US Patent 11785077 Active-active standby for real-time telephony traffic

Active-active standby is maintained for communication sessions using session initiation protocol (SIP) processes between two active session zones in a first datacenter and a standby session zone in a second datacenter. In the event of a failure at a first active session zone at the first datacenter, a failover to the second active session zone at the first datacenter is performed such that there are no interruptions in the active sessions. In the event of a failure at both active session zones at the first datacenter, a failover to the second datacenter is performed.