CloudLabBox
Try the free demo

MikroTik MTCINE lab 7 of 12

LDP VPLS full mesh - split horizon and control word and L2MTU

A colleague started a three-site VPLS for Harper Ltd and left it half working. Troubleshoot the pseudowires, fix a missing split horizon that floods duplicate frames, enable the control word, and work out the L2MTU the core needs, including how RouterOS fragments VPLS traffic that doesn't fit.

Run this lab

It needs Lite: its 6 nodes are set to 6 vCPU and 1,536 MB in total. That fits the free demo too.

In your workspace: Shared, then MikroTik MTCINE RouterOS v7 guided labs, then 07 - LDP VPLS full mesh - split horizon and control word and L2MTU

Try it free for 30 minutesRun it on Lite from £3 a day

The free demo needs no card and no email. Every lab plan includes every guided lab.

Level
Advanced
Time
About 90 minutes
Nodes need
6 vCPU, 1,536 MB
Smallest plan
Lite

The scenario

Harper Ltd now has three sites, and wants them on one Ethernet segment, 10.50.0.0/24. A colleague started a VPLS across Fernvale's three PE routers before going on leave, with a note: "Mostly done. Site 3 doesn't work yet. Also check the MTU, Harper's servers send 1500-byte packets." The core (OSPF and LDP) is fine. Find what is wrong with the VPLS, fix it, then finish the job properly.

RouterLoopbackCore linksCustomer port
PE110.255.255.1ether1 10.0.12.1/30 (PE2) · ether2 10.0.13.1/30 (PE3)ether3: CE1 10.50.0.1
PE210.255.255.2ether1 10.0.12.2/30 (PE1) · ether2 10.0.23.1/30 (PE3)ether3: CE2 10.50.0.2
PE310.255.255.3ether1 10.0.13.2/30 (PE1) · ether2 10.0.23.2/30 (PE2)ether3: CE3 10.50.0.3

What you’ll practise

  • Build and read a full mesh of LDP-signalled VPLS pseudowires
  • Troubleshoot pseudowires with /interface vpls print and monitor: VPLS ID and peer mismatches
  • Explain bridge split horizon and why every pseudowire port in a full mesh needs it
  • Explain what the VPLS control word does, including fragmentation on RouterOS
  • Calculate the L2MTU a VPLS core needs and test it with do-not-fragment pings

The tasks

  1. Map the service
  2. Fix the pseudowires
  3. Split horizon
  4. Turn on the control word
  5. Work out the L2MTU

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 LDP VPLS full mesh - split horizon and control word and L2MTU6 nodes, 6 links. Every link is listed as text below the diagram.PE1PE2PE3CE1CE2CE3ether3ether1ether3ether1ether3ether1ether1ether1ether2ether1ether2ether2
6 nodes, with the interface names each link uses. On a narrow screen, scroll the diagram sideways.
Every link, as text
  • PE1 ether1 to PE2 ether1
  • PE1 ether2 to PE3 ether1
  • PE2 ether2 to PE3 ether2
  • PE1 ether3 to CE1 ether1
  • PE2 ether3 to CE2 ether1
  • PE3 ether3 to CE3 ether1
Nodes in LDP VPLS full mesh - split horizon and control word and L2MTU, with the image each runs and the vCPU and RAM it’s set to
NodeDeviceImage in Add NodeSet to
PE1MikroTik RouterOSmikrotik-7.14.21 vCPU, 256 MB
PE2MikroTik RouterOSmikrotik-7.14.21 vCPU, 256 MB
PE3MikroTik RouterOSmikrotik-7.14.21 vCPU, 256 MB
CE1MikroTik RouterOSmikrotik-7.14.21 vCPU, 256 MB
CE2MikroTik RouterOSmikrotik-7.14.21 vCPU, 256 MB
CE3MikroTik 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 MTCINE RouterOS v7 guided labs.

  3. Open 07 - LDP VPLS full mesh - split horizon and control word and L2MTU 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 MikroTik MTCINE labs

All MikroTik MTCINE labs

Related labs in other courses

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.