13 High Availability Nodes

SBCs can be deployed in pairs to deliver high availability (HA). Two SBCs operating in this way are called an HA node. Over the HA node, media and call state are shared, keeping sessions/calls from being dropped in the event of a failure.

Two SBCs work together in an HA node, one in active mode and one in standby mode.

• The active SBC checks itself for internal process and IP connectivity issues. If it detects that it is experiencing certain faults, it will hand over its role as the active system to the standby SBC in the node.
• The standby SBC is the backup system, fully synchronized with active SBCs session status. The standby SBC monitors the status of the active system so that, if needed, it can assume the active role without the active system having to instruct it to do so. If the standby system takes over the active role, it notifies network management using an SNMP trap.

In addition to providing instructions for how to configure HA nodes and their features, this chapter explains how to configure special parameters to support HA for all protocols.