CloudLabBox
Try the free demo

HCIA-Datacom lab 20 of 22

Troubleshooting a switched network

A colleague's change left the Northwind floor half broken. Three tickets, four hidden faults: you work from symptoms to causes with a layered method, using display commands rather than guesses, and fix each fault without breaking anything else.

Run this lab

It needs Standard: its 6 nodes are set to 9 vCPU and 9,216 MB in total.

In your workspace: Shared, then HCIA-Datacom H12-811 guided labs, then 20 - Troubleshooting a switched network

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 9 vCPU and 9,216 MB together. Every lab plan includes every guided lab.

Level
Advanced
Time
About 60 minutes
Nodes need
9 vCPU, 9,216 MB
Smallest plan
Standard

The scenario

Last night a contractor "tidied up" the configuration of Northwind's switches. This morning the helpdesk has three tickets:

  • Ticket 1: PC1 (Finance, on SW2) can't reach anything, not even its gateway.
  • Ticket 2: PC2 (Sales, on SW3) can't reach its gateway.
  • Ticket 3: PC3 (Finance, on SW3) can't reach its gateway either, though it worked yesterday.

The design hasn't changed:

  • Finance is VLAN 10 (192.168.10.0/24) and Sales is VLAN 20 (192.168.20.0/24). Both gateways are .254, on SW1's VLANIFs.
  • SW1 and SW2 are joined by Eth-Trunk1 in LACP mode. Today it has one member, GE1/0/2; a second link is on order, and the bundle is ready for it.
  • SW1 and SW3 are joined by an 802.1Q trunk on GE1/0/1 carrying VLANs 10 and 20 (not VLAN 1).
  • The PCs' own settings are correct: don't change them.

There are four faults in total. Some tickets have more than one cause.

What you’ll practise

  • Apply a structured troubleshooting method: define the problem, gather facts, isolate by layer, fix, verify
  • Find VLAN membership, trunk allowed-list and Eth-Trunk negotiation faults from display output
  • Spot a gateway subnet-mask mistake from ARP and routing behaviour
  • Document each fault and its fix

The tasks

  1. Load the broken network
  2. Ticket 2 (PC2, Sales)
  3. Ticket 3 (PC3, Finance on SW3)
  4. Ticket 1 (PC1, Finance on SW2)
  5. Prove everything and write it up

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 a switched network6 nodes, 5 links. Every link is listed as text below the diagram.SW1SW2SW3PC1PC2PC3GE1/0/10eth0GE1/0/11eth0GE1/0/10eth0GE1/0/2GE1/0/2GE1/0/1GE1/0/1
6 nodes, with the interface names each link uses. On a narrow screen, scroll the diagram sideways.
Every link, as text
  • SW1 GE1/0/2 to SW2 GE1/0/2
  • SW1 GE1/0/1 to SW3 GE1/0/1
  • SW2 GE1/0/10 to PC1 eth0
  • SW3 GE1/0/11 to PC2 eth0
  • SW3 GE1/0/10 to PC3 eth0
Nodes in Troubleshooting a switched network, with the image each runs and the vCPU and RAM it’s set to
NodeDeviceImage in Add NodeSet to
SW1Huawei CloudEngine CE6800huaweice6800-bundled2 vCPU, 2,048 MB
SW2Huawei CloudEngine CE6800huaweice6800-bundled2 vCPU, 2,048 MB
SW3Huawei CloudEngine CE6800huaweice6800-bundled2 vCPU, 2,048 MB
PC1VPCS hostBuilt in to EVE-NGCounted as 1 vCPU, 1,024 MB
PC2VPCS hostBuilt in to EVE-NGCounted as 1 vCPU, 1,024 MB
PC3VPCS hostBuilt in to EVE-NGCounted as 1 vCPU, 1,024 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 HCIA-Datacom H12-811 guided labs.

  3. Open 20 - Troubleshooting a switched network 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 HCIA-Datacom labs

All HCIA-Datacom labs

Related labs in other courses

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