IP Transit vs Peering
What IP Transit and Peering Are
IP transit vs peering describes two ways networks exchange traffic. IP transit is a paid service in which one network, the transit provider, carries a customer's traffic to and from the rest of the internet. Peering is an arrangement in which two networks exchange traffic directly, usually for the traffic that flows between their own customers. Transit gives reach to everything. Peering gives a shorter, direct path to specific networks.
The internet is made of tens of thousands of independent networks, called autonomous systems. Each one announces the IP address ranges it controls to its neighbors using the Border Gateway Protocol (BGP), the routing protocol that tells routers which path leads to each destination. A network that wants to reach every other network needs routes to all of them. Transit provides that. Peering provides direct routes to a chosen set of networks.
How IP Transit Is Priced and Used
Transit is usually billed by the amount of bandwidth used. A common method is the 95th percentile: the provider samples traffic at regular intervals over a month, discards the top five percent of samples and bills the highest remaining value. This smooths out short bursts. Other providers bill on a committed rate or a flat port fee.
Transit suits a network that must reach the whole internet, including networks it has no direct arrangement with. A hosting company serving visitors worldwide typically relies on transit as its base, because no single network connects directly to everyone. Many networks buy transit from more than one provider, a setup called multihoming.
The main trade-off is cost. Every megabit sent through a transit provider is paid for, so heavy traffic can become expensive. Transit also leaves the path to many destinations largely in the provider's hands.
How Peering Works and Its Two Forms
Peering takes two main forms. Settlement-free peering means neither network pays the other. Each side agrees to carry the other's traffic toward its own customers, usually when the volume exchanged is roughly balanced. Paid peering means one side pays a fee, often because it sends far more traffic or gets more value from the link.
Peering can happen in two places. Public peering takes place at an internet exchange point, where many networks connect to a shared switching system. Private peering uses a direct link between two networks, often a physical cross connect inside a data center, and suits large traffic volumes between two parties.
Example: A Hosting Network Mixing Transit and Peering
Imagine a hosting company whose visitors are mostly on a few large consumer networks in the same region. The company peers with those networks at a local exchange, so traffic to them travels a short path without transit fees on that traffic. It keeps a transit contract for everything else, such as visitors on networks it does not peer with. Its routing policy prefers the peering routes when they are available and falls back to transit otherwise.
Frequently asked questions
Is peering always cheaper than IP transit?
Not always. Settlement-free peering avoids per-megabit charges for the traffic it carries, but it still needs equipment, a port at the exchange or a cross connect, and staff time. Paid peering and large private links can also be costly. Transit is simpler to start with, because one contract reaches the whole internet. The cheaper option depends on traffic volume, location and the networks involved.
Can a small website owner buy IP transit or peering directly?
Usually not. These services are sold to networks that run their own autonomous system number and routing equipment. Website owners normally get connectivity through a hosting provider or colocation operator, which buys transit and peering on their behalf. The provider's network choices then shape the speed and reach of the website.