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 IS-IS Configuration Guide. It enables users to access the latest IOS XR features and release information through a centralized, continuously updated resource.
YANG Data Models for IS-IS Features
Explore Cisco IOS XR's programmatic configuration and data collection using YANG data models for enhanced network automation.
Introduction to IS-IS
Introduces the IS-IS protocol, outlining core features, standards support, implementation restrictions, common use cases, and multi-instance deployment options for configuring and managing IS-IS in network environments.
Basic IS-IS Configuration
Outlines fundamental IS-IS configuration concepts, routing modes, and procedural steps for enabling and deploying IS-IS level 1 or level 2 routing within Cisco IOS XR environments.
IS-IS Topology Modes
Outlines IS-IS topology modes, including multitopology and single-topology IPv6 support, topology configuration procedures, interface association, and restrictions to optimize routing in complex network environments.
Route Management and Distribution
Outlines key concepts and procedures for managing and distributing network routes, including default and conditional route origination, IS-IS customization, routing policy configuration, route tagging, and BGP status tracking for optimized routing operations.
Metrics and SPF Calculation
Outlines IS-IS metric calculation strategies, auto-cost reference bandwidth implementation, interface bandwidth tracking, and SPF interval configuration procedures to optimize protocol performance and maintain accurate network topology computations.
Interface Management and Flooding Control
Outlines IS-IS interface types, adjacency configurations, neighbor setup, link grouping, flood control mechanisms, mesh groups, LSP flooding controls, and Layer 2 ACL implementation to enhance interface management and mitigate network flooding.
LSP Lifetimes
Explains LSP lifetime parameters, including maximum and minimum thresholds, as well as refresh intervals, to guide configuration and management of LSPs in network environments.
IS-IS Protection and Resiliency Enhancements
Outlines IS-IS protection and resiliency features, including nonstop forwarding, NSR, enhancements during OOR conditions, overload bit suppression, global weighted SRLG protection, and penalty mechanisms for link anomalies, with configuration and operational guidelines for robust network stability.
IS-IS Authentication and Key Management
Outlines IS-IS authentication methods and key management practices, covering the concepts and configuration steps required to secure IS-IS protocol operations with authentication and keychain mechanisms.
MPLS Traffic Engineering and IS-IS Integration
Outlines MPLS traffic engineering integration with IS-IS, including adjacency support, label distribution protocol synchronization, interarea tunnels, auto-configuration, and compatibility with graceful restart and nonstop forwarding for resilient network operations.
Fast Reroute and Load Balancing
Explains fast reroute concepts and load balancing strategies, covering IP and LDP fast reroute mechanisms, configuration of loop-free alternate paths, and unequal-cost multipath approaches for IS-IS environments to enhance network resilience and traffic distribution.
IS-IS Overload Bits, Avoidance, and Shutdown Modes
Describes IS-IS overload bit mechanisms, avoidance techniques, and shutdown modes, highlighting configuration procedures, operational considerations, and best practices for maintaining stable network routing and service continuity.
Multicast Features
Outlines multicast capabilities, focusing on multicast-intact functionality and topology support using IS-IS to enhance network performance and reliability for multicast traffic.
Management Information Base for IS-IS
Outlines the Management Information Base (MIB) for IS-IS, detailing its structure and role in facilitating effective network monitoring and protocol management.