Provides comprehensive instructions for configuring and managing routing features on the platform, covering RIB and RIP operation, routing policy definition and attachment, static routing, unequal-cost load balancing, bidirectional forwarding detection, and fast reroute, while detailing feature behaviors, policy application points, and verification workflows.
Getting Started
This cumulative guide provides a single, continuously updated version that includes all the latest IOS XR features and release updates. It simplifies your experience by letting you bookmark one link and access the complete guide, instead of navigating through multiple release-specific versions.
Specific changes or updates tied to individual releases are clearly called out within the relevant sections. For a list of features introduced in a specific release, refer to the Release Notes.
The table lists the release numbers for which this document has been updated since its initial publication.
| Date | Summary |
|---|---|
| June 2026 |
First published for Release 26.2.1 |
Getting Started
Outlines the release history and update summary for the Routing Configuration Guide. It enables users to access the latest IOS XR features and release information through a centralized, continuously updated resource.
Implement and Monitor RIB
Explains how RIB stores best routes from multiple protocols, selects the overall preferred routes by administrative distance, and supports forwarding and monitoring across the system.
Routing Information Protocol
Explains how RIP operates in small autonomous systems, including route exchange, version support, route selection, timers, redistribution, policies, authentication, and RIPng configuration.
Routing Policy Language
Explains how Routing Policy Language supports modular policy creation, reusable components, route matching, attribute modification, validation, execution behavior, and aggregation control for routing policies.
Apply and Manage Routing Policies
Explains how to attach, validate, modify, and edit routing policies across supported protocol contexts, including BGP, OSPF, OSPFv3, and IS-IS attach points.
Policy Based Routing
Describes how policy-based routing enables routing decisions based on parameters beyond destination IP address, allowing granular traffic control and optimization.
Implementing Static Routes
Explains how to configure and manage static routes, including route types, VRF use, multicast routing, cross address-family routing, scalability limits, and load-balancing behavior through configuration examples.
Implementing UCMP
Explains how unequal-cost multipath load balancing distributes traffic proportionally across paths with different costs, and describes UCMP concepts, weighted forwarding behavior, BGP and IS-IS configuration methods, scaling enhancements, and verification of normalized load-sharing in the forwarding table.
Bidirectional Forwarding Detection
Explains how BFD provides low-overhead, fast failure detection between adjacent forwarding engines across different media and protocol layers.
Implementing Fast Reroute Loop-Free Alternate
Explains how LFA-based fast reroute provides rapid traffic recovery through local and remote backup paths, repair path selection, and protocol support in IS-IS and OSPF.
Flexible Algorithm in IP Networks
Explains how IGP flexible algorithm computes constraint-based IPv4 and IPv6 paths so different traffic types can follow customized routes instead of the default least-cost path.