Communication Manager 5.1 and later builds the AGL for each telephone during registration using the following parameters:
Communication Manager builds the AGL based on the C-LANs for the home region. For non-TTS and TTS telephones, the AGL is built using a random starting point in the network region C-LAN array. Communication Manager picks the administered number of C-LANs from that initial point, based on the number of C-LANs administered in the AGL field of the Inter Network Region Connection Management screen.
The system then builds the AGL based on the list of administered directly connected regions. The order of regions is selected by round robin method, and the C-LANs are selected based on the same random algorithm that is used for selecting C-LANs from the home region.
The system builds the AGL for indirectly connected regions in the same way as it does for directly connected network regions.
The difference in the Communication Manager enhancement of this feature is that the IP (H.323) telephone can now use C-LANs from all network regions as alternate gatekeepers, as long as they are connected (directly or indirectly) to the native region. The alternate gatekeepers are sent in the following order: in-region, directly connected regions, and indirectly connected regions.
