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.