Intro to ISIS

ISIS is a Linkstate Database protocol that relies on the Dykstra Algorithm to calculate the shortest path across the network. Every ISIS router advertises LSAs (Link State Advertisements) propagated throughout the network. These LSAs enable an ISIS router to carry Traffic Engineering attributes when combined with Segment Routing and provide Fast Reroute capabilities in conjunction with SR. This lab does not explore Segment Routing, but this section will familiarize the user with the ISIS database.

The purpose of this lab is to provide a hands-on lab environment that will familiarize the user with the basic routing configuration of ISIS running on Cisco routers. The lab assumes the user has little or no knowledge of ISIS. The exercises in this lab are designed to guide the user through the basic IP addressing and ISIS setup on Cisco XRv9000 virtual routers. The lab exercises are based on the basic ISIS configuration and commands available in Cisco IOS XR.

This lab guide will walk the user through the basic configuration of ISIS. The lab demonstrates how ISIS is configured and deployed on Cisco IOS XR using IOS XRv9000 instances in vCloud. This environment utilizes six IOS XRv9000 v7.1.1 routers.

This document is composed of the following chapters:

• Introduction
• Physical Topology
• Lab Access Details
• IP Addressing
• ISIS
• Conclusion

Six Cisco IOS XRv9000 routers running 7.1.1