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MikroTik MTCTCE lab 4 of 8

PCQ: fair sharing and per-subscriber caps with one queue

Fernvale's Riverside wireless access point serves many subscribers through one backhaul. Instead of a queue per subscriber, use PCQ: one simple queue that splits the link fairly between whoever is active, caps each subscriber at their plan's rate, and needs no change when a subscriber is added. Measure the sharing with three subscribers at once.

Run this lab

It needs Lite: its 5 nodes are set to 5 vCPU and 1,280 MB in total. That fits the free demo too.

In your workspace: Shared, then MikroTik MTCTCE RouterOS v7 guided labs, then 04 - PCQ - fair sharing and per-subscriber caps with one queue

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Level
Intermediate
Time
About 50 minutes
Nodes need
5 vCPU, 1,280 MB
Smallest plan
Lite

The scenario

Fernvale's Riverside wireless access point (AP) connects subscribers to the Internet over one backhaul. Every subscriber is on the same plan: up to 320k down and 128k up. The backhaul is shaped to 768k down (lab 2 explains the small numbers). With a simple queue per subscriber you'd need a queue for every new customer, and nothing would stop four subscribers' plans adding up to more than the backhaul. PCQ solves both with one queue.

DeviceAddressRole
NET192.0.2.1/30the Internet, bandwidth-test server
APether1 192.0.2.2/30 · ether2 192.168.50.1/24the access point
SUB1 · SUB2 · SUB3192.168.50.11 · .12 · .13subscriber CPEs (RouterOS)

What you’ll practise

  • Explain how PCQ builds a sub-queue per classifier value
  • Create PCQ types for download and upload with the right classifiers
  • Use pcq-rate=0 for equal sharing and a pcq-rate for a per-subscriber cap
  • Size a PCQ with pcq-limit and pcq-total-limit
  • Measure fairness with several simultaneous downloads

The tasks

  1. How PCQ works
  2. Build the subscriber PCQ types and queue
  3. Measure fair sharing
  4. Measure the cap

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 PCQ - fair sharing and per-subscriber caps with one queue5 nodes and 1 network, 5 links. Every link is listed as text below the diagram.NETAPSUB1SUB2SUB3Subscribersether1ether2ether1ether1ether1ether1
5 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 AP ether1
  • AP ether2 to Subscribers (network)
  • SUB1 ether1 to Subscribers (network)
  • SUB2 ether1 to Subscribers (network)
  • SUB3 ether1 to Subscribers (network)
Nodes in PCQ: fair sharing and per-subscriber caps with one queue, 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
APMikroTik RouterOSmikrotik-7.14.21 vCPU, 256 MB
SUB1MikroTik RouterOSmikrotik-7.14.21 vCPU, 256 MB
SUB2MikroTik RouterOSmikrotik-7.14.21 vCPU, 256 MB
SUB3MikroTik 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 04 - PCQ - fair sharing and per-subscriber caps with one queue 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.