Abstract: A method of exposing a maximum segment identifier depth (MSD) value of the network device is described. The method comprises transmitting to a centralized controller an attribute Type Length Value (TLV). A type of the attribute TLV includes a type of a maximum segment identifier depth (MSD) indicating that the MSD is a link MSD, a length of the attribute TLV includes a length of the MSD, and a value of the attribute TLV includes the MSD, which is a maximum number of segment routing (SR) labels supported at a link of the network node. The centralized controller is to use the attribute TLV to compute an SR tunnel with one or more SR labels, a label stack depth of the SR tunnel does not exceed the MSD, and the SR labels are used for steering a packet through an SR network.

Abstract: Techniques for exposing maximum node and/or link segment identifier depth using OSPF are described. A network element in a Segment Routing (SR) network transmits a Type Length Value (TLV) element including a Maximum Segment Identifier Depth (MSD) value utilizing OSPF. The MSD value identifies a maximum number of segment identifier (SID) labels that the network element is able to push into packet headers of received packets to enable forwarding of the received packets through the SR network. The network element receives, from a controller, data for a path to be utilized by the network element for forwarding the received packets through the SR network. The data includes one or more SID labels to be pushed into the received packets, and the SID labels have fewer than or equal to the MSD value. The controller and the network element do not utilize Path Computation Element Protocol (PCEP) over a southbound interface.

Abstract: A method is implemented by a network device to establish a bidirectional forwarding detection (BFD) session with a defined return path to enable detection of data plane failures between an active node and a passive node in a network where a forward path and a reverse path between the active node and the passive node are not co-routed. The method includes receiving a label switched path (LSP) ping including a BFD discriminator type length value (TLV) of the active node and a return path TLV describing a return path to the active node. The BFD discriminator of the active node and a BFD discriminator of the passive node are associated with the BFD session. The return path is associated with the BFD session between the active node and the passive node, and BFD control packets are sent to the active node using the return path to detect a failure on the return path.

Abstract: Techniques for exposing maximum node and/or link segment identifier depth using IS-IS are described. A network element in a Segment Routing (SR) network transmits a Type Length Value (TLV) element including a Maximum Segment Identifier Depth (MSD) value. The MSD value identifies a maximum number of segment identifier (SID) labels that the network element is able to push into packet headers of received packets to enable forwarding of the received packets through the SR network. The network element receives, from a controller, data for a path to be utilized by the network element for forwarding the received packets through the SR network. The data includes one or more SID labels to be pushed into the received packets, and the SID labels include fewer than or equal to the MSD value. The controller and the network element do not utilize the Path Computation Element Protocol (PCEP) over a southbound interface.

Abstract: Techniques for exposing maximum node and/or link segment identifier depth using OSPF are described. A network element in a Segment Routing (SR) network transmits a Type Length Value (TLV) element including a Maximum Segment Identifier Depth (MSD) value utilizing OSPF. The MSD value identifies a maximum number of segment identifier (SID) labels that the network element is able to push into packet headers of received packets to enable forwarding of the received packets through the SR network. The network element receives, from a controller, data for a path to be utilized by the network element for forwarding the received packets through the SR network. The data includes one or more SID labels to be pushed into the received packets, and the SID labels have fewer than or equal to the MSD value. The controller and the network element do not utilize Path Computation Element Protocol (PCEP) over a southbound interface.

Abstract: Techniques for exposing maximum node and/or link segment identifier depth using IS-IS are described. A network element in a Segment Routing (SR) network transmits a Type Length Value (TLV) element including a Maximum Segment Identifier Depth (MSD) value. The MSD value identifies a maximum number of segment identifier (SID) labels that the network element is able to push into packet headers of received packets to enable forwarding of the received packets through the SR network. The network element receives, from a controller, data for a path to be utilized by the network element for forwarding the received packets through the SR network. The data includes one or more SID labels to be pushed into the received packets, and the SID labels include fewer than or equal to the MSD value. The controller and the network element do not utilize the Path Computation Element Protocol (PCEP) over a southbound interface.

Abstract: Methods and apparatuses for enabling sub-seconds link failure detection in a multi-chassis link aggregation group (MC-LAG) system are described. A first network device of a packet network transmits an IP packet over a first link that is part of the MC-LAG, where the MC-LAG couples the first network device with a second network device and a third network device and the second and third network devices are part of an Inter-Chassis Redundancy (ICR) system. The IP packet includes a payload including a Bidirectional Forwarding Detection (BFD) control packet, where the destination address of the IP packet is one of a multicast IP address and a broadcast IP address.

Abstract: A router operates in both a Segment Routing (SR) network portion and a Multiprotocol Label Switching (MPLS) network portion of a network that utilizes Open Shortest Path First (OSPF). The router receives an OSPF advertisement message originated by a mapping server that includes a sub-Type-length-value (sub-TLV) element that identifies a preferred type of path across the MPLS network portion for an identifiable set of traffic that is to be received by the router from the SR network portion. The router identifies, based at least in part upon the sub-TLV element, one path of a plurality of available paths across the MPLS network portion for the identifiable set of traffic, and configures its forwarding plane to utilize the identified one path accordingly for the identifiable set of traffic. The OSPF advertisement message can be an OSPF LSA, and can carry an Extended Prefix Range TLV including the sub-TLV element.

Abstract: A method of exposing a maximum segment identifier depth (MSD) value of the network device is described. The method comprises transmitting to a centralized controller an attribute Type Length Value (TLV). A type of the attribute TLV includes a type of a maximum segment identifier depth (MSD) indicating that the MSD is a link MSD, a length of the attribute TLV includes a length of the MSD, and a value of the attribute TLV includes the MSD, which is a maximum number of segment routing (SR) labels supported at a link of the network node. The centralized controller is to use the attribute TLV to compute an SR tunnel with one or more SR labels, a label stack depth of the SR tunnel does not exceed the MSD, and the SR labels are used for steering a packet through an SR network.

Abstract: A method implemented by a network device acting as a border gateway protocol (BGP) speaker, of exposing a maximum segment identifier depth (MSD) value of the network device is described. The method comprises encoding the MSD value into a BGP Link State (BGP-LS) extension message. The BGP-LS extension message includes a type, a length and a MSD value. The type indicates the type of the MSD value, the length indicates the length of the MSD value and the MSD value indicates a lowest MSD value supported by the network device for enabling segment routing. The method continues with transmitting the BGP-LS extension message including the type, the length, and the MSD value to a network controller, where the network controller is to use the MSD value to compute a segment routing path including the network device.

Abstract: A router operates in both a Segment Routing (SR) network portion and a Multiprotocol Label Switching (MPLS) network portion of a network that utilizes Intermediate System to Intermediate System (IS-IS). The router receives an IS-IS advertisement message originated by a mapping server that includes a sub-Type-length-value (sub-TLV) element that identifies a preferred type of path across the MPLS network portion for an identifiable set of traffic to be received by the router from the SR network portion. The router identifies, based at least in part upon the sub-TLV element, one path of a plurality of available paths across the MPLS network portion for the identifiable set of traffic, and configures its forwarding plane to utilize the identified one path for the identifiable set of traffic. The IS-IS advertisement message can be an IS-IS TLV such as a SID/Label Binding TLV 149 or Multi-topology SID/Label Binding TLV 150.

Abstract: Methods and apparatuses for enabling sub-seconds link failure detection in a multi-chassis link aggregation group (MC-LAG) system are described. A first network device of a packet network transmits a Multiprotocol Label Switching (MPLS) encapsulated packet over a first link that is part of the MC-LAG, where the MC-LAG couples the first network device with a second network device and a third network device and the second and third network devices are part of an inter-chassis redundancy (ICR) system. The MPLS encapsulated packet includes a generic associated channel header (ACH) and a payload, and where the payload includes a bidirectional forwarding detection (BFD) control packet.

Abstract: A method is implemented by a first Provider Edge (PE) network device in a network to configure a pseudo-wire (PW) between the first PE network device and a second PE network device in the network using Intermediate System to Intermediate System (IS-IS). The method includes receiving a first LSP update flooded in the network by the second PE network device via IS-IS, where the first LSP update advertises the PW. The method further includes configuring a local forwarding information base with a local PW label associated with the PW such that the first PE network device forwards traffic encapsulated with the local PW label to an Attachment Circuit associated with the PW and flooding a second LSP update in the network via IS-IS that includes an indication that the first PE network device is ready to receive traffic from the second PE network device over the PW.

Abstract: Exemplary methods include a first network device participating in an election process to determine a designated bit forwarding router (D-BFR). The methods include in response to determining the first network device is elected to be the D-BFR, performing D-BFR operations comprising assigning one or more bitmask positions (BMPs) to one or more bit forwarding egress routers (BFERs) and advertising the assigned one or more BMPs. The method may further include one or more of determining an elected bitmask (BM) length based on maximum local BM lengths advertised by other BFRs and determining an elected tree type based on supported tree types advertised by other BFRs.

Abstract: Servicing a pseudowire communication across multiple Administrative Systems (AS) by components of packet data networks. A first Provider Edge (PE) router of a first AS receives a first Interior Gateway Protocol (IGP) message from a source PE router of the first AS that includes pseudowire data. The first PE router creates a first Border Gateway Protocol Link State (BGP-LS) message that includes the pseudowire data and transmits the first BGP-LS message to a second PE router of a second AS and intended for a destination PE router of the second AS. The first PE router then receives a second BGP-LS message from the second PE router that includes modified pseudowire data. The first PE router creates a second IGP message that includes the modified pseudowire data and transmits the second IGP message to the source PE router.

Abstract: A method is implemented by a first Provider Edge (PE) network device in a network to configure a pseudo-wire (PW) between the first PE network device and a second PE network device in the network using an Interior Gateway Protocol (IGP). The method includes receiving a first advertisement message flooded in the network by the second PE network device via the IGP, where the first advertisement message advertises the PW. The method further includes configuring a local forwarding information base with a local PW label associated with the PW such that the first PE network device forwards traffic encapsulated with the local PW label to an Attachment Circuit associated with the PW and flooding a second advertisement message in the network via the IGP that includes an indication that the first PE network device is ready to receive traffic from the second PE network device over the PW.

Abstract: A method is implemented by a node of a network domain having a plurality of nodes, where the node functions as an ingress node of the network domain for a data flow. The method enables data flow analysis across the network domain. The method includes receiving a data packet belonging to a data flow at an ingress node of the network domain, determining whether the data packet is to be marked for the data flow analysis, determining whether an egress node of the network domain for the data flow supports data packet marking, marking the data packet with a marking label indicating to supporting nodes in the network domain that the data packet is to be processed for data flow analysis, and forwarding the data packet toward the egress node of the network domain.

Abstract: A provider edge (PE) router and methods for establishing a pseudowire using open shortest path first (OSPF) link state advertisement (LSA) messages. The pseudowire links the PE router with a remote PE router through a packet switched network (PSN), and emulates other communications protocols to provide customer edge (CE) equipment connected to the PE routers the appearance of a dedicated private circuit.

Abstract: Servicing a pseudowire communication across multiple Administrative Systems (AS) by components of packet data networks. A first Provider Edge (PE) router of a first AS receives a first Interior Gateway Protocol (IGP) message from a source PE router of the first AS that includes pseudowire data. The first PE router creates a first Border Gateway Protocol Link State (BGP-LS) message that includes the pseudowire data and transmits the first BGP-LS message to a second PE router of a second AS and intended for a destination PE router of the second AS. The first PE router then receives a second BGP-LS message from the second PE router that includes modified pseudowire data. The first PE router creates a second IGP message that includes the modified pseudowire data and transmits the second IGP message to the source PE router.

Abstract: A method is implemented by a first Provider Edge (PE) network device in a network to configure a pseudo-wire (PW) between the first PE network device and a second PE network device in the network using an Interior Gateway Protocol (IGP). The method includes receiving a first advertisement message flooded in the network by the second PE network device via the IGP, where the first advertisement messge advertises the PW. The method further includes configuring a local forwarding information base with a local PW label associated with the PW such that the first PE network device forwards traffic encapsulated with the local PW label to an Attachment Circuit associated with the PW and flooding a second advertisement message in the network via the IGP that includes an indication that the first PE network device is ready to receive traffic from the second PE network device over the PW.