Non-TTS telephones are load balanced at registration using the gatekeeper confirm (GCF) message. Each region has a list of available C-LANs or PE, and Communication Manager selects the commonly available C-LAN within the IP (H.323) telephone home network region. If there are C-LANs in that network region, the system uses load balancing techniques based on C-LAN priority, and available sockets. If all C-LANs are busy (none of the C-LANs are in service, or all C-LANS that are in service have used all the 480 available sockets), Communication Manager moves to directly connected network regions. The system checks all directly connected regions beginning with network region 1. All indirect network regions are used if there are no C-LANs administered in the IP telephone’s home network region, or directly connected network regions. The system also checks indirect network regions beginning with network region 1.
With the enhanced implementation of load balancing for non-TTS telephones feature, the system gives preference to the home region C-LANs, followed by the direct network region C-LANs, and indirect network region C-LANs. Indirect network region C-LANs are administered using the new AGL field on the Inter Network Region Connection Management screen. Any C-LAN within an eligible region may be assigned for load balancing. Within a specific region, the system selects the least loaded C-LAN, unless all C-LANs have reached their limit.
Load balancing for non-TTS telephones is based on the C-LAN received in GCF. Non-TTS telephones use this C-LAN to initiate a registration request (RRQ), and establish a socket to Communication Manager after completing Registration Admission Status (RAS).
Socket load balancing for TTS telephones occurs after registration is complete and AGL has been formed. Communication Manager initiates socket establishment to TTS telephones. Load balancing occurs across the C-LANs that were sent in AGL. Direct network regions and indirect network region C-LANs are considered as two groups.
When sending the AGL list with the administrable AGL feature, the system uses each network region (home, direct, indirect) and sends a subset of the C-LANs starting at a random place in the C-LAN array.
