Load balancing is a trunk deployment solution. You can configure trunk or call server entities. When the SIP trunk of one location is not running, the Load balancing feature distributes the SIP traffic to available SIP servers. Distributing the SIP traffic to available SIP servers increases the system throughput and scalability. Avaya SBC supports the following methods to distribute the SIP traffic to the cluster of SIP servers:
Priority
Round-Robin
Weighted Round-Robin
DNS SRV
Before routing the SIP traffic to the available SIP servers, Avaya SBC monitors the SIP server status and uses the server status information to exclude the unavailable SIP servers. To know the available servers information and to route the SIP traffic to the available SIP servers, Avaya SBC uses the Heartbeat feature configured on the server entity. Avaya SBC uses the time-of-day policy to select the entries that must be routed from the configured routing profile. Routing Profile has two criteria: URI Group and Time of Day.
You can add up to 20 next hop entries in each routing entry to load balance the SIP traffic.
Note:
Ensure that you perform all the steps of trunk server configuration for the primary and subsequent servers listed in the load balancing configuration.
Priority: The Request message takes first priority from the list of next hop addresses. If a message fails to reach the first next hop address, the message takes the next hop address that has second priority.
Round-Robin: If you configure 20 next hop addresses, then Avaya SBC sends the request message in the sequence that the IP addresses are configured.
Weighted Round-Robin: If you assign a weight for each hop address, the messages are sent based on the number of requests that each hop address can handle.
DNS SRV: If you selected the DNS SRV mechanism option, you cannot enter more than one domain name. You can enable or disable NAPTR. The system uses the DNS priority to route the message.
