Abstract: A head-end node in a Segment Routing network includes circuitry configured to detect a failure of a Segment Routing policy, set an eligibility flag for the candidate path associated with the Segment Routing policy to false, and, if one or more other candidate paths exist for the Segment Routing policy, switch to another candidate path of the one or more other candidate paths considering corresponding eligibility flags for the one or more other candidate paths. The eligibility flag and the corresponding eligibility flags are maintained by the head-end node for the candidate path and the one or more other candidate paths such that the head-end node selects a path based thereon.

Abstract: Systems and methods implemented in a network element in a Segment Routing network include, for a service having two or more candidate paths and responsive to a failure on a current candidate path of the two or more candidate paths, setting an eligibility flag for the current candidate path; and selecting another candidate path of the two or more candidate paths, for the service, based on their eligibility flag.

Abstract: A method implemented in a Path Computation Element (PCE) or Software Defined Networking (SDN) controller includes computing a path for a service in a Segment Routing network where the path includes an explicit list of routers in the Segment Routing network; determining a Segment Identifier (SID) list for the path; an signaling the explicit list and the SID list to a head-end router for the service. The SID list can be compressed where it does not include a SID for each of the routers in the explicit. The method can further include monitoring Traffic Engineering characteristics in the Segment Routing network based on knowing the service is on the explicit list of routers.

Abstract: A method implemented in a network element includes, for a service, receiving a Segment Identifier (SID) list and an explicit list for an intended path in a Segment Routing network; expanding the SID list and comparing the expanded SID list to the explicit list; and setting the intended path as either valid or invalid based on the comparing. The intended path can be a primary path, and the steps can further include receiving a SID list and an explicit list for a backup path in the Segment Routing network. The steps can further include switching to the backup path responsive to a failure on the primary path, and switching back to the primary path responsive to it being valid.

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 implemented in a network element in a Segment Routing network include, for a service having two or more candidate paths and responsive to a failure on a current candidate path of the two or more candidate paths, setting an eligibility flag for the current candidate path; and selecting another candidate path of the two or more candidate paths, for the service, based on their eligibility flag.

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: A method implemented in a network element includes, for a service, receiving a Segment Identifier (SID) list and an explicit list for an intended path in a Segment Routing network; expanding the SID list and comparing the expanded SID list to the explicit list; and setting the intended path as either valid or invalid based on the comparing. The intended path can be a primary path, and the steps can further include receiving a SID list and an explicit list for a backup path in the Segment Routing network. The steps can further include switching to the backup path responsive to a failure on the primary path, and switching back to the primary path responsive to it being valid.

Abstract: Systems and methods for permitted network risks in diverse route determinations introduce the concept of permitted network risks which are risks that may be present in a disjoint path calculation. This removes the binary logic in conventional shared risk path determination, i.e., either exclude or include. With the present disclosure, a network risk may be excluded (must never use) or shared (may use if needed). In an embodiment, if a route for a backup tunnel or path excluding all network risks is not possible, then a route for the backup tunnel or path may be found excluding some network risks of the primary tunnel or path except specified network risks that are determined/specified as permitted network risks. Such permitted network risks can be explicitly specified by a network operator or implicitly determined based on a category (e.g., node and/or equipment may be shared network risks whereas links may not).

Abstract: Shared risk representation in networks for troubleshooting, assignment, and propagation across layers includes obtaining a configuration for a format to represent shared risks in a network; assigning a value to a plurality of shared risks in the network utilizing the format and utilizing a plurality of assignment techniques including automatic assignment and manual assignment; propagating the assigned values of the plurality of shared risks across one or more layers in the network; and storing the assigned values for use in path computation in the network.

Abstract: Shared risk representation in networks for troubleshooting, assignment, and propagation across layers includes obtaining a configuration for a format to represent shared risks in a network; assigning a value to a plurality of shared risks in the network utilizing the format and utilizing a plurality of assignment techniques including automatic assignment and manual assignment; propagating the assigned values of the plurality of shared risks across one or more layers in the network; and storing the assigned values for use in path computation in the network.

Abstract: Systems and methods for permitted network risks in diverse route determinations introduce the concept of permitted network risks which are risks that may be present in a disjoint path calculation. This removes the binary logic in conventional shared risk path determination, i.e., either exclude or include. With the present disclosure, a network risk may be excluded (must never use) or shared (may use if needed). In an embodiment, if a route for a backup tunnel or path excluding all network risks is not possible, then a route for the backup tunnel or path may be found excluding some network risks of the primary tunnel or path except specified network risks that are determined/specified as permitted network risks. Such permitted network risks can be explicitly specified by a network operator or implicitly determined based on a category (e.g., node and/or equipment may be shared network risks whereas links may not).

Abstract: A method for connecting endpoints. The method may include determining, using a first group of software threads, cross-connection information regarding various cross-connections among various network elements. The network elements may include a first network element and a second network element. The method may further include determining, using the first group of software threads, link information regarding various links between the network elements. The method may further include processing, within a network cache, the cross-connection information and the link information into various network resources groups. Each network resource group of the network resources groups may describe adjacent cross-connections for a link among the links.

Abstract: A method for connecting endpoints. The method may include determining, using a first group of software threads, cross-connection information regarding various cross-connections among various network elements. The network elements may include a first network element and a second network element. The method may further include determining, using the first group of software threads, link information regarding various links between the network elements. The method may further include processing, within a network cache, the cross-connection information and the link information into various network resources groups. Each network resource group of the network resources groups may describe adjacent cross-connections for a link among the links.