Abstract: This disclosure describes techniques for detecting and monitoring paths in a network. The techniques include causing a source node to generate probe packets to traverse a multi-protocol label switching (MPLS) network, for instance. In some examples, the probe packets include entropy values that correspond to individual equal-cost multi-path (ECMP) paths of the network. The probe packets may be received at an SDN controller from a sink node after traversing the network. Analysis of the probe packets allow path discovery and mapping of the entropy values to ECMP paths. The mapping of discovered paths may be used for optimization of network monitoring activities, including second subsequent probe packets over particular ECMP paths based on the mapped entropy values.

Abstract: Techniques for utilizing entropy labels of a Multiprotocol Label Switching (MPLS) label stack for performing monitoring operations (e.g., telemetry, performance measurement, OAM, etc.) without altering the MPLS label stack and/or packet path (e.g., ECMP path). The techniques may include determining, by a node of a network, to perform a monitoring operation associated with traffic that is to be sent along a path through the network. In some examples, the node may receive a packet that is to be sent along the path and encapsulate the packet with an MPLS header. The MPLS header may include an entropy label, entropy label indicator, or other label that is capable of carrying a flag indicating the monitoring operation to be performed. The flag may be carried in a TTL field or traffic class field of the label such that the MPLS label stack is not altered to trigger the monitoring operation.

Abstract: This disclosure describes techniques for detecting and monitoring paths in a network. The techniques include causing a source node to generate probe packets to traverse a multi-protocol label switching (MPLS) network, for instance. In some examples, the probe packets include entropy values that correspond to individual equal-cost multi-path (ECMP) paths of the network. The probe packets may be received at an SDN controller from a sink node after traversing the network. Analysis of the probe packets allow path discovery and mapping of the entropy values to ECMP paths. The mapping of discovered paths may be used for optimization of network monitoring activities, including second subsequent probe packets over particular ECMP paths based on the mapped entropy values.

Abstract: Techniques for utilizing entropy labels of a Multiprotocol Label Switching (MPLS) label stack for performing monitoring operations (e.g., telemetry, performance measurement, OAM, etc.) without altering the MPLS label stack and/or packet path (e.g., ECMP path). The techniques may include determining, by a node of a network, to perform a monitoring operation associated with traffic that is to be sent along a path through the network. In some examples, the node may receive a packet that is to be sent along the path and encapsulate the packet with an MPLS header. The MPLS header may include an entropy label, entropy label indicator, or other label that is capable of carrying a flag indicating the monitoring operation to be performed. The flag may be carried in a TTL field or traffic class field of the label such that the MPLS label stack is not altered to trigger the monitoring operation.

Abstract: In one aspect, a method for monitoring a Fast Re-Route (FRR) path between a source node (Node-S) and a destination node (Node-E) in a network, includes generating a discovery-probe at the source node (Node-S) to detect at least one node with an FRR indicator along the FRR path that includes a plurality of next available nodes. The method also includes upon the discovery probe reaching a first node with the FRR indicator, generating a primary probe configured to detect a primary path and a repair probe configured to detect a repair path. The method also includes in response to receiving the primary probe via the primary path and the repair probe via the repair path at the destination node, sending the primary probe and the repair probe back to the source node to monitor the FRR path between the source node and the destination node.

Abstract: Presented herein is an “In-situ OAM” (IOAM) mechanism that uses a Segment Routing-Multiprotocol Label Switching (SR-MPLS) IOAM segment identifier that can selectively collect IOAM data from “target” network nodes along a data packet path. In one embodiment, a method includes receiving, at a first network node in the SR-MPLS network, a data packet that includes an MPLS label stack comprising a plurality of segment identifiers (SIDs) associated with a plurality of network nodes. The MPLS label stack includes a first SID associated with the first network node. The method includes determining whether the first SID is an IOAM SID or a regular SID. Upon determining that the first SID is the IOAM SID, the method includes implementing an IOAM function at the first network node. Upon determining that the first SID is the regular SID, the method includes processing the data packet without implementing an IOAM function.

Abstract: Techniques for determine latency, loss, and liveness performance metrics associated with ECMP routes. The techniques may include determining that a TWAMP probe is to be sent from a first node to a second node along an equal-cost multipath ECMP route. In some examples, the first node may generate a packet for sending the TWAMP probe to the second node. The packet may include information specifying a forward path and reverse path to be traversed by the packet. In examples, the first node may send the packet to the second node along the ECMP route and subsequently receive the packet including telemetry data associated with the second node and a midpoint node of the ECMP route. Based at least in part on the telemetry data, the first node may determine a metric indicative of a performance measurement associated with the ECMP route.

Abstract: This disclosure describes techniques and mechanisms for performing passive measurement for combined one-way latency, packet loss metrics along with liveness detection using customer data packets ingested at a sink node in hardware for Level 2 and Level 3 VPN services. The customer data packets are sampled and copied for measurement either at source node or sink node. The duplicated measurement packet headers are punted based on the IPV6 destination option type to hardware analytics engine at sink node for analytics that populates histogram bins using the timestamps from the packets. Using the transmitted packets during a period, and received packets in all the bins, packet loss is measured. Based on the packets received status, liveness state is detected by the sink node and notified to the source node.

Abstract: Techniques for optimizing technologies related to network path tracing and network delay measurements are described herein. Some of the techniques may include using an IPv6 header option and/or segment identifier field of a segment list or a TLV of a segment routing header as a telemetry data carrier. The techniques may also include using an SRv6 micro-segment (uSID) instruction to indicate to a node of a network that the node is to perform one or more path tracing actions and encapsulating the packet and forward. Additionally, the techniques may include using short interface identifiers corresponding to node interfaces to trace a packet path through a network. Further, the techniques may include using short timestamps to determine delay measurements associated with sending a packet through a network. In various examples, the techniques described above and herein may be used with each other to optimize network path tracing and delay measurement techniques.

Abstract: Disclosed are systems, apparatuses, methods, and computer-readable media to implement circuit-style network with co-routed bidirectional network paths. A method includes receiving a request for a circuit policy between a source node and a destination node, the circuit policy defining a co-routed bidirectional policy between the source node and the destination node; requesting a path compute service to identify a path between the source node and the destination node that satisfies the circuit policy through a first network; receiving a path identifying a first set of network nodes that satisfy the circuit policy; configuring each node in the first set of network nodes within the first network with the circuit policy; and establishing a connection using the path that satisfies the circuit policy between the source node and the destination node.

Abstract: Techniques for optimizing technologies related to network path tracing and network delay measurements are described herein. Some of the techniques may include using an IPV6 header option and/or segment identifier field of a segment list or a TLV of a segment routing header as a telemetry data carrier. The techniques may also include using an SRv6 micro-segment (uSID) instruction to indicate to a node of a network that the node is to perform one or more path tracing actions and encapsulating the packet and forward. Additionally, the techniques may include using short interface identifiers corresponding to node interfaces to trace a packet path through a network. Further, the techniques may include using short timestamps to determine delay measurements associated with sending a packet through a network. In various examples, the techniques described above and herein may be used with each other to optimize network path tracing and delay measurement techniques.

Abstract: Techniques for optimizing technologies related to network path tracing and network delay measurements are described herein. Some of the techniques may include using an IPv6 header option and/or segment identifier field of a segment list or a TLV of a segment routing header as a telemetry data carrier. The techniques may also include using an SRv6 micro-segment (uSID) instruction to indicate to a node of a network that the node is to perform one or more path tracing actions and encapsulating the packet and forward. Additionally, the techniques may include using short interface identifiers corresponding to node interfaces to trace a packet path through a network. Further, the techniques may include using short timestamps to determine delay measurements associated with sending a packet through a network. In various examples, the techniques described above and herein may be used with each other to optimize network path tracing and delay measurement techniques.

Abstract: Techniques for optimizing technologies related to network path tracing and network delay measurements are described herein. Some of the techniques may include using an IPv6 header option and/or segment identifier field of a segment list or a TLV of a segment routing header as a telemetry data carrier. The techniques may also include using an SRv6 micro-segment (uSID) instruction to indicate to a node of a network that the node is to perform one or more path tracing actions and encapsulating the packet and forward. Additionally, the techniques may include using short interface identifiers corresponding to node interfaces to trace a packet path through a network. Further, the techniques may include using short timestamps to determine delay measurements associated with sending a packet through a network. In various examples, the techniques described above and herein may be used with each other to optimize network path tracing and delay measurement techniques.

Abstract: Systems and techniques are provided for implementing multiprotocol label switching (MPLS) header extensions. In some examples, a method can include, receiving, by a router of a MPLS network, a data packet. In some aspects, the method can include adding, by the router of the MPLS network, at least one entry to an MPLS stack of the data packet, wherein the at least one entry includes an MPLS extension indicator (MEI) that is associated with at least one of an in-stack extension header presence indicator (IPI) and a bottom-of-stack extension header presence indicator (BPI). In some examples, the method can include adding, based on the IPI and the BPI, at least one of an in-stack extension header and a bottom-of-stack extension header to the MPLS stack of the data packet.

Abstract: In one aspect, a method for monitoring a Fast Re-Route (FRR) path between a source node (Node-S) and a destination node (Node-E) in a network, includes generating a discovery-probe at the source node (Node-S) to detect at least one node with an FRR indicator along the FRR path that includes a plurality of next available nodes. The method also includes upon the discovery probe reaching a first node with the FRR indicator, generating a primary probe configured to detect a primary path and a repair probe configured to detect a repair path. The method also includes in response to receiving the primary probe via the primary path and the repair probe via the repair path at the destination node, sending the primary probe and the repair probe back to the source node to monitor the FRR path between the source node and the destination node.

Abstract: Systems and methods for validating a hardware path capability are provided. The method includes generating, at an ingress node of a network, an operations, administration and maintenance (OAM) probe packet having an OAM bit set associated with validating the hardware path capability, wherein the OAM probe packet comprises a plurality of features; indicating, by each respective intermediate node of a plurality of intermediate nodes in the network along a network path and as instructed by the OAM bit set, whether the respective intermediate node can support the respective feature of the plurality of features; generating, at an egress node associated with the network path, a report regarding whether the plurality of intermediate nodes can support each respective feature of the plurality of features within the OAM probe packet; and determining, based on the report, whether to enable customer traffic implementing the plurality of features along the network path.

Abstract: A method is performed by a network controller that is configured to control routers configured to forward a multicast flow downstream from a first hop router that is a root of a multicast tree formed by the routers to last hop routers that terminate branches of the multicast tree, respectively. The method includes collecting operational configuration information from the routers and constructing a topological view of the multicast tree based on the operational configuration information; causing the routers to forward multicast probes downstream from the first hop router along all of the branches toward the last hop routers to trace the multicast tree; receiving, from particular ones of the last hop routers that received the multicast probes, indications that the multicast probes were received; and detecting failures in the multicast tree based on the indications and the topological view.

Abstract: Systems and techniques are provided for implementing multiprotocol label switching (MPLS) header extensions. In some examples, a method can include, receiving, by a router of a MPLS network, a data packet. In some aspects, the method can include adding, by the router of the MPLS network, at least one entry to an MPLS stack of the data packet, wherein the at least one entry includes an MPLS extension indicator (MEI) that is associated with at least one of an in-stack extension header presence indicator (IPI) and a bottom-of-stack extension header presence indicator (BPI). In some examples, the method can include adding, based on the IPI and the BPI, at least one of an in-stack extension header and a bottom-of-stack extension header to the MPLS stack of the data packet.

Abstract: Systems, methods, and computer-readable media are disclosed for validating multiple paths used for routing network traffic in a network. In one aspect, a network controller can identify one or more intermediate nodes on each of multiple paths in a network, wherein the multiple paths begin at a first network node and end at a last network node. The network controller can further generate a data packet with a label at the first network node, forward the test data packet from the first network node, along each of the one or more intermediate nodes, to the last network node, and perform a data plane validation process for validating packet forwarding from the first network node to the last network node based on the label(s) by determining if a number of the multiple paths equals to a number of packets received at the last network node.

Abstract: In one embodiment, a service chain data packet is instrumented as it is communicated among network nodes in a network providing service-level and/or networking operations visibility. The service chain data packet includes a particular header identifying a service group defining one or more service functions, and is a data packet and not a probe packet. A network node adds networking and/or service-layer operations data to the particular service chain data packet, such as, but not limited to, in the particular header. Such networking operations data includes a performance metric or attribute related to the transport of the particular service chain packet in the network. Such service-layer operations data includes a performance metric or attribute related to the service-level processing of the particular service chain data packet in the network.