Patent ID: 8427940

Claim:
An apparatus comprising: a first segment endpoint bridge (SEB) configured to couple to a second SEB via a plurality of path segments comprising a working segment and a plurality of candidate protection segments; a 1:1 protection state machine, configured to switch traffic from the working segment to an active protection segment in the case of detecting failure of the working segment; a protection segment selection (PSS) state machine, configured to select a protection segment, from a plurality of candidate protection segments, as the active protection segment for the working protection segment; wherein a protection segment that is operational and has a highest priority is selected as the active protection segment from the plurality of candidate protection segments, if the active protection segment fails, another candidate protection segment which has a next highest priority and is operational is selected as the active protection segment instead of the failed active protection segment from the plurality of candidate protection segments; wherein the combination of the 1:1 protection state machine and the PSS state machine provides a M-for-one (M:1) protection function for the first SEB and the second SEB, where M is the quantity of the candidate protection segments; wherein one first state variable is used to maintain each of the candidate protection segments, a plurality of second state variables are used to maintain each of the working segment and the active protection segment; and wherein the 1:1 protection state machine is supported by the second state variables for each of the working segment and the active protection segment, and wherein the PSS state machine is supported by the one first state variable for each of the candidate protection segments; wherein the second state variables comprise a Signal Fail (SF) variable, a Signal Fail Hold-Off (SFH) variable, a Lockout of Protection (LoP) variable, a Forced Switch (FS) variable, an MStProtection (MStP) variable, and an MStWorking (MStW) variable, and wherein the first state variable comprises a SF variable for each port associated with each of the candidate protection segments.