Abstract: Segment Identifier (SID) list compression includes receiving a calculated path in a Segment Routing network from a headend node to an end node; utilizing a compression approach to determine a segment list that, when expanded, matches the calculated path, wherein each segment in the segment list is identified by a SID, and wherein the SID is selected from any of a base topology in the Segment Routing network and any Flexible Algorithm (Flex-Algo) topologies in the Segment Routing network; and providing the segment list to the headend node. The SID list compression can further include, prior to the receiving, calculating the calculated path from the headend node to the end node based one or more constraints, wherein the SIDs are selected after the calculated path is determined without regard to any purpose of the any Flex-Algo topologies.

Abstract: Systems and methods for detecting segment expansion changes in Segment Routing using Dynamic Shortest Path First (SPF) include tracking one or more provisioned paths for one or more Segment Routing (SR) policies in a Segment Routing network, based on Shortest Path First (SPF) pairs associated with segments of the one or more provisioned paths; responsive to routing changes in the Segment Routing network, determining which of the SPF pairs are affected due to their SPF trees changing based on the routing changes; and determining which of the one or more SR policies have veered off of their respective provisioned path based on which of the SPF pairs are affected by the routing changes.

Abstract: Systems and methods for domain Border Router (BR) resiliency with segment compaction in Segment Routing include obtaining a compressed segment list for a calculated path in a Segment Routing network, wherein the Segment Routing network includes a plurality of domains with the calculated path being through at least two domains, wherein the compressed segment list includes a plurality of Segment Identifiers (SID) each SID identifying a segment, and wherein, when expanded, the compressed segment list matches the calculated path; analyzing the compressed segment list for any domain border routers between two domains of the at least two domains to determine associated anycast SID for the any domain border routers; and utilizing the associated anycast SID in the compressed SID list for resiliency between the two domains.

Abstract: Segment Identifier (SID) list compression includes receiving a calculated path in a Segment Routing network from a headend node to an end node; utilizing a compression approach to determine a segment list that, when expanded, matches the calculated path, wherein each segment in the segment list is identified by a SID, and wherein the SID is selected from any of a base topology in the Segment Routing network and any Flexible Algorithm (Flex-Algo) topologies in the Segment Routing network; and providing the segment list to the headend node. The SID list compression can further include, prior to the receiving, calculating the calculated path from the headend node to the end node based one or more constraints, wherein the SIDs are selected after the calculated path is determined without regard to any purpose of the any Flex-Algo topologies.

Abstract: A network control system is configured to manage controllable network elements or network paths through programmable rule-based engines operating at multiple scopes. A plurality of managed objects, including operator-intent objects such as Segment Routing (SR) policies and Traffic Engineering (TE) tunnels, and path-calculation objects such as managed paths, are maintained. Each rule-based engine is associated with a scope comprising at least an individual managed object scope, a set of related managed objects scope, and a network-wide scope. State information of the managed objects is monitored at each scope, and one or more customizable rules are applied to evaluate conditions based on the monitored state information. Responsive to the evaluations, the system performs fine-grained actions on individual managed objects and broad-scale actions across multiple managed objects within a common network control framework.

Abstract: A Constrained Shortest Path First (CSPF) path computation for an unordered list of included interfaces includes receiving a request for a shortest path in a network from a source to a destination; determining all possible path combinations between the source, the list of interfaces, and the destination, where each of the possible path combinations includes a plurality of sub-paths stitched together to form an end-to-end path between the source and the destination; for each of the possible path combinations, determining an end-to-end path from the source to the destination based on (1) utilizing an already computed sub-path if available, (2) computing a sub-path if it has not been computed yet and storing a result for re-use, and (3) rejecting a possible path combination based on one or more criteria; and responding to the request with a shortest path of all of the possible path combinations based on the metric.

Abstract: A Constrained Shortest Path First (CSPF) path computation for an unordered list of included interfaces includes receiving a request for a shortest path in a network from a source to a destination; determining all possible path combinations between the source, the list of interfaces, and the destination, where each of the possible path combinations includes a plurality of sub-paths stitched together to form an end-to-end path between the source and the destination; for each of the possible path combinations, determining an end-to-end path from the source to the destination based on (1) utilizing an already computed sub-path if available, (2) computing a sub-path if it has not been computed yet and storing a result for re-use, and (3) rejecting a possible path combination based on one or more criteria; and responding to the request with a shortest path of all of the possible path combinations based on the metric.

Abstract: Systems and methods for computing paths through a network are provided. A method, according to one implementation, includes the step of storing and managing a first set of objects including one or more Segment Routing (SR) policies and Traffic Engineering (TE) tunnels, where the first set of objects represents custom behavior received from a network operator for defining intended characteristics of traffic flowing through a network. The method also includes the step of storing and managing a second set of objects representing one or more managed paths through the network, where the managed paths are calculated by a TE technique using the one or more SR policies and TE tunnels.

Abstract: Systems and methods for k-shortest paths computation in Segment Routing considering segment depth include receiving a request for a path in a Segment Routing network from a first node to a second node with the path having a pruning criteria; determining a shortest path utilizing a Constrained Shortest Path First (CSPF) algorithm with a sorting criteria used as a metric in the CSPF algorithm; utilizing a modified Yen's algorithm to determine one or more additional paths based on diversions from the shortest path, wherein the modified Yen's algorithm explores the diversions based on the pruning criteria; and providing the shortest path and the one or more additional paths as a response to the request, each of the shortest path and the one or more additional paths pass the pruning criteria.

Abstract: Systems and methods for detecting segment expansion changes in Segment Routing using Dynamic Shortest Path First (SPF) include tracking one or more provisioned paths for one or more Segment Routing (SR) policies in a Segment Routing network, based on Shortest Path First (SPF) pairs associated with segments of the one or more provisioned paths; responsive to routing changes in the Segment Routing network, determining which of the SPF pairs are affected due to their SPF trees changing based on the routing changes; and determining which of the one or more SR policies have veered off of their respective provisioned path based on which of the SPF pairs are affected by the routing changes.

Abstract: Systems and methods for segment compaction in Segment Routing with resiliency to restoration include, responsive to a path having been computed in a Segment Routing network from a source node to a destination node, assuming all failed links in the Segment Routing network are temporarily restored; and determining a segment list, with all of the failed links assumed temporarily restored, that corresponds to the computed path, such as by preferring node segments over adjacency segments to match the computed path.

Abstract: Systems and methods for computing paths through a network are provided. A method, according to one implementation, includes the step of storing and managing a first set of objects including one or more Segment Routing (SR) policies and Traffic Engineering (TE) tunnels, where the first set of objects represents custom behavior received from a network operator for defining intended characteristics of traffic flowing through a network. The method also includes the step of storing and managing a second set of objects representing one or more managed paths through the network, where the managed paths are calculated by a TE technique using the one or more SR policies and TE tunnels.

Abstract: Systems and methods include receiving a request for a service in a Segment Routing network; determining an intended path for the service, provisioning a head-end node with a Segment Identifier (SID) list for the intended path, and reserving bandwidth for the service on the intended path; monitoring the Segment Routing network; and responsive to a condition determined based on the monitoring, updating the SID list for the service. The condition can include a current path for the service in the Segment Routing network differing from a provisioned path in the Segment Routing network. The condition can be based on any of a failure in the Segment Routing network, a topology change in the Segment Routing network, bandwidth changes in the Segment Routing network, an optimization timer, and input from an operator.

Abstract: Systems and methods include receiving a request for a service in a Segment Routing network; determining an intended path for the service, provisioning a head-end node with a Segment Identifier (SID) list for the intended path, and reserving bandwidth for the service on the intended path; monitoring the Segment Routing network; and responsive to a condition determined based on the monitoring, updating the SID list for the service. The condition can include a current path for the service in the Segment Routing network differing from a provisioned path in the Segment Routing network. The condition can be based on any of a failure in the Segment Routing network, a topology change in the Segment Routing network, bandwidth changes in the Segment Routing network, an optimization timer, and input from an operator.