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Telemetry & Monitoring

Monitoring an SRv6 network requires visibility into SRv6-specific state: SID tables, SR Policies, locator advertisements, and per-SID traffic counters. This page covers the telemetry and monitoring tools available.

What to Monitor in SRv6

Category What to Monitor Why
SID State Local SID table, SID counters (packets/bytes per SID) Verify SIDs are active and processing traffic
Locator Reachability IGP locator advertisement, BGP SRv6 SID reachability Detect locator withdrawal or advertisement issues
SR Policy State Active candidate path, segment list validity, BSID state Ensure TE policies are working as intended
Traffic Counters Per-SID, per-policy, per-VRF traffic statistics Capacity planning and anomaly detection
Path Performance Latency, jitter, loss per SRv6 path SLA monitoring and TE optimization
Errors SRH processing errors, SID not found, HMAC failures Security and configuration issues

Streaming Telemetry

Modern SRv6 deployments use model-driven streaming telemetry instead of SNMP polling. The router pushes data to a collector at configured intervals.

Architecture

graph LR
    R1[Router 1] -->|gRPC/gNMI| C[Telemetry Collector]
    R2[Router 2] -->|gRPC/gNMI| C
    R3[Router 3] -->|gRPC/gNMI| C
    C --> TS[(Time-Series DB)]
    TS --> G[Grafana / Dashboard]

Protocols

Protocol Description
gNMI gRPC Network Management Interface — subscribe to YANG model paths
gRPC Dial-Out Router initiates connection to collector
NETCONF XML-based configuration and state retrieval

YANG Models for SRv6

YANG models define the structure of SRv6 operational and configuration data. Key models:

IETF Standard Models

Model Scope IETF Reference
ietf-srv6-base SRv6 base configuration (locators, SIDs) draft-ietf-spring-srv6-yang
ietf-srv6-static Static SRv6 SID configuration draft-ietf-spring-srv6-yang
ietf-srv6-types SRv6 type definitions draft-ietf-spring-srv6-yang
ietf-segment-routing SR base model (shared by SR-MPLS and SRv6) RFC 9020

Key YANG Paths for SRv6 Monitoring

# SRv6 SID table (operational state)
/segment-routing/srv6/locators/locator[name]/sids/sid

# SRv6 SID counters
/segment-routing/srv6/locators/locator[name]/sids/sid/state/counters

# IS-IS SRv6 locator advertisements
/network-instances/network-instance/protocols/protocol[isis]/
  segment-routing/srv6/locators

# BGP SRv6 VPN routes
/network-instances/network-instance/protocols/protocol[bgp]/
  bgp/rib/afi-safis/afi-safi[vpnv4-unicast]/ipv4-unicast/routes

IPFIX for SRv6

IPFIX (IP Flow Information Export, RFC 7011) can export SRv6-specific flow data:

SRv6 Information Elements

IPFIX IE Description
ipv6ExtensionHeaders Indicates presence of SRH
srhSegmentsLeft Current Segments Left value
srhActiveSegment The active SID (current IPv6 DA)
srhSegmentList Full segment list from the SRH

Use Cases for IPFIX + SRv6

  • Traffic matrix per SRv6 policy or per VRF
  • Top talkers per SRv6 SID
  • Path utilization across segment lists
  • Anomaly detection — unexpected SRH patterns

Open-Source Monitoring Stack

A practical SRv6 monitoring stack using open-source tools:

┌──────────────────────────────────────────┐
│  Visualization: Grafana                   │
├──────────────────────────────────────────┤
│  Storage: Prometheus / InfluxDB           │
├──────────────────────────────────────────┤
│  Collection: Telegraf / gnmic / pmacct    │
├──────────────────────────────────────────┤
│  Transport: gNMI / IPFIX / BMP           │
├──────────────────────────────────────────┤
│  Source: Routers (IOS-XR, Junos, SONiC)  │
└──────────────────────────────────────────┘

Tools

Tool Role SRv6 Support
gnmic gNMI collector (subscribe to YANG paths) Full
Telegraf Metrics collection agent Via gNMI/SNMP plugins
pmacct IPFIX/NetFlow collector SRv6 IE support
Prometheus Time-series database Storage backend
InfluxDB Time-series database (alternative) Storage backend
Grafana Dashboarding and visualization Universal
GoBGP BGP monitoring (BMP) SRv6 NLRI

What to Alert On

Alert Condition Severity
SID removed from table SID count decreases unexpectedly Critical
Locator withdrawn from IGP IS-IS/OSPF stops advertising a locator Critical
SR Policy down No valid candidate path High
SRH error counter increasing Processing errors on a node High
Per-SID traffic drop to zero SID receiving no traffic when it should Medium
MTU exceeded drops Packets dropped due to encapsulation overhead Medium
HMAC validation failures Could indicate attack or misconfiguration High

Further Reading

References

  1. RFC 7011 - IPFIX Protocol Specification - Defines the IPFIX protocol for exporting flow information
  2. RFC 9020 - YANG Data Model for Segment Routing - Base YANG model for segment routing configuration and state
  3. draft-ietf-spring-srv6-yang - YANG data model specific to SRv6 configuration and operational state
  4. gnmic Documentation - Open-source gNMI collector for streaming telemetry