Patent ID: 8345542
Filing Date: 2013-01-01
Classification: H04L

Abstract:
1. An apparatus comprising: a first segment endpoint bridge (SEB) configured to couple to a second SEB via a plurality of path segments; wherein the path segments comprise a working segment and a plurality of candidate protection segments; wherein the candidate protection segments comprise a protection segment that is configured to protect the working segment; wherein the candidate protection segments other than the protection segment do not protect the working segment when the protection segment protects the working segment; wherein the first SEB comprises one or more state tables; wherein only one first state variable is used in the state tables to maintain each of the candidate protection segments other than the protection segment; a plurality of second state variables are used in the state tables to maintain each of the working segment and the protection segment; wherein the protection segment has a highest priority among the operational candidate protection segments as determined by a protection segment selection (PSS) state machine; wherein the working segment is protected by the protection segment using a one-for-one (1:1) protection state machine; wherein the PSS state machine provides the protection segment, to the 1:1 state machine, and 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; wherein M is the quantity of the candidate protection segments; wherein the 1:1 protection state machine is supported by the second state variables for each of the working segment and the protection segment, and wherein the PSS state machine is supported by the first state variable for each of the candidate protection segments; and 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.