Path recovery on failure in load balancing switch protocols

摘要

A method for managing multiple active paths among a plurality of network switches to identify and select an alternate path in response to failure of a path from a switch to a device. Load balancing protocols of the present invention enable the simultaneous use of multiple paths between network devices through a mesh of compliant network switches. When a port of a network switch fails (or the link connected to a port fails), a switch in accordance with the present invention selects an alternate port which may be used for forwarding packets to devices normally reached through the failed port. Networks switches operable in accordance with the structures and protocols of the present invention exchange messages to identify potential alternate paths. A potential alternate path is used to send a query message to a neighboring network switch to determine if a path to the identified devices is available through the neighboring network switch. Such query messages are propagated through all intermediate network switches between the switch sensing the failed port up to the identified network device. Acknowledgment messages are returned to verify potential availability of an alternate path. Where an intermediate network switch determines that the complete path is not available through it to the identified device, or where a potentially better path exists, a regenerated query message so indicating is returned along the path that initiated the query message.