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Nokia SR OS NRS I lab 12 of 14

Troubleshooting the core

Four faults from a bad maintenance night: find and fix them from the bottom up, through OSPF, LDP and RSVP-TE.

Run this lab

It needs Standard: its 3 nodes are set to 6 vCPU and 14,400 MB in total.

In your workspace: Shared, then Nokia SR OS NRS I guided labs, then 12 - Troubleshooting the core

Run it on Standard from £5 a day

The free demo can’t run it: it has 6 vCPU and 8 GB, and this lab’s nodes need 6 vCPU and 14,400 MB together. Every lab plan includes every guided lab.

Level
Advanced
Time
About 60 minutes
Nodes need
6 vCPU, 14,400 MB
Smallest plan
Standard

The scenario

Last night's maintenance at Brenton and Cardew didn't go well. It's Monday morning, and the service desk has passed you one line: "Ashby can't reach Cardew, and the LSP to Cardew is down." The engineer who did the work is on leave, and there's no change record.

The network should look like this: OSPF area 0 across all three routers, LDP on every link, and RSVP-TE carrying the LSP R1-TO-R3. There are four separate faults, spread across R2 and R3. Find each one, fix it, and work out what told you.

DeviceInterfacePortAddressConnects to
R1system-10.255.0.1/32
R1to-R21/1/c1/110.0.12.1/30R2
R2system-10.255.0.2/32
R2to-R11/1/c1/110.0.12.2/30R1
R2to-R31/1/c2/110.0.23.1/30R3
R3system-10.255.0.3/32
R3to-R21/1/c1/110.0.23.2/30R2

What you’ll practise

  • Work through the layers from port to LSP
  • Spot OSPF timer and MTU mismatches
  • Find a missing LDP interface
  • Read why an LSP fails CSPF

The tasks

  1. Work from the bottom up
  2. Restore OSPF between R1 and R2
  3. Restore OSPF between R2 and R3
  4. Restore the LDP tunnel
  5. Restore the LSP

The Lab Tasks pane has the scenario, these tasks, the checks to run, hints and the full solution.

Topology and devices

The network as it opens in EVE-NG, drawn from the lab’s own canvas, and the image each node runs.

Topology of Troubleshooting the core3 nodes, 2 links. Every link is listed as text below the diagram.R1R2R3p1/1/1p1/1/1p1/1/2p1/1/1
3 nodes, with the interface names each link uses. On a narrow screen, scroll the diagram sideways.
Every link, as text
  • R1 p1/1/1 to R2 p1/1/1
  • R2 p1/1/2 to R3 p1/1/1
Nodes in Troubleshooting the core, with the image each runs and the vCPU and RAM it’s set to
NodeDeviceImage in Add NodeSet to
R1Nokia Integrated router (VSR NG template)timos-ng-21.10.R12 vCPU, 4,800 MB
R2Nokia Integrated router (VSR NG template)timos-ng-21.10.R12 vCPU, 4,800 MB
R3Nokia Integrated router (VSR NG template)timos-ng-21.10.R12 vCPU, 4,800 MB

How to open this lab

  1. Sign in to your workspace at lab.cloudlabbox.com.

  2. In File Manager, open Shared, then the folder Nokia SR OS NRS I guided labs.

  3. Open 12 - Troubleshooting the core and start its nodes, then open Lab Tasks for the scenario and the steps.

The lab is read-only. You can start the nodes and configure the devices, but changes to the topology can’t be saved. To change it, rebuild it in your own folder.

More Nokia SR OS NRS I labs

All Nokia SR OS NRS I labs

Related labs in other courses

CloudLabBox is independent of Nokia. The lab follows exam topics and isn’t vendor training material; vendor names identify the exams and the images in the workspace.