Peering says two networks create a connection, but doesn`t specify how they`re connected. The process can be initiated by running a circuit from one institution to another, but this method becomes ineffective if a network requires multiple peers. Two other more frequent and effective types of peering are called public and private peers. Much of the complexity of the BGP routing protocol is available to support the application and adjustment of peering and transit agreements. BGP allows operators to define a policy that determines where traffic is routed. Three things commonly used to determine routing are local presets, multi-exit discriminators (MEDs) and AS-Path. Local preferences are used internally in a network to distinguish network classes. For example, for a given network, a higher preference is given for internal and customer ads. Non-billing peering is then configured to be preferred to paid IP transit.
The “Donut Peering” model  describes the intensive networking of small and medium-sized regional networks, which make up a large part of the internet.  Traffic between these regional networks can be modeled as a toroid, with a nuclear donut hole poorly connected to the networks around them.  Network managers may be motivated for peeric reasons for a wide range of business and technical reasons. The motivations of peering networks can be: by definition, peering is the voluntary and free exchange of movement between two networks for mutual benefit. If one or both networks believe that there are no more reciprocal benefits, they may decide to stop peering: this is called depeering. One of the reasons one network wants to evaluate another is that public peers are more frequent and effective through an internet exchange. An internet exchange is an Ethernet switch (or set of Ethernet switches) in a colocation device with which all networks of the device connect. The exchange of the internet allows a network to connect by a single connection to many other networks.
Peering agreements have yet to be negotiated with each peer, but no new wiring is required. Netnod operates route servers on its internet exchanges in Stockholm and Copenhagen.