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.