Abstract: In one embodiment, a method comprises detecting, by a provider edge router configured for providing reachability for core network traffic to a prescribed destination address prefix, a backup provider edge router relative to the prescribed destination address prefix; allocating, by the provider edge router, a distinct protected next-hop address for reachability to at least the destination address prefix via the provider edge router; and sending via a core network, by the provider edge router, repair information for the prescribed destination address prefix to ingress provider edge routers and a BGP-free core network router in the core network, the repair information enabling the ingress provider edge routers to insert primary and backup switching labels into each data packet of the core network traffic enabling the BGP-free core network router to reroute the received packet to the backup provider edge router if the provider edge router is unavailable.

Abstract: In one embodiment, a method comprises generating, by a first provider edge router associated with a first segment identifier, a primary label for reaching a destination, and repair information for reaching the destination if a second provider edge router is unavailable to reach the destination; allocating, by the first provider edge router, a first protected next-hop address associated with the first segment identifier for protected reachability to at least the destination; and sending via a core network, by the first provider edge router, an advertisement specifying the label and the repair information, enabling an ingress provider edge router to insert, into a data packet destined for the destination, the labels from the first provider edge router and the second provider edge router based on the repair information, for fast rerouting to the destination via one of the first or second provider edge router if the other is unavailable.

Abstract: In one embodiment, a method comprises detecting, by a provider edge router configured for providing reachability for core network traffic to a prescribed destination address prefix, a backup provider edge router relative to the prescribed destination address prefix; allocating, by the provider edge router, a distinct protected next-hop address for reachability to at least the destination address prefix via the provider edge router; and sending via a core network, by the provider edge router, repair information for the prescribed destination address prefix to ingress provider edge routers and a BGP-free core network router in the core network, the repair information enabling the ingress provider edge routers to insert primary and backup switching labels into each data packet of the core network traffic enabling the BGP-free core network router to reroute the received packet to the backup provider edge router if the provider edge router is unavailable.

Abstract: In one embodiment, a method comprises detecting, by a first provider edge router, a second provider edge router providing reachability to a prescribed destination address prefix via a protected next hop address; allocating, by the first provider edge router, a minor forwarding table associated with the second provider edge router and identifying a destination used by the second provider edge router for reaching the prescribed destination address prefix; and the first provider edge router sending repair information to a Border Gateway Protocol (BGP)-free core network router in the core network, the repair information enabling the BGP-free core network router to add a context label and reroute a received data packet to the first provider edge router if the second provider edge router is unavailable, the context label enabling the first provider edge router to identify the destination in the rerouted data packet for delivery to the destination address prefix.

Abstract: An apparatus and method for enabling interoperability of segment routing (SR) enabled nodes and LDP enabled nodes in a network domain. In one embodiment, the method may include mapping a first node identifier (ID) to a first segment ID in memory, wherein the first node ID uniquely identifies a first node within a network domain, and wherein the first node is not SR enabled. A message is generated and subsequently transmitted directly or indirectly to another node within the network domain, wherein the message comprises the first node ID mapped to the first segment ID, and wherein the other node is SR enabled.

Abstract: Various techniques can be used to advertise adjacency segment identifiers (IDs) within a segment routing (SR) network. For example, a method, performed by a first node, can involve identifying an adjacency segment between a first node and a second node; assigning an identifier to the adjacency segment; and sending an Intermediate-System-to-Intermediate-System (IS-IS) hello (IIH) message to another node. The adjacency advertisement includes the identifier. If the adjacency segment is part of a LAN, the IIH message can be sent to a designated node that aggregates adjacency segment ID advertisements for the other nodes on the LAN.

Abstract: In one embodiment, a method includes determining, by an edge router, a plurality of prefixes reachable by the edge router, each prefix indicating a range of Internet Protocol (IP) addresses. The method further includes grouping, by the edge router, the plurality of prefixes into one or more groups, wherein each group is associated with a particular repair edge router and the prefixes in each particular group are reachable by both the edge router and the particular repair edge router associated with the particular group. The method further includes communicating instructions, from the edge router to a core router, to send data packets associated with the prefixes in each particular group to the particular edge router associated with the particular group if the edge router becomes unreachable.

Abstract: An apparatus and method is disclosed for segment routing (SR) over label distribution protocol (LDP). In one embodiment, the method includes a node receiving a packet with an attached segment ID. In response, the node may attach a label to the packet. Thereafter, the node may forward the packet with the attached label and segment ID to another node via a label switched path (LSP).

Abstract: A method and apparatus for forwarding packets through a network domain that contains nodes that are label distribution protocol (LDP) enabled and nodes that are segment routing (SR) enabled. In one embodiment, the method may include a network node receiving a packet with a label attached thereto. The node swaps the label with a segment identifier (ID). The node then forwards the packet to an SR node. In another embodiment, the method may include a network node receiving a packet with a segment ID attached thereto. The node swaps the segment ID with a label. The node then forwards the packet to an LDP enabled node.

Abstract: An apparatus and method for using indexed segment identifiers in segment routing. An example method involves receiving a globally unique index value at a node. The method also involves receiving a base value at the node, where the base value comprises a segment routing value configured to identify a nodal segment. The method then involves calculating a segment identifier based on the index value and the base value.

Abstract: In one embodiment, a method includes determining, by an edge router, a plurality of prefixes reachable by the edge router, each prefix indicating a range of Internet Protocol (IP) addresses. The method further includes grouping, by the edge router, the plurality of prefixes into one or more groups, wherein each group is associated with a particular repair edge router and the prefixes in each particular group are reachable by both the edge router and the particular repair edge router associated with the particular group. The method further includes communicating instructions, from the edge router to a core router, to send data packets associated with the prefixes in each particular group to the particular edge router associated with the particular group if the edge router becomes unreachable.

Abstract: In one embodiment, a method includes determining, by an edge router, a plurality of prefixes reachable by the edge router, each prefix indicating a range of Internet Protocol (IP) addresses. The method further includes grouping, by the edge router, the plurality of prefixes into one or more groups, wherein each group is associated with a particular repair edge router and the prefixes in each particular group are reachable by both the edge router and the particular repair edge router associated with the particular group. The method further includes communicating instructions, from the edge router to a core router, to send data packets associated with the prefixes in each particular group to the particular edge router associated with the particular group if the edge router becomes unreachable.

Abstract: Methods and apparatus are disclosed for a token bucket metering or policing system with a delayed filing scheme which may be used, inter alia, in a computer or communications system, such as a packet switching system, router, or other device. The token bucket scheme updates the number of tokens in a particular bucket in response to an expiration of a timer or a receipt of a packet corresponding to a packet stream being metered or policed based on the particular bucket. One implementation determines whether a difference between a current time value with a last bucket update time value equals or exceeds a predetermined time interval. If the difference between the current time value with the last bucket update time value equals or exceeds the predetermined time interval, then a predetermined number of tokens is added to a bucket, and the last bucket update time value is incremented by approximately the predetermined time interval.