cannot block interior to interior calls.
3. The Bangalore user attempts to join the calling and consult call legs into a conference. This fails with the phone displaying “conference is unavailable” because “Bangalore border to Sydney interior” is not allowed.
This example assumes you configured LP policy to conform with India TRAI. I’m not saying LP must work this way; it’s up to you how you configure the policy rules.
By default, any trunk-side interface of CUCM is a border device: SIP Trunks, H.323 Gateways, and trunk-type interfaces of MGCP gateways such as FXO, T1 CAS, and ISDN. For SIP inter-cluster trunks between CUCM instances you can check the “send geolocation data” on the trunk. This will extend awareness of interior devices amongst clusters. For this to work you need to create Geolocations on all clusters and assign them to the applicable Device Pools. Without this the Geolocation of the receiving SIP ICT will be used.
