Load balancing in Asterisk can be an overloaded term. In some cases, it refers to spreading calls to multiple servers. In others, it refers to calls made outbound. There are other cases as well. The two cases mentioned are two that are not handled by Asterisk out of the box, and additional software may need to be introduced in order to handle them. In multi-server Asterisk call center installs, load balancing allows calls to be distributed more evenly which prevents overloading any particular server.
One method to do this is employing a SIP proxy. The proxy should be configurable enough that it can make decisions about where the call should be directed in realtime while taking into account changing conditions on the server. For instance, if an Asterisk server becomes unavailable or overloaded, it should be possible to remove that server from the active list. Allowing outbound calls from multiple servers is also a must to avoid having to have a trunk for each Asterisk server.
Indosoft’s Q-Suite has a High Availability SIP proxy that combines these features along with an Overseer that monitors the health of each Asterisk server and alerts the SIP proxy of a server’s availability. Selection of servers can also be made on a per-trunk basis if needed. This intelligent SIP proxy also includes patented technology for call survival. These additional features provide a high availability Asterisk call center solution that’s suitable for a wide variety of applications.