Abstract: An apparatus and method is disclosed for segment routing (SR). In one embodiment, the method includes a node creating a segment stack that identifies one segment calculated using a first algorithm and a second segment calculated using a second, different algorithm. The node then attaches this header to a packet and sends it to another node.

Abstract: A method, communications processing device, and computer readable medium for MPLS segment routing are disclosed. One embodiment of the method comprises generating a first link-state packet comprising a first data structure. The first data structure maps a first portcode to a link connecting the first router within the network or to an additional router reachable from the first router. The method embodiment further includes receiving an incoming data packet encapsulated with a header comprising an incoming portcode stack having the first portcode as its uppermost portcode. The method embodiment further includes removing the first portcode from the incoming portcode stack to create an outgoing portcode stack for an outgoing data packet, and forwarding the outgoing data packet via a port, of the first router, identified by the first portcode.

Abstract: A method, network device, and computer readable medium are disclosed. In one embodiment of the method, a data packet is received at a node within a first segment routing enabled access network. The first access network is connected, via a first area edge node, to a first area of a subdivided segment routing enabled network, and a specified destination for the data packet is reachable via a second segment routing enabled access network connected to the subdivided network. The method embodiment further includes receiving from a centralized controller a remote segment identifier stack, where the remote segment identifier stack encodes a path extending from the first area edge node to the second access network. The embodiment of the method continues with encapsulating the data packet with a full segment identifier stack comprising the remote segment identifier stack, and forwarding the encapsulated data packet toward the first area edge node.

Abstract: A system and method are disclosed for generating segment routing (SR) segment lists. In one embodiment, a node receives information that identifies a path from a first node to a second node. Based on the received path, a set of segment identifiers that encodes the path is generated. A packet that is forwarded along the set of segment identifiers travels the received path.

Abstract: An apparatus and method is disclosed for segment routing (SR). In one embodiment, the method includes a node creating a segment stack that identifies one segment calculated using a first algorithm and a second segment calculated using a second, different algorithm. The node then attaches this header to a packet and sends it to another node.

Abstract: An apparatus and method is disclosed for segment routing (SR). In one embodiment, the method includes a node creating a segment stack that identifies one segment calculated using a first algorithm and a second segment calculated using a second, different algorithm. The node then attaches this header to a packet and sends it to another node.

Abstract: A method, network device, and computer readable medium are disclosed. In one embodiment of the method, a data packet is received at a node within a first segment routing enabled access network. The first access network is connected, via a first area edge node, to a first area of a subdivided segment routing enabled network, and a specified destination for the data packet is reachable via a second segment routing enabled access network connected to the subdivided network. The method embodiment further includes receiving from a centralized controller a remote segment identifier stack, where the remote segment identifier stack encodes a path extending from the first area edge node to the second access network. The embodiment of the method continues with encapsulating the data packet with a full segment identifier stack comprising the remote segment identifier stack, and forwarding the encapsulated data packet toward the first area edge node.

Abstract: A method, communications processing device, and computer readable medium for MPLS segment routing are disclosed. One embodiment of the method comprises generating a first link-state packet comprising a first data structure. The first data structure maps a first portcode to a link connecting the first router within the network or to an additional router reachable from the first router. The method embodiment further includes receiving an incoming data packet encapsulated with a header comprising an incoming portcode stack having the first portcode as its uppermost portcode. The method embodiment further includes removing the first portcode from the incoming portcode stack to create an outgoing portcode stack for an outgoing data packet, and forwarding the outgoing data packet via a port, of the first router, identified by the first portcode.

Abstract: MPLS segment routing is disclosed. In one embodiment, a first core router generates a first data structure that maps first portcodes to respective identities of first neighbor routers or respective first links, wherein the first portcodes identify respective first ports of the first core router, and wherein the first ports are coupled to the first neighbor routers, respectively, via the first links, respectively. The first core router generates and transmits a first link-state packet, wherein the first link-state packet comprises an identity of the first core router and the first data structure.

Abstract: A method, apparatus, and computer readable medium are disclosed. In one embodiment of the method, a packet and a segment ID stack is received at a first segment routing enabled node. The segment ID stack includes a plurality of segment IDs, one or which is a first area-segment ID that identifies a first area of a subdivided segment routing network. An egress interface of the first segment routing enabled node is selected based on the first area-segment ID. Thereafter, the packet is forwarded via the selected egress interface.

Abstract: A method and device are disclosed for opportunistic compression of routing segment identifiers. In one embodiment, the method includes participating in routing of a first data packet through a first node in a network, and subsequently entering into an arrangement with an adjacent node in the network. The first data packet includes a first plurality of routing segment identifiers, and additional data packets to be routed through the first node also include the first plurality of routing segment identifiers. The arrangement entered into includes representation of the first plurality of routing segment identifiers by a single compression identifier. The method further includes participating in routing of at least one of the additional data packets using the compression identifier instead of the first plurality of routing segment identifiers. In an embodiment, the device includes one or more network interfaces and a processor configured to perform the steps of the method.

Abstract: A method, apparatus, and computer readable medium are disclosed. In one embodiment of the method, a packet and a segment ID stack is received at a first segment routing enabled node. The segment ID stack includes a plurality of segment IDs, one or which is a first area-segment ID that identifies a first area of a subdivided segment routing network. An egress interface of the first segment routing enabled node is selected based on the first area-segment ID. Thereafter, the packet is forwarded via the selected egress interface.

Abstract: One or more functions to be performed on a packet at one or more network nodes along a network path are determined at a network device. A packet is generated which includes a packet header. Included in the packet header are an instruction pointer and an instruction portion. A first instruction for the one or more functions to be performed at the one or more network nodes is written to the instruction portion. Additionally, a value pointing to the first instruction is written to the instruction pointer. The packet is transmitted along the network path from the network device.

Abstract: In one embodiment, a packet and a segment ID stack is received at a node. The segment ID stack includes a plurality of segment IDs, one or which is a first area-segment ID that identifies a first area of a subdivided network. One of a plurality of forwarding tables at the node is selected based on the first area-segment ID. Thereafter, the packet is forwarded based on information contained in the selected forwarding table.

Abstract: Various techniques can be used to avoid loops during network convergence after a topology change such as a failure. For example, a method can involve detecting a failure that disrupts an existing forwarding path between a node and a destination node; calculating at least one updated forwarding path from the node to the destination node; identifying a maximum time for at least a portion of the network to reach a post-convergence state with respect to the failure; until the maximum time has elapsed at the node, explicitly specifying at least a portion of the updated forwarding path in packet headers of any packets being sent from the node to the destination node; and after the maximum time has elapsed at the node, non-explicitly specifying the portion of the updated forwarding path in packet headers of any additional packets being sent from the node to the destination node.

Abstract: A method and system are disclosed for use of segment routing in monitoring of a network path. In one embodiment, the method includes selecting a plurality of segment identifiers and assembling the segment identifiers into a segment identifier stack, where the segment identifier stack encodes a test path within the network for attempted routing of a test message. The method may further include inserting the segment identifier stack into a header associated with the test message, and forwarding the test message according to an entry in a forwarding table corresponding to the segment identifier at the top of the segment identifier stack. Interior gateway protocol advertisements may be used to communicate segment identifiers for creating or updating of the data structure or the forwarding table. In an embodiment, the system includes one or more network interfaces and a processor configured to perform the steps of the method.

Abstract: Various techniques can be used to avoid loops during network convergence after a topology change such as a failure. For example, a method can involve detecting a failure that disrupts an existing forwarding path between a node and a destination node; calculating at least one updated forwarding path from the node to the destination node; identifying a maximum time for at least a portion of the network to reach a post-convergence state with respect to the failure; until the maximum time has elapsed at the node, explicitly specifying at least a portion of the updated forwarding path in packet headers of any packets being sent from the node to the destination node; and after the maximum time has elapsed at the node, non-explicitly specifying the portion of the updated forwarding path in packet headers of any additional packets being sent from the node to the destination node.

Abstract: MPLS segment routing is disclosed. In one embodiment, a first core router generates a first data structure that maps first portcodes to respective identities of first neighbor routers or respective first links, wherein the first portcodes identify respective first ports of the first core router, and wherein the first ports are coupled to the first neighbor routers, respectively, via the first links, respectively. The first core router generates and transmits a first link-state packet, wherein the first link-state packet comprises an identity of the first core router and the first data structure.

Abstract: MPLS segment routing is disclosed. In one embodiment, a first core router generates a first data structure that maps first portcodes to respective identities of first neighbor routers or respective first links, wherein the first portcodes identify respective first ports of the first core router, and wherein the first ports are coupled to the first neighbor routers, respectively, via the first links, respectively. The first core router generates and transmits a first link-state packet, wherein the first link-state packet comprises an identity of the first core router and the first data structure.

Abstract: A method and device are disclosed for opportunistic compression of routing segment identifiers. In one embodiment, the method includes participating in routing of a first data packet through a first node in a network, and subsequently entering into an arrangement with an adjacent node in the network. The first data packet includes a first plurality of routing segment identifiers, and additional data packets to be routed through the first node also include the first plurality of routing segment identifiers. The arrangement entered into includes representation of the first plurality of routing segment identifiers by a single compression identifier. The method further includes participating in routing of at least one of the additional data packets using the compression identifier instead of the first plurality of routing segment identifiers. In an embodiment, the device includes one or more network interfaces and a processor configured to perform the steps of the method.