Patent ID: 7894334

Claim:
A method for hierarchical redundancy in a distributed control plane of a network element, wherein the distributed control plane includes a plurality of control plane process instances instantiated onto a plurality of processing entities including a primary active processing entity and a plurality of secondary processing entities, the method comprising: registering the plurality of processing entities with an application redundancy manager (ARM) instantiated on the primary processing entity; for each of the secondary processing entities, the ARM selecting one of the plurality of secondary processing entities to act as a backup for another one of the plurality of secondary processing entities, and the ARM causing its control plane process information to be synchronized between those secondary processing entities; collecting redundancy management information from each of the secondary processing entities; responsive to detecting a failure of one of the secondary processing entities, performing the following: determining, using the collected redundancy management information, which one or more of the plurality of secondary processing entities is backing up the failed secondary processing entity, and transitioning the one or more of the plurality of secondary processing entities backing up the failed secondary processing entity to an active state for the backed up control plane process information of the failed secondary processing entity; detecting an addition of another secondary processing entity to the distributed control plane; selectively distributing control plane process instances to the added secondary processing entity; and the ARM selecting one of the plurality of secondary processing entities to act as a backup for the added secondary processing entity, and selecting one of the plurality of secondary processing entities for the added secondary processing entity to backup.