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1. Overview

This document defines a device YANG data model [RFC7950] that can be used to manage IS-IS extensions for Segment Routing (SR) [RFC8667] over the MPLS data plane. It is an augmentation to the IS-IS YANG data model [RFC9130].

1.1. Tree Diagrams

This document uses the graphical representation of a data model as defined in [RFC8340].

YANG Module Overview

The ietf-isis-sr-mpls data model defines both the data nodes to configure IS-IS SR MPLS extensions and the additions to the IS-IS Link State Protocol Data Units (LSPs) necessary to support MPLS SR.

Key Features

This YANG module provides the following main features:

  1. Segment Routing Activation - Enable and configure IS-IS segment routing functionality
  2. Mapping Server Policy - Configure Segment Routing Mapping Server (SRMS) policy
  3. IP Fast Reroute - Configure segment routing-based fast reroute mechanisms, including Topology Independent Loop-Free Alternate (TI-LFA)

Module Dependencies

The IS-IS SR MPLS YANG module requires support for:

  • Base SR Module [RFC9020] - Defines global SR management independent of any specific routing protocol configuration
  • IS-IS Base Model [RFC9130] - Defines the basic IS-IS configuration and state

Data Node Organization

This module defines the following data nodes:

  • Configuration Nodes - Used to configure IS-IS SR MPLS extensions
  • State Nodes - Provide additions to the IS-IS LSPs necessary to support MPLS SR

Through this YANG model, network administrators can configure and manage segment routing functionality in IS-IS networks using a standardized approach, enabling more flexible and efficient traffic engineering.