Internet Exchange Points
How an Internet Exchange Point Connects Networks
An internet exchange point (IXP) is a physical location where multiple networks connect to a shared switching system so they can exchange traffic directly. Instead of buying a separate link to each network, a participant connects to the exchange once and can reach every other network that is also present there.
An IXP is usually housed in a data center or carrier neutral facility. Each network places a router in the building and links it to the exchange's switches, normally with a short fiber run or a cross connect. The exchange itself does not carry traffic to the wider internet. It is the meeting point where networks decide to exchange traffic with each other.
Why Hosting Providers Connect to an IXP
Traffic that stays within a region is often faster and cheaper to deliver through a local exchange. If a hosting provider and a visitor's internet provider both connect to the same IXP, traffic between them can travel a short, direct path instead of crossing several transit networks.
This can lower latency, which is the delay before data arrives, and reduce transit costs, because less traffic has to be paid for by the megabit. The benefit depends on who else is connected. An exchange with many local consumer networks, content providers and hosts is more useful than one with few participants. Location effects on speed are discussed in server location and latency.
Hosts also use exchanges to find and set up peering relationships. A single port often gives access to many networks, and each of them may agree to exchange routes. The commercial trade-offs of peering are compared in IP transit vs peering.
Route Servers and Peering Policies at an IXP
Setting up a separate peering session with every network at an exchange would be a lot of work. Many exchanges therefore run a route server. A route server is a special router that collects the routes each participant offers and passes them on to the others, so a participant can learn routes from many networks through one session. The route server shares routing information but does not sit in the path of the traffic itself.
Route servers are optional. Participants that want more control can set up direct sessions with specific networks and configure their routing policy for each neighbor. Some networks have open peering policies that accept most requests, while others are selective and peer only with networks that meet certain traffic levels or technical criteria.
Frequently asked questions
Does joining an internet exchange point make a website faster?
It can, but only for visitors whose internet providers also connect to the same exchange. An IXP shortens the path for traffic between its participants. Traffic to networks outside the exchange still follows normal transit routes. Website speed also depends on server performance, application code and other network factors, so an exchange is only one part of the picture.
Do I need to be a network operator to use an IXP?
Generally, yes. Joining an exchange usually requires an autonomous system number, equipment that speaks BGP and a port at the exchange. Most website owners and small businesses do not join directly. Their hosting or colocation provider may connect to an IXP instead, which lets its customers benefit from the shorter paths.