Multiple redundancy schemes in an optical network

Abstract

Methods and apparatuses for multiple redundancy schemes in an optical network are described herein. In one embodiment, an exemplary method includes receiving a demand for allocating a first protection path that meets a first set of disjointness constraints with respect to a first working path according to a first protection scheme having a first priority, in response to the demand, locating a second protection path that meets a second set of disjointness constraints with respect to a second working path according to a second protection scheme having a second priority, and assigning the second protection path as a protection path to the first working path if the first priority of the first protection scheme is higher than the second priority of the second protection scheme. Other methods and apparatuses are also described.

1 . A method performed in an access node of a wave division multiplexing optical network, the method comprising:
 searching, in response to a demand for a protection path that meets a first set of disjointness constraints with respect to a first working path, in a database for a first protection path that meets the first set of disjointness constraints; and   if the first protection path cannot be located, searching for a second protection path that meets a second set of disjointness constraints and is currently assigned as a protection path for second working path, the second set of disjointness constraints being determined according to a disjointness preference order specified by an owner of the network.   
     
     
         2 . The method of  claim 1 , wherein the disjointness preference order comprises an order from the most preferred to the least preferred as of fully node disjointness, fully link disjointness, maximally node disjointness, and maximally link disjointness. 
     
     
         3 . The method of  claim 2 , wherein the second protection path is searched from the most preferred disjointness to the least preferred disjointness with respect to the working path. 
     
     
         4 . An apparatus, comprising:
 an access node, to be coupled in a wavelength division multiplexing optical network, including,
 a database to store a representation of available paths from the access node to reachable destinations, the available paths including one or more working paths protected by one or more protection paths, and 
 a routing module to
 search, in response to a demand for a protection path that meets a first set of disjointness constraints with respect to a first working path, in a database for a first protection path that meets the first set of disjointness constraints, and 
 if the first protection path cannot be located, search for a second protection path that meets a second set of disjointness constraints and is currently assigned as a protection path for second working path, the second set of disjointness constraints being determined according to a disjointness preference order specified by an owner of the network. 
 
   
     
     
         5 . The apparatus of  claim 4 , wherein the disjointness preference order comprises an order from the most preferred to the least preferred as of fully node disjointness, fully link disjointness, maximally node disjointness, and maximally link disjointness. 
     
     
         6 . The apparatus of  claim 5 , wherein the second protection path is searched from the most preferred disjointness to the least preferred disjointness with respect to the working path. 
     
     
         7 . A method performed in an access node of a wave division multiplexing optical network, the method comprising:
 receiving a demand for a first protection path associated with a first working path according to a first protection scheme having a first priority, and   preempting a second protection path that is a protection path of a second working path according to a second protection scheme having a second priority, if the first priority is higher than a second priority according to a protection scheme priority order specified by an owner of the network.   
     
     
         8 . The method of  claim 7 , wherein the protection scheme priority order comprise an order from high to low priorities as of 1+1, 1:1, 1:N, and reroutable. 
     
     
         9 . The method of  claim 7 , wherein the second protection path is searched and located according to the protection scheme priority order from low to high priorities. 
     
     
         10 . An apparatus, comprising:
 an access node, to be coupled in a wavelength division multiplexing optical network, including,
 a database to store a representation of available paths from the access node to reachable destinations, the available paths including one or more working paths protected by one or more protection paths, and 
 a routing module to
 receive a demand for a first protection path that is a protection path of a first working path according to a first protection scheme having a first priority, 
 preempt a second protection path associated with a second working path according to a second protection scheme having a second priority, if the first priority is higher than a second priority according to a protection scheme priority order specified by an owner of the network. 
 
   
     
     
         11 . The apparatus of  claim 10 , wherein the protection scheme priority order comprise an order from high to low priorities as of 1+1, 1:1, 1:N, and reroutable. 
     
     
         12 . The apparatus of  claim 10 , wherein the second protection path is searched and located according to the protection scheme priority order from low to high priorities.