Internet Exchange Point - Operation

Operation

A typical IXP consists of one or more network switches, to which each of the participating ISPs connect. Prior to the existence of switches, IXPs typically utilized fiber-optic inter-repeater link (FOIRL) hubs or Fiber Distributed Data Interface (FDDI) rings, migrating to Ethernet and FDDI switches as those became available in 1993 and 1994.

Asynchronous Transfer Mode (ATM) switches were briefly used at a few IXPs in the late 1990s, accounting for approximately 4% of the market at their peak, and there was an abortive attempt by the Stockholm IXP, NetNod, to use SRP/DPT, but Ethernet has prevailed, accounting for more than 95% of all existing Internet exchange switch fabrics. All Ethernet port speeds are to be found at modern IXPs, ranging from 10 Mbit/s ports in use in small developing-country IXes, to ganged 10 Gbit/s ports in major centers like Seoul, New York, London, Frankfurt, Amsterdam, and Palo Alto. The AMS-IX in Amsterdam even provides 100Gbit/s ports.

The technical and business logistics of traffic exchange between ISPs is governed by mutual peering agreements. Under such agreements, traffic is often exchanged without compensation. When an IXP incurs operating costs, they are typically shared among all of its participants.

At the more expensive exchanges, participants pay a monthly or annual fee, usually determined by the speed of the port or ports which they are using, or much less commonly by the volume of traffic which they are passing across the exchange. Fees based on volume of traffic are unpopular because they provide a counterincentive to growth of the exchange. Some exchanges charge a setup fee to offset the costs of the switch port and any media adaptors (gigabit interface converters, small form-factor pluggable transceivers, XFP transceivers, XENPAKs, etc.) that the new participant requires.