Abstract: A node is configured to operate in a Segment Routing (SR) over Internet Protocol version 6 (SRv6) network, and the node includes circuitry configured to determine a Segment Identifier (SID) list for a forward path in the SRv6 network and SID list for a reverse path in the SRv6 network; and transmit a monitoring packet on the forward path including a Segment Routing Header (SRH) with the SID list for the forward path, and further including the SID list for the reverse path in the monitoring packet, for a SRH of a reply to the monitoring packet. The circuitry can be further configured to receive the reply to the monitoring packet, with the reply having been on a same or different tunnel as the monitoring packet, for monitoring liveliness thereof.

Abstract: Systems and methods at a reflector node include steps of receiving a request from an initiator node in the network, the request having been sent in a forward direction from the initiator node to the reflector node to discover a reverse path in a reverse direction from the reflector node to the initiator node, and transmitting a reply to the initiator node with one or more reverse Segment Routing (SR) policies that meet one or more path constraint parameters in the request. The reply can include associated Segment Identifiers (SIDs) for the one or more reverse SR policies. The steps can further include implementing one of Bidirectional Forwarding Detection (BFD) or a Multi-Protocol Label Switching (MPLS) Ping procedure with the initiator node, sent over one of the one or more reverse SR policies.

Abstract: Systems and methods for performing connectivity checks, such as Seamless Bidirectional Forwarding Detection (S-BFD), are provided. A node is configured to operate in a network, the node is a Seamless Bidirectional Forwarding Detection (S-BFD) reflector node configured to operate an S-BFD session with an S-BFD initiator node. The node includes circuitry configured to, responsive to an S-BFD discriminator change in the S-BFD session to a new discriminator for the S-BFD session, cache an old discriminator for the S-BFD session, and receive, process, and respond to a S-BFD request from the S-BFD initiator node with an S-BFD response including one of the new discriminator or the old discriminator.

Abstract: A node is configured to operate in a Segment Routing (SR) over Internet Protocol version 6 (SRv6) network, and the node includes circuitry configured to determine a Segment Identifier (SID) list for a forward path in the SRv6 network and SID list for a reverse path in the SRv6 network; and transmit a monitoring packet on the forward path including a Segment Routing Header (SRH) with the SID list for the forward path, and further including the SID list for the reverse path in the monitoring packet, for a SRH of a reply to the monitoring packet. The circuitry can be further configured to receive the reply to the monitoring packet, with the reply having been on a same or different tunnel as the monitoring packet, for monitoring liveliness thereof.

Abstract: Systems and methods for performing connectivity checks, such as Seamless Bidirectional Forwarding Detection (S-BFD), are provided. A method, according to one implementation, includes receiving, at a responding node, an entry configured to call for a modification of an identification element (from an old identifier value to a new identifier value) used for identifying the responding node with respect to other nodes of a network. The old and new identifier values are cached in a memory device. Also, the method includes providing a reply packet back to an initiating node in response to receipt of a request packet from the initiating node. The request packet is related to a connectivity check for testing the connectivity between the initiating node and the responding node. In addition, the request packet is able to identify the responding node by either the old identifier value or the new identifier value.

Abstract: Systems and methods at a reflector node include steps of receiving a request from an initiator node in the network, the request having been sent in a forward direction from the initiator node to the reflector node to discover a reverse path in a reverse direction from the reflector node to the initiator node, and transmitting a reply to the initiator node with one or more reverse Segment Routing (SR) policies that meet one or more path constraint parameters in the request. The reply can include associated Segment Identifiers (SIDs) for the one or more reverse SR policies. The steps can further include implementing one of Bidirectional Forwarding Detection (BFD) or a Multi-Protocol Label Switching (MPLS) Ping procedure with the initiator node, sent over one of the one or more reverse SR policies.

Abstract: Systems and methods for enabling Bidirectional Forwarding Detection (BFD) over a selected reverse path are provided. A process, according to one implementation, include sending an echo request in a forward direction from an initiator node to a reflector node. For example, the initiator node and reflector node may be configured to operate in a network having no or different centralized controller that manages both the initiator node and reflector node. The echo request may be sent to the reflector node to discover a reverse path in a reverse direction from the reflector node to the initiator node. Also, the reverse path is discovered for the purpose of initiating a Bidirectional Forwarding Detection (BFD) or Multi-Protocol Label Switching (MPLS) Ping procedure.

Abstract: Systems and methods for monitoring the continuity between endpoints in a network are provided. A process, according to one implementation, includes entering a first list of one or more Segment Identifiers (SIDs) into a Bidirectional Forwarding Detection (BFD) request packet, the first list of one or more SIDs defining a Segment-Routing Traffic-Engineering (SR-TE) forward path from a source node to a destination node. The process also includes entering a second list of one or more SIDs into the BFD request packet, the second list of one or more SIDs defining an SR-TE reverse path back from the destination node that eliminates involvement of a BFD reflector of the destination node. Also, the process includes entering a revised-BFD request into the BFD request packet, the revised-BFD request having a Your Discriminator field set to a discriminator value associated with the source node.

Abstract: Systems, methods, and computer-readable media are provided for re-establishing a Bidirectional Forwarding Detection (BFD) session. A method, according to one implementation, include a step of receiving, at a local end device, a first BFD control packet from a remote end device when a BFD session between the local end device and remote end device is down. For example, the first BFD control packet may include a remote discriminator number associated with the remote end device and a local discriminator number presumed to be associated with the local end device. The method further includes a step of replying to the remote end device with a second BFD control packet including an actual discriminator number of the local end device in response to determining that the local discriminator number included in the first BFD control packet is non-zero and differs from the actual discriminator number of the local end device.

Abstract: Systems and methods for performing connectivity checks, such as Seamless Bidirectional Forwarding Detection (S-BFD), are provided. A method, according to one implementation, includes receiving, at a responding node, an entry configured to call for a modification of an identification element (from an old identifier value to a new identifier value) used for identifying the responding node with respect to other nodes of a network. The old and new identifier values are cached in a memory device. Also, the method includes providing a reply packet back to an initiating node in response to receipt of a request packet from the initiating node. The request packet is related to a connectivity check for testing the connectivity between the initiating node and the responding node. In addition, the request packet is able to identify the responding node by either the old identifier value or the new identifier value.

Abstract: Systems and methods for enabling Bidirectional Forwarding Detection (BFD) over a selected reverse path are provided. A process, according to one implementation, include sending an echo request in a forward direction from an initiator node to a reflector node. For example, the initiator node and reflector node may be configured to operate in a network having no or different centralized controller that manages both the initiator node and reflector node. The echo request may be sent to the reflector node to discover a reverse path in a reverse direction from the reflector node to the initiator node. Also, the reverse path is discovered for the purpose of initiating a Bidirectional Forwarding Detection (BFD) or Multi-Protocol Label Switching (MPLS) Ping procedure.

Abstract: Systems, methods, and computer-readable media are provided for re-establishing a Bidirectional Forwarding Detection (BFD) session. A method, according to one implementation, include a step of receiving, at a local end device, a first BFD control packet from a remote end device when a BFD session between the local end device and remote end device is down. For example, the first BFD control packet may include a remote discriminator number associated with the remote end device and a local discriminator number presumed to be associated with the local end device. The method further includes a step of replying to the remote end device with a second BFD control packet including an actual discriminator number of the local end device in response to determining that the local discriminator number included in the first BFD control packet is non-zero and differs from the actual discriminator number of the local end device.

Abstract: Systems and methods for incorporating a new channel-type value in the header of a Generic Associated Channel (G-ACh) for Connectivity Fault Management (CFM) Layer-2 packets over Multi-Protocol Label Switching (MPLS) networks are provided. The channel-type value of the G-ACh header may be used for identification of the network-generated CFM Layer-2 packets. In one implementation, a system may include a processing device and a memory device, where the memory device may be configured to store instructions that, when executed, cause the processing device to obtain a Connectivity Fault Management (CFM) packet, encapsulate the CFM packet with Pseudo-Wire (PW) and Label-Switched Path (LSP) labels to create an expanded packet, and incorporate a specific channel-type value in a G-ACh header of the expanded packet to uniquely identify the CFM packet.

Abstract: Systems and methods for incorporating a new channel-type value in the header of a Generic Associated Channel (G-ACh) for Connectivity Fault Management (CFM) Layer-2 packets over Multi-Protocol Label Switching (MPLS) networks are provided. The channel-type value of the G-ACh header may be used for identification of the network-generated CFM Layer-2 packets. In one implementation, a system may include a processing device and a memory device, where the memory device may be configured to store instructions that, when executed, cause the processing device to obtain a Connectivity Fault Management (CFM) packet, encapsulate the CFM packet with Pseudo-Wire (PW) and Label-Switched Path (LSP) labels to create an expanded packet, and incorporate a specific channel-type value in a G-ACh header of the expanded packet to uniquely identify the CFM packet.

Abstract: Methods, systems, and computer readable media for sustaining active control over concurrent session connections are disclosed. According to one example, the disclosed subject matter describes herein a method that includes opening a plurality of session connections to a device under test (DUT), wherein each of the opened session connections is associated with an initial window size value and receiving data from the DUT via one or more of the opened session connections. The method further includes communicating a packet instructing the DUT to cease sending the data via the one or more of the opened session connections in the event the data received from the DUT equals the initial session window size value and utilizing at least one of the opened session connections not being used to receive the data from the DUT in order to resume active communication of the data with the DUT.

Abstract: Methods, systems, and computer readable media for sustaining active control over concurrent session connections are disclosed. According to one example, the disclosed subject matter describes herein a method that includes opening a plurality of session connections to a device under test (DUT), wherein each of the opened session connections is associated with an initial window size value and receiving data from the DUT via one or more of the opened session connections. The method further includes communicating a packet instructing the DUT to cease sending the data via the one or more of the opened session connections in the event the data received from the DUT equals the initial session window size value and utilizing at least one of the opened session connections not being used to receive the data from the DUT in order to resume active communication of the data with the DUT.