Patent ID: 7848264

Claim:
A method for operating a router, comprising: executing a spanning tree protocol to select a first port as a root port and to select a second port as a designated port and to place both the root port and the designated port in a forwarding state, the root port for communication with a root router and the designated port to communicate with at least one router in a lower leaf of a spanning tree established by executing the spanning tree protocol; selecting a third port as a back-up designated port and placing the back-up designated port in a blocked state; detecting a link failure; transitioning by the spanning tree protocol, in response to detecting the failure, the designated port into the blocked state and the back-up designated port into the forwarding state, without the spanning tree protocol transitioning the back-up designated port through any intermediary states in moving from the blocked state to the forwarding state; and transmitting, by the back-up designated port, one or more messages, the messages to tell devices downstream in the spanning tree that the router has a new designated port.