# Lab: Level-1 and Level-2 IS-IS Routing

DevFeed: [Lab: Level-1 and Level-2 IS-IS Routing](<https://devfeed.tech/articles/lab-level-1-and-level-2-is-is-routing-11121.md>)

Original publisher: [Read original article](<https://blog.ipspace.net/2025/01/isis-level-1-2/>)

Published: 2025-01-16T06:36:00Z

Content type: tutorial

Language: en

Sources: [ipSpace.net blog](<https://devfeed.tech/sources/ipspace-net-blog.md>)

Topics: [IS-IS](<https://devfeed.tech/topics/is-is.md>), [Routing (disambiguation)](<https://devfeed.tech/topics/routing.md>), [networking](<https://devfeed.tech/topics/networking.md>)

Tags: [is-is](<https://devfeed.tech/tags/is-is.md>), [netlab](<https://devfeed.tech/tags/netlab.md>), [routing](<https://devfeed.tech/tags/routing.md>)

## AI overview

This lab exercise explains the meaning and importance of using only level-2 routing in IS-IS deployments, compared with the common default of enabling both level-1 and level-2 routing.

## Source excerpt

One of the recipes for easy IS-IS deployments claims that you should use only level-2 routing (although most vendors enable level-1 and level-2 routing by default). What does that mean, and why does it matter? You'll find the answers in the Optimize Simple IS-IS Deployments lab exercise.