What is Internet Exchange Point?
Also known as: IXP, IX
A physical infrastructure facility where multiple autonomous networks interconnect to exchange traffic directly, bypassing transit ISPs to reduce latency and cost.
An Internet Exchange Point (IXP) is a physical location where networks connect to each other to exchange traffic directly, without paying a third-party transit provider. Each participating network extends a router to the IXP facility and connects to a common Layer 2 switching fabric. On that shared Ethernet network, the networks establish BGP peering sessions with each other or use route servers to automate the exchange of routes.
Traffic between two networks connected to the same IXP flows through the IXP switch fabric instead of traversing the public Internet. This direct path reduces latency, improves throughput, and lowers the cost of delivering traffic that would otherwise travel through multiple upstream providers. The IXP itself is neutral: it provides the physical space, power, cooling, and the switching infrastructure but does not route traffic or inject its own routes into BGP.
IXPs are usually located inside carrier-neutral colocation datacenters. The most common protocol for the switching fabric is Ethernet, often at 10, 40, or 100 Gbps speeds per port, with 400 Gbps becoming more common. The control plane uses BGP, with peering LANs typically using IPv4 and IPv6 on the same VLAN. Many IXPs also provide route servers that collect routes from members and redistribute them, reducing the number of BGP sessions from O(N*N) to O(N). Prominent IXPs include AMS-IX, DE-CIX, LINX, and Equinix Internet Exchange. IXPs are critical for keeping local traffic local, especially for content delivery networks and cloud providers.
Key facts
- IXPs operate Layer 2 switching fabrics, not routing; all routing is done by the member networks using BGP.
- The peering agreement between networks at an IXP is either private bilateral or open multilateral via a route server.
- Most IXPs require a minimum port speed (commonly 1 Gbps or 10 Gbps) and enforce a peering policy to prevent abuse.
- Traffic exchanged at an IXP is settlement-free (peering) unless the IXP itself charges membership or port fees.
- The largest IXPs handle multiple Tbps of throughput, with AMS-IX peak traffic often exceeding 10 Tbps.
How it works in practice
Related terms
References
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