Point-to-Point Addressing

What this chapter covers

Point-to-Point Addressing is about numbering a link between two routers without wasting a subnet on it.

The chapter has one syllabus topic, and it is short but easy to get wrong. It shows how RouterOS uses the network parameter of an address to store the peer, and what that does to the connected route.

You will meet the same idea again in PPP tunnels and in OSPF point to point networks, so it is worth learning well here.

How the topics fit together

The single topic connects the static routing chapter before it with the tunnel and OSPF chapters after it.

The pattern is always the same:

• Give each router one address on the link.
• Tell each router the peer address in network.
• Let RouterOS create a connected route to the peer.
• Add routes or a protocol for everything behind the peer.

The static routing pages explain how a gateway is chosen. A point to point peer is a very common gateway, and the connected host route is what makes it reachable.

Think of the link as a pair of host addresses instead of a small network. Each router only needs to know its own address and the address of the router at the other end. Nothing else lives on the link, so there is no network address or broadcast address to waste.

How to use these pages

The topic page has the same shape as every other page in this guide, 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.

Set up two routers with a cable between them. Configure the pair of addresses, print the address and route tables on both, and ping the peer. Then compare what you see with a normal /30 configuration on the same link.