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MikroTik MTCTCE lab 5 of 8

Queue types: FIFO, SFQ, RED, fq-codel and CAKE against bufferbloat

Riverside's staff say the Internet is fine until someone downloads, then calls and games lag by seconds. Reproduce the problem, bufferbloat, with a big FIFO queue, measure the ping times under load, and fix it with the modern queue types in RouterOS 7: fq-codel in a queue tree, then CAKE on the interface, which shapes, separates flows and controls delay on its own. Meet SFQ and RED on the way.

Run this lab

It needs Lite: its 3 nodes are set to 3 vCPU and 768 MB in total. That fits the free demo too.

In your workspace: Shared, then MikroTik MTCTCE RouterOS v7 guided labs, then 05 - Queue types - FIFO SFQ RED fq-codel and CAKE against bufferbloat

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Level
Advanced
Time
About 60 minutes
Nodes need
3 vCPU, 768 MB
Smallest plan
Lite

The scenario

Riverside's downlink is shaped to 512k (small numbers because of the CHR licence; lab 2 explains). Staff report that everything is fine until someone starts a download; then calls stutter and remote desktops lag by seconds. That's bufferbloat: a queue so big that packets wait in it for seconds. You'll reproduce it, measure it, and cure it with the right queue type.

DeviceAddressRole
NET192.0.2.1/30the Internet, bandwidth-test server
RIVERSIDEether1 192.0.2.2/30 · ether2 192.168.50.1/24the office router
PC1192.168.50.11a RouterOS router playing a staff PC

What you’ll practise

  • Explain FIFO, SFQ, RED, fq-codel and CAKE and what queue size does to delay
  • Create queue types and attach them to a queue tree leaf or an interface
  • Measure latency under load with a background download and ping
  • Shape and manage a link with CAKE alone

The tasks

  1. The queue types
  2. Reproduce bufferbloat
  3. Cure it with fq-codel
  4. SFQ and RED
  5. CAKE on the interface, no tree needed

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 Queue types - FIFO SFQ RED fq-codel and CAKE against bufferbloat3 nodes, 2 links. Every link is listed as text below the diagram.NETRIVERSIDEPC1ether1ether1ether2ether1
3 nodes, with the interface names each link uses. On a narrow screen, scroll the diagram sideways.
Every link, as text
  • NET ether1 to RIVERSIDE ether1
  • RIVERSIDE ether2 to PC1 ether1
Nodes in Queue types: FIFO, SFQ, RED, fq-codel and CAKE against bufferbloat, 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
RIVERSIDEMikroTik RouterOSmikrotik-7.14.21 vCPU, 256 MB
PC1MikroTik 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 05 - Queue types - FIFO SFQ RED fq-codel and CAKE against bufferbloat 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.