Peering
The term peering (English peer = equal ) refers to the association of peer computer networks for data exchange, eg between two Internet providers.
This data exchange is cost neutral basis ( without mutual payment claims ) between (mostly) the same major providers, regardless of the origin of the data packets. For this purpose, usually, a so -called " peering agreement" concluded that regulates the bilateral contract use.
However, it is quite possible that a large provider ( Tier 1 ) with a smaller provider ( Tier 2 ) to exchange data because it can either draw itself benefit or may require the smaller partner for his services money ( paid peering ).
A regular indirect transfer of data between different major providers on the other hand often billed according to the amount of data and called Transit.
Is the smallest plane on the peering used are free networks such as free radio, where the PicoPeeringAgreement is the foundation. Each individual node is, in itself constitutes a tiny providers, the connections between the nodes are peering between providers.
In a telephone network interconnection is called Interconnection ( to German: intermediate ).
Technology
The data exchange between providers is often done via peering points (PP ) (also known as Internet nodes ) can be connected to a plurality ( several hundreds ) of other participants. The number of peering agreements on an Internet node grows with the square of the number of connected nodes. For a table that represents all peering agreements, one therefore speaks of a peering matrix ( n * (n -1) possible entries). Routing information exchanged via the Border Gateway Protocol ( BGP).
The largest peering in Germany is DE- CIX in Frankfurt; smaller - partly regionally focused - peering points are for example ALP -IX in Munich, BCIX in Berlin, ECIX in Dusseldorf, Frankfurt, Berlin and Hamburg, N -IX in Nuremberg, S -IX in Stuttgart and the WORK- IX in Hamburg.
Route Server
To alleviate the quadratic growth of peering agreements, offer PPs Internet service providers also often the possibility to peer with a route server. The route server calculates for the connected router is representative of the best paths. It comes into being as a multilateral peering agreement. The peering matrix may nevertheless be influenced more often due to so-called communities.