Providing high availability in a software defined network

A non-transitory computer-readable medium storing instructions which, when executed by a processor of a standby software defined networking controller, cause the processor to perform operations, the operations comprising:

• detecting when a number of path computation client sessions reported by an active software defined networking controller fails to match an expected number;
• verifying, after expiration of a predefined delay implemented after the detecting, that the number of path computation client sessions reported by the active software defined networking controller still fails to match the expected number;
• and
• assuming, after the verifying, a role of the active software defined networking controller.

A device comprising:

• a processor;
• and
• a computer-readable medium storing instructions which, when executed by the processor, cause the processor to perform operations, the operations comprising:
• detecting when a number of path computation client sessions reported by an active software defined networking controller fails to match an expected number;
• verifying, after expiration of a predefined delay implemented after the detecting, that the number of path computation client sessions reported by the active software defined networking controller still fails to match the expected number;
• and
• assuming, after the verifying, a role of the active software defined networking controller.