Abstract: A flexible-algorithm routing method comprises: receiving, by a first router, a route advertisement including a base node label, for a second router, associated with a segment routing path without flexible-algorithm, wherein the second router participates in a flexible-algorithm; deducing, by the first router and from the base node label, a node label, for the second router, associated with a segment routing path with the flexible-algorithm; and constructing, by the first router, a label stack including the node label for the second router to steer a packet to the second router via the segment routing path with the flexible-algorithm.

Abstract: A flexible-algorithm routing method comprises: receiving, by a first router, a route advertisement including a base node label, for a second router, associated with a segment routing path without flexible-algorithm, wherein the second router participates in a flexible-algorithm; deducing, by the first router and from the base node label, a node label, for the second router, associated with a segment routing path with the flexible-algorithm; and constructing, by the first router, a label stack including the node label for the second router to steer a packet to the second router via the segment routing path with the flexible-algorithm.

Abstract: Techniques are described for inter-domain segment routing using transport endpoint segments. A transport endpoint segment provisioned on a router within a domain represents any intra-domain tunnel originated at the router and having reachability to an indicated endpoint within the same domain. The provisioning router advertises a transport endpoint segment identifier (TESID) for the transport endpoint segment to other routers or a controller for use in segment routing. The TESID for the transport endpoint segment remains constant regardless of which intra-domain tunnel is bound to the transport endpoint segment. The provisioning router dynamically binds the transport endpoint segment to at least one intra-domain tunnel, and any changes to the bound intra-domain tunnel are updated locally at the provisioning router. In this way, an inter-domain segment routing tunnel may be constructed as a list TESIDs that are not affected by intra-domain tunnel changes.

Abstract: Techniques are described for inter-domain segment routing using transport endpoint segments. A transport endpoint segment provisioned on a router within a domain represents any intra-domain tunnel originated at the router and having reachability to an indicated endpoint within the same domain. The provisioning router advertises a transport endpoint segment identifier (TESID) for the transport endpoint segment to other routers or a controller for use in segment routing. The TESID for the transport endpoint segment remains constant regardless of which intra-domain tunnel is bound to the transport endpoint segment. The provisioning router dynamically binds the transport endpoint segment to at least one intra-domain tunnel, and any changes to the bound intra-domain tunnel are updated locally at the provisioning router. In this way, an inter-domain segment routing tunnel may be constructed as a list TESIDs that are not affected by intra-domain tunnel changes.

Abstract: The use and processing of update messages (e.g., BGP UPDATEs) that bind (e.g., MPLS) labels to address prefixes is improved such that labels are used more efficiently, and/or such that such update messages can be processed more efficiently. A distance vector control signaling protocol (e.g., BGP) peer device receives a control plane message (e.g., BGP Update) from a downstream peer device, the control plane message including (1) a network address of the downstream device as a next hop value, (2) a prefix value, and (3) at least one label associated with the prefix value. Responsive to receiving the control plane message, the peer device generates a new control plane message including (1) a network address of the peer device as a next hop value, (2) the prefix value from the control plane message, and (3) a label stack including (i) the at least one label from the control plane message, and (ii) a local label associated with the peer device.