Peering

Peering is the direct, typically settlement-free interconnection of two networks to exchange traffic between their respective customers, bypassing transit providers. Public peering happens over a shared switching fabric at an internet exchange, where one port can reach hundreds of other networks at once; private peering uses a dedicated cross-connect between two specific networks, usually inside a carrier-hotel or carrier-neutral data center, for large or latency-sensitive traffic flows. Networks document their peering relationships and policies in the PeeringDB database, which lists tens of thousands of facilities and exchange points globally and has become a de facto reference for judging a data center's connectivity density. Operators pursue peering to cut transit costs, reduce latency and hop count, and improve resilience by diversifying away from single upstream providers; facilities with rich peering ecosystems command a premium with content, cloud and gaming customers that need to reach eyeball networks directly.