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SRv6 and SRv6-TE Traffic Sensor Telemetry

Segment Routing over IPv6 (SRv6) telemetry support introduces a powerful mechanism for monitoring and optimizing network performance. By leveraging the native SRv6 data model, you can integrate telemetry tools that provide comprehensive insights into network traffic. These insights are gathered using streaming XPath from the SRv6 Manager and rpd, which collect and transmit detailed traffic statistics. This capability is essential for maintaining high levels of network performance and security, as it allows you to monitor real-time traffic patterns, detect anomalies, and respond to potential issues promptly.

The telemetry support for SRv6 includes the integration of a unified data model for both SRv6 and SRv6 TE tunnels. This standardization simplifies the management and monitoring of different tunneling technologies within your network. Although the current implementation focuses on SRv6 TE tunnels, the groundwork is laid for broader support in future updates. The data model ensures consistency and ease of use, making it simpler to configure and manage telemetry across various network segments.

To enable effective traffic monitoring, traffic sensors are installed on routes and next hops within the rpd. These sensors are mapped to ISIS and SRTE sensors, allowing the Packet Forwarding Engine (PFE) to collect and stream traffic statistics. This integration provides you with detailed visibility into network performance, enabling proactive management and troubleshooting. By monitoring traffic at a granular level, you can optimize routing decisions, improve network efficiency, and enhance overall operational reliability.

Following are some of the functionalities of SRv6 in telemetry:

  • Traffic Statistics telemetry for IGP (ISIS Only) Routes / NextHops: Following is the list of PFE sensors, which are installed by IS-IS based upon the newly introduced configuration commands and streamed by PFE.

    Table 1: Traffic Statistics telemetry for IGP Routes or NextHops.
    Sensor Path Description
    /state/routing-instances/routing-instance[name]/protocols/source-packet-routing/srv6/remote-locators/remote-locator[address]/counters/in-pkts/state/routing-instances/routing-instance[name]/protocols/source-packet-routing/srv6/remote-locators/remote-locator[address]/counters/in-octets This sensor path is applicable for PFE sensor for Remote SRv6 locator routes in INET6.0 RT.
    /state/routing-instances/routing-instance[name]/protocols/source-packet-routing/srv6/remote-locators/remote-locator[address]/counters/out-pkts/state/routing-instances/routing-instance[name]/protocols/source-packet-routing/srv6/remote-locators/remote-locator[address]/counters/out-octets This sensor path is applicable for PFE sensor for Remote SRv6 Locator Route TCNH Gateway in INET6.3 RT.
  • Support for Uniformed Native Data Model for SR-TE: This feature includes a model tree for both colored and uncolored policies. Only SRv6-TE FIB Xpaths (traffic counter) with ingress counters are supported for both tunnel types. SRv6 TE traffic counter Xpaths streaming is platform-dependent, applicable only to JUNOS MX platforms. At PFE, stats accounting occurs before policy application, supporting only ingress counters. SRv6-TE sensors support only the DEFAULT instance.

  • Colored SRv6-TE per policy ingress counters: The supported counters are listed here-

    Table 2: Colored SRv6-TE per-policy Ingress Counters
    Sensor Path Description

    /state/routing-instances/routing-instance[name]/protocols/source-packet-routing/te-policies/te-policy[color endpoint]/counters/srv6/in-bytes

    This sensor path is applicable for per-policy level PFE sensors pfor SRv6 SR-TE route TCNH gateway in junos-rti table.
    /state routing-instances/routing-instance[name]/protocols/source-packet-routing/te-policies/te-policy[color endpoint]/counters/srv6/in-pkts This sensor path is applicable for ingress SRv6 traffic.
    Note that when per-policy counters are streamed, the values will be cumulative of all the candidate-paths of that policy.
  • Colored SRv6-TE per path ingress counters: The supported counters are listed here-

    Table 3: Colored SRv6-TE per-path Ingress Counters
    Sensor Path Description

    /state/routing-instances/routing-instance[name]/protocols/source-packet-routing/te-policies/te-policy[color endpoint]/candidate-paths/candidate-path[protocol-origin originator-asn originator-address discriminator]/segment-lists/segment-list[segment-id]/counters/in-bytes

    This sensor path is applicable for per-path level PFE sensors for SRv6 SR-TE route TCNH gateway in junos-rti table.
    /state/routing-instances/routing-instance[name]/protocols/source-packet-routing/te-policies/te-policy[color endpoint]/candidate-paths/candidate-path[protocol-origin originator-asn originator-address discriminator]/segment-lists/segment-list[segment-id]/counters/in pkts This sensor path is applicable for ingress SRv6 traffic.
  • Uncolored SRv6-TE per tunnel ingress counters: The supported counters are listed here-

    Table 4: Uncolored SRv6-TE per-tunnel Ingress Counters
    Sensor Path Description
    /state/routing-instances/routing-instance[name]/protocols/source-packet-routing/uncolored-te-tunnels/uncolored-te-tunnel[name]/counters/in-bytes This sensor path is applicable for per-policy level PFE sensors for SRv6 SRTE uncolored route TCNH gateway in inet6.3 table.
    /state/routing-instances/routing-instance[name]/protocols/source-packet-routing/uncolored-te-tunnels/uncolored-te-tunnel[name]/counters/in-pkts This sensor path is applicable for ingress SRv6 traffic.
  • Uncolored SRv6-TE per path ingress counters: The supported counters are listed here-

    Table 5: Uncolored SRv6-TE per-path Ingress Counters
    Sensor Path Description
    /state/routing-instances/routing-instance[name]/protocols/source-packet-routing/uncolored-te-tunnels/uncolored-te-tunnel[name]/segment-lists/segment-list[segment-id]/counters/in-bytes This sensor path is applicable for per-path level PFE sensors for SRv6 SRTE uncolored route TCNH gateway in inet6.3 table.
    /state/routing-instances/routing-instance[name]/protocols/source-packet-routing/uncolored-te-tunnels/uncolored-te-tunnel[name]/segment-lists/segment-list[segment-id]/counters/in-pkts This sensor path is applicable for ingress SRv6 traffic.

Benefits of SRv6 and SRv6-TE Traffic Sensor Telemetry

  • Enhances network performance monitoring through detailed traffic statistics, allowing you to track packet and byte counts for both ingress and egress traffic.

  • Provides granular insights into SRv6 traffic via traffic sensors for IS-IS SRv6 routes and next-hops, facilitating effective network analysis and optimization.

  • Supports targeted troubleshooting and optimization by offering ingress counters for both colored and uncolored SRv6-TE policies and paths, enabling precise traffic performance analysis.

  • Improves operational efficiency and decision-making through the integration of native YANG data models for SRv6 Base and SRv6-TE, allowing for seamless telemetry data streaming and interpretation.

Limitations

  • SR-TE recommends using unique tunnel names for different sources such as Static, PCEP, or BGP-SRTE. Sharing names will result in shared stats.

  • Sensor values do not retain during the NSR/GR phase. They change after NSR/GR.