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MikroTik MTCTCE lab 7 of 8

Troubleshooting: queues that don't match

Fernvale's Westbrook office has shaping configured, and none of it works: the guest kiosk downloads at full speed and the accounts PC ignores its class. Find four planted faults, a stray catch-all simple queue, a swapped upload/download pair, a packet mark that doesn't match its queue, and a queue tree on the wrong interface, by measuring and reading counters rather than guessing.

Run this lab

It needs Lite: its 4 nodes are set to 4 vCPU and 1,024 MB in total. That fits the free demo too.

In your workspace: Shared, then MikroTik MTCTCE RouterOS v7 guided labs, then 07 - Troubleshooting - queues that dont match

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Level
Advanced
Time
About 60 minutes
Nodes need
4 vCPU, 1,024 MB
Smallest plan
Lite

The scenario

Fernvale's Westbrook office router was configured by a contractor, and the shaping doesn't work. The design was simple:

  • the guest kiosk (KIOSK, 192.168.50.11) gets 128k up and 256k down, with a simple queue;
  • the accounts PC (ACCOUNTS, 192.168.50.12) gets 384k down (128k guaranteed), with a mangle mark and a queue tree on the office's 768k downlink.

In practice both download at full speed. There are four faults. Find each one by measuring and reading counters, fix it, and measure again.

DeviceAddressRole
NET192.0.2.1/30the Internet, bandwidth-test server
WESTBROOKether1 192.0.2.2/30 (uplink) · ether2 192.168.50.1/24 (office)the shaping router
KIOSK · ACCOUNTS192.168.50.11 · 192.168.50.12RouterOS routers playing the two PCs

What you’ll practise

  • Troubleshoot shaping by measuring first, then reading queue and mangle counters
  • Find simple queues that never match because of the first-match order
  • Spot swapped upload/download limits
  • Trace a packet mark from mangle to the queue that should use it
  • Check that a queue tree is attached where the traffic actually leaves

The tasks

  1. Measure first
  2. The kiosk's simple queue
  3. The accounts PC's queue tree
  4. Measure again

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 - queues that dont match4 nodes and 1 network, 4 links. Every link is listed as text below the diagram.NETWESTBROOKKIOSKACCOUNTSOfficeether2ether1ether1ether1ether1
4 nodes and 1 network, with the interface names each link uses. On a narrow screen, scroll the diagram sideways.
Every link, as text
  • NET ether1 to WESTBROOK ether1
  • WESTBROOK ether2 to Office (network)
  • KIOSK ether1 to Office (network)
  • ACCOUNTS ether1 to Office (network)
Nodes in Troubleshooting: queues that don't match, with the image each runs and the vCPU and RAM it’s set to
NodeDeviceImage in Add NodeSet to
NETMikroTik RouterOSmikrotik-7.14.21 vCPU, 256 MB
WESTBROOKMikroTik RouterOSmikrotik-7.14.21 vCPU, 256 MB
KIOSKMikroTik RouterOSmikrotik-7.14.21 vCPU, 256 MB
ACCOUNTSMikroTik RouterOSmikrotik-7.14.21 vCPU, 256 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 MikroTik MTCTCE RouterOS v7 guided labs.

  3. Open 07 - Troubleshooting - queues that dont match 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.

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