Chapter 2 of 3 · MikroTik MTCINE
MPLS
Labels, static mapping, LDP, PHP, traceroute, LDP and BGP based VPLS, MTU planning, VRFs and layer 3 VPNs.
- 7topics
- 33 minfast track
- 3diagrams and exhibits
Topics in this chapter
Take them in order, or jump to the one you need.
- 1MPLS Basics and Static Label MappingLearn how MPLS forwards packets by label, the roles of LER and LSR, the label header fields, and how static label bindings build…4 min
- 2LDP, Penultimate Hop Popping and MPLS TracerouteLearn how LDP distributes labels, why the penultimate router removes the label, and how MPLS changes traceroute output and the…Diagram5 min
- 3LDP Based VPLS, Bridge Split Horizon and the Control WordLearn how LDP based VPLS builds layer 2 tunnels between provider edge routers, why bridge horizon is needed in a full mesh, and…Diagram5 min
- 4L2MTU, MPLS MTU and FragmentationLearn why labels and tunnels need larger frames, how L2MTU and MPLS MTU differ, how to calculate VPLS overhead, and what happens…5 min
- 5BGP Based VPLSLearn how BGP based VPLS finds peers and signals pseudowires automatically using route distinguishers, route targets and site…4 min
- 6VRF and Route LeakingLearn how a VRF gives a router separate routing tables per customer, how route distinguishers and route targets work, and how to…5 min
- 7BGP Based Layer 3 VPNs and OSPF as the CE to PE ProtocolLearn how an MPLS layer 3 VPN carries customer routes in BGP between PE routers using VRFs and two labels, and how OSPF can run…Diagram5 min
About this chapter
What this chapter covers
This chapter explains how MPLS forwards by label and how providers use it to deliver layer 2 and layer 3 services.
It begins with the label mechanics, then moves to the services built on top. Examples use the RouterOS v6 console. The pages say where RouterOS v7 differs.
How the topics fit together
The chapter builds from the label, to the transport, to the services that run over it.
The order matters because each topic depends on the one before:
- MPLS basics and static mapping explain the label, the header and the tables.
- LDP, PHP and traceroute show how labels are distributed automatically, and what the core looks like to a trace.
- LDP based VPLS adds a layer 2 service, with split horizon and the control word.
- L2MTU and fragmentation show why every core link must be sized for the extra headers.
- BGP based VPLS replaces manual peers with automatic discovery.
- VRF and route leaking introduce separate routing tables.
- L3VPN and OSPF as the CE to PE protocol combine VRFs, BGP and labels into a routed VPN.
Almost every VPN fault comes back to two checks. Does the transport LSP exist, and does the frame size fit?
How to use these pages
Each topic page has the same shape, so you can skim for what you need.
- What it is: the idea in plain words.
- How it works: the mechanism, with diagrams and example commands.
- What to remember for the exam: the facts to memorise.
- Common mistakes: the classic traps.
- Check yourself: three questions to test your understanding.
A lab of four routers is enough to practise: two edge routers, one core router and a customer router at each end. Build the transport first and confirm the forwarding table. Only then add VPLS, VRFs and BGP, one service at a time.
Ready for more practice?
The full MikroTik MTCINE question bank has 475 questions, with timed practice exams and an explanation for every answer.
This study guide is independent and is not affiliated with, endorsed by, or sponsored by MikroTik. Vendor names, certification names and exam codes are trademarks of their respective owners and are used for identification only.