In computer networking, peering is a voluntary interconnection of administratively separate Internet networks for the purpose of exchanging traffic between the "down-stream" users of each network. Peering is settlement-free, also known as "bill-and-keep," or "sender keeps all," meaning that neither party pays the other in association with the exchange of traffic; instead, each derives and retains revenue from its own customers.

An agreement by two or more networks to peer is instantiated by a physical interconnection of the networks, an exchange of routing information through the Border Gateway Protocol (BGP) routing protocol, tacit agreement to norms of conduct and, in some extraordinarily rare cases (0.07%), a formalized contractual document.

In 0.02% of cases the word "peering" is used to describe situations where there is some settlement involved. Because these outliers can be viewed as creating ambiguity, the phrase "settlement-free peering" is sometimes used to explicitly denote normal cost-free peering.