The internet is not a cloud: it is a collection of tens of thousands of separate networks — autonomous systems (ASes) — that tell each other about their routes over BGP. IP transit is the service through which your network reaches the rest of the internet via one of those other networks.
How it works
A transit provider runs a network that can reach the entire internet, directly or indirectly: through its own connections to other networks (peering) and through its own upstreams. When you buy transit, you:
- set up a BGP session with the provider's router;
- announce your own IP prefixes, so the rest of the world knows your addresses are reachable through that provider;
- receive the full table: over a million routes from which your router picks the best one per destination.
From that moment your network is a full participant in the internet, under your own AS number.
Transit versus peering
At internet exchanges such as NL-IX or AMS-IX, networks exchange traffic among themselves: peering. That is usually free, but you only reach the networks that are present there and willing to peer with you. Transit fills that gap: a single provider that, for a fee, carries your traffic everywhere else. In practice, networks combine the two: peering for the traffic that is close by, transit for the rest.
Why use multiple transit providers (multihoming)?
With a single transit provider, your reachability depends on a single provider. Multihoming — sessions with two or more providers, or with the same provider in multiple locations — gives you redundancy: if one drops out, BGP automatically takes the other route. With BGP communities you also steer which traffic goes which way.
What to look for in a transit provider
- Routes and latency — direct paths to the networks your traffic is headed for;
- Capacity — whether the connection can scale with your traffic;
- Features — BFD for fast failover, large communities for traffic engineering, proper route filtering (IRR);
- People — do you get an engineer on the line, or a ticket queue?
IP transit at Xyphen IT
We provide IP transit on our own network (AS211588): dual-stack IPv4 + IPv6, BFD, RFC 8092 large communities and multihoming across multiple PoPs. Prefer the details? Read the technical version with configuration examples. No AS number or IP space of your own yet? As a RIPE member we can help with LIR services such as AS sponsorship.