Abstract: A method comprising identifying a physical ring in a physical layer of a network according to a logical ring in a logical layer of the network, wherein the logical ring is formed from a plurality of nodes interconnected by a plurality of logical links, and wherein the physical ring is formed from at least the plurality of nodes interconnected by a first plurality of physical links, computing a plurality of cross cord paths across the physical ring, and mapping the logical ring onto the physical layer to provide dual physical link failure survivability by determining primary paths and secondary paths for the plurality of logical links over the physical ring and the plurality of cross cord paths such that a secondary path of a first of the plurality of logical links is non-overlapping with a primary path of a second of the plurality of logical links.

Abstract: A method comprising identifying a physical ring in a physical layer of a network according to a logical ring in a logical layer of the network, wherein the logical ring is formed from a plurality of nodes interconnected by a plurality of logical links, and wherein the physical ring is formed from at least the plurality of nodes interconnected by a first plurality of physical links, computing a plurality of cross cord paths across the physical ring, and mapping the logical ring onto the physical layer to provide dual physical link failure survivability by determining primary paths and secondary paths for the plurality of logical links over the physical ring and the plurality of cross cord paths such that a secondary path of a first of the plurality of logical links is non-overlapping with a primary path of a second of the plurality of logical links.

Abstract: A method and apparatus are provided for enabling spare capacity allocation (SCA) in a network for protecting against dual link failures using a successive survivable routing (SSR) algorithm that has better scalability and shorter computation time than other techniques. An embodiment method implemented by an apparatus includes computing the SCA for a plurality of flows in the network for a plurality of primary backup paths and a plurality of secondary backup paths corresponding to a plurality of working paths for the flows using a SSR algorithm. Another embodiment method includes computing the SCA for each of a plurality of flows in the network for a plurality of primary backup paths and a plurality of secondary backup paths corresponding to a plurality of working paths for the flows using a SSR algorithm, and aggregating the computed SCA for the primary backup paths and the secondary backup paths for all the flows.

Abstract: A method for protecting a bi-connected network against a dual link failure, the method comprising finding a plurality of cut-pairs for a data flow, finding a work path and a primary backup path for the data flow, determining the cut-pairs that overlap both the work path and the primary backup path, merging the cut-pairs that overlap the work path and the primary backup path into a plurality of cut-groups, wherein each cut-group comprises a first half and a second half, and constructing a plurality of partially disjoint backup paths based on the cut-groups, wherein one of the partially disjoint backup paths protects against the dual link failure that causes a failure on the second half of a first cut-group and a failure on the first half of a second cut-group.

Abstract: A method implemented by an apparatus for providing spare capacity allocation (SCA) for dual link failures in a network. The SCA scheme computes the SCA for each of a plurality of flows in the network for a plurality of primary backup paths corresponding to a plurality of disjoint working paths for the flows using a first integer linear programming (ILP) model. The SCA scheme further computes the SCA for each of the flows for a plurality of secondary backup paths corresponding to the disjoint working paths and the primary backup paths using a second ILP model and the computed spare capacity information for the primary backup paths. The SCA scheme further aggregates the computed SCA for the primary backup paths and the secondary backup paths for all the flows.

Abstract: System and method embodiments are provided herein to obtain minimum or optimal spare capacity allocation (SCA) using partial disjoint paths (PDP) for bi-connected network topology. Both an integer linear programming (ILP) optimization model and an approximation algorithm, referred to herein as Successive Survivable Routing (SSR), are formulated for resolving the SCA with PDP. The embodiments include assigning a working path and a primary backup path on two disjoint routes between two end nodes, and assigning a plurality of secondary backup paths that are partially disjoint and that each pass through one fiber cut group on one of the two disjoint routes and all remaining fiber cut groups on the other one of the two disjoint routes. Each of the fiber cut groups includes all fiber cut pairs on both disjoint routes that have the same effect of interrupting a flow on both disjoint routes.

Abstract: A method and apparatus are provided for enabling spare capacity allocation (SCA) in a network for protecting against dual link failures using a successive survivable routing (SSR) algorithm that has better scalability and shorter computation time than other techniques. An embodiment method implemented by an apparatus includes computing the SCA for a plurality of flows in the network for a plurality of primary backup paths and a plurality of secondary backup paths corresponding to a plurality of working paths for the flows using a SSR algorithm. Another embodiment method includes computing the SCA for each of a plurality of flows in the network for a plurality of primary backup paths and a plurality of secondary backup paths corresponding to a plurality of working paths for the flows using a SSR algorithm, and aggregating the computed SCA for the primary backup paths and the secondary backup paths for all the flows.

Abstract: System and method embodiments are provided herein to obtain minimum or optimal spare capacity allocation (SCA) using partial disjoint paths (PDP) for bi-connected network topology. Both an integer linear programming (ILP) optimization model and an approximation algorithm, referred to herein as Successive Survivable Routing (SSR), are formulated for resolving the SCA with PDP. The embodiments include assigning a working path and a primary backup path on two disjoint routes between two end nodes, and assigning a plurality of secondary backup paths that are partially disjoint and that each pass through one fiber cut group on one of the two disjoint routes and all remaining fiber cut groups on the other one of the two disjoint routes. Each of the fiber cut groups includes all fiber cut pairs on both disjoint routes that have the same effect of interrupting a flow on both disjoint routes.

Abstract: A method for protecting a bi-connected network against a dual link failure, the method comprising finding a plurality of cut-pairs for a data flow, finding a work path and a primary backup path for the data flow, determining the cut-pairs that overlap both the work path and the primary backup path, merging the cut-pairs that overlap the work path and the primary backup path into a plurality of cut-groups, wherein each cut-group comprises a first half and a second half, and constructing a plurality of partially disjoint backup paths based on the cut-groups, wherein one of the partially disjoint backup paths protects against the dual link failure that causes a failure on the second half of a first cut-group and a failure on the first half of a second cut-group.

Abstract: A method implemented by an apparatus for providing spare capacity allocation (SCA) for dual link failures in a network, comprising computing the SCA for each of a plurality of flows in the network for a plurality of primary backup paths corresponding to a plurality of disjoint working paths for the flows using a first integer linear programming (ILP) model, computing the SCA for each of the flows for a plurality of secondary backup paths corresponding to the disjoint working paths and the primary backup paths using a second ILP model and the computed spare capacity information for the primary backup paths, and aggregating the computed SCA for the primary backup paths and the secondary backup paths for all the flows.