Abstract: The disclosed techniques can collect and transport telemetry information on-path when a packet of a service flow traverses a communication network. The collected telemetry information can be analyzed to identify potential issues experienced by a user of a service and simplify the association of data with the service. Thus, apparatuses, methods, computer readable media, and systems are disclosed for an on-path collection and transportation of telemetry information in a communication network.

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 of operation of a Multiprotocol Label Switching network involves, in an active node of the network, receiving a first data packet from a source node and forwarding the first data packet to a destination node. At the same time, the active node measures a residence time of the first data packet in the active node. The active node then sends a further data packet containing residence time information.

Abstract: This disclosure addresses improving the reliability of network connections between nodes, detection of failures of network connections, and the reduction of control packets exchanged between nodes. A second node may stop sending control packets to a first node causing a reduction in network throughput and increased network capacity. The network connection from the first node to the second may be of a first type and the connection from the second node to the first node may be of a second type. When a failure of the connection of the first type occurs, communication of the failure may be sent in a flag from the second node to the first node using the second type. A response to the flag received at the first node may be sent to the second node. The response may be sent using the second type of network connection because the first type failed.

Abstract: This disclosure addresses improving the reliability of network connections between nodes, detection of failures of network connections, and the reduction of control packets exchanged between nodes. A second node may stop sending control packets to a first node causing a reduction in network throughput and increased network capacity. The network connection from the first node to the second may be of a first type and the connection from the second node to the first node may be of a second type. When a failure of the connection of the first type occurs, communication of the failure may be sent in a flag from the second node to the first node using the second type. A response to the flag received at the first node may be sent to the second node. The response may be sent using the second type of network connection because the first type failed.

Abstract: A packet communication method that generates a header that includes information to route a packet through a ring communication network is described. The header can include a target node identifier that identifies a target node to which the packet is to travel, and a direction identifier that identifies a direction to be traversed by the packet through the ring communication network. In some embodiments, the direction indicated by the direction identifier can be clockwise or counter-clockwise relative to a starting node from which the packet is to travel.

Abstract: A first network node generates a message to be transmitted to a second network node. The message can include a value that identifies a type of the operational session, an identifier of the first network node that can control transmission of packets used during the operational session, and a length of the identifier. Further, the first and second network nodes can operate in an operational session in which the second network node can detect a failure.

Abstract: A method is implemented by a network device to establish a two-way active measurement protocol (TWAMP) test session that supports use of a Network Time Protocol (NTP) timestamp format and a Precision Time Protocol Version 2 (PTPv2) timestamp format. The network device acts as a server that communicates with a control-client to establish a TWAMP test session between a sender and a reflector. The method includes sending a server greeting message to the control-client indicating timestamp formats that the reflector can set, receiving a set-up-response message from the control-client indicating timestamp formats that the sender can interpret, checking whether the sender supports the multiple timestamp format extensions to TWAMP, configuring the reflector to set timestamps in a format that the reflector can set and the sender can interpret if the sender supports multiple timestamp format extensions to TWAMP, and sending a server-start message to the control-client.

Abstract: Residence time is a variable part of the propagation delay of the packet. Information about the propagation delay for each transient node can be used as performance metric to calculate the Traffic Engineered route that can conform to delay and delay variation requirements. In an exemplary embodiment, a computing device uses special test packets to measure residence time. The computing device calculates routes to direct special test packets to one or more nodes. A node may calculate the residence time metric, such as a residence time variation (RTV), or residence time (RT) per ordered set of ingress and egress interfaces of the node. The computing device may also collect the residence time metric per test set from each node and may use this information to calculate the Test Engineered route.

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: Understanding the performance of a Service Function Chain (SFC) and how Virtual Network Functions (VNFs) contribute to the performance of the SFC can assist in the maintenance of services and quality of experience the VNFs are expected to provide. In an exemplary embodiment, a residence time of packets traversing a service function or virtual network function is measured. The residence time characterizes the processing delay a service function introduces into a network.

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: Non-ideal diodes have a non-zero resistance across a PN junction when the junction is forward biased. When a diode comprising a power supply has a voltage drop across the junction that exceeds a predetermined threshold, the threshold-exceeding voltage drop trips a comparator, the output of which controls a switch between a power supply and a load.

Abstract: A method is executed by a network device implementing a session-sender to perform a test to determine whether differentiated services code point (DSCP) and explicit congestion notification (ECN) are modified in a single test session in a forward direction and a reverse direction between the session-sender and a session-reflector, where multiple DSCP and ECN are tested using the single test session. The method includes determining a first initial forward DSCP and ECN, generating a first test packet including the first initial forward DSCP and ECN, and sending the first test packet to the session-reflector in the single test session. The method further includes determining a second initial forward DSCP and ECN, generating a second test packet including the second initial forward DSCP and ECN, and sending the second test packet to the session-reflector in the single test session.

Abstract: A method is executed by a network device implementing a control-client to configure a session- sender to perform a test to determine whether differentiated services code point (DSCP) and explicit congestion notification (ECN) are modified in a single test session in a forward direction and a reverse direction between the session-sender and a session-reflector. Multiple DSCP and ECN are tested using the single test session. The method includes receiving a server greeting message from a server including characteristics of the session-reflector, determining whether the session-reflector supports use of multiple DSCP in the single test session, setting a set-up- response message to indicate DSCP and ECN testing, and determining whether the session- reflector supports DSCP and ECN monitoring.

Abstract: This disclosure addresses improving the reliability of network connections between nodes, detection of failures of network connections, and the reduction of control packets exchanged between nodes. A second node may stop sending control packets to a first node causing a reduction in network throughput and increased network capacity. The network connection from the first node to the second may be of a first type and the connection from the second node to the first node may be of a second type. When a failure of the connection of the first type occurs, communication of the failure may be sent in a flag from the second node to the first node using the second type. A response to the flag received at the first node may be sent to the second node. The response may be sent using the second type of network connection because the first type failed.

Abstract: A method is implemented by a network device to establish a one-way active measurement protocol (OWAMP) test session to verify that a session-sender and session-reflector support a timestamp format extension including a Precision Time Protocol Version 2 (PTPv2) timestamp format. The PTPv2 timestamp format is to be utilized in place of a Network Time Protocol (NTP) timestamp format. The network device acts as a control-client that communicates with a server to establish an OWAMP test session between the session-sender and the session-receiver.

Abstract: A method is implemented by a network device to establish a one-way active measurement protocol (OWAMP) test session that supports use of a Network Time Protocol (NTP) timestamp format and a Precision Time Protocol Version 2 (PTPv2) timestamp format. The network device acts as a control-client that communicates with a server to establish an OWAMP test session between a sender and a receiver. The method includes receiving a server greeting message from the server indicating timestamp formats that the receiver can interpret, checking whether the receiver supports the multiple timestamp format extensions to OWAMP, configuring the sender to set timestamps in a format that the sender can set and the receiver can interpret if the receiver supports multiple timestamp format extensions to OWAMP, sending an extended set-up-response message to the server indicating a timestamp format that the sender can set and the receiver can interpret, and receiving a server-start message from the server.

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: 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.