Companies that own and operate these networks – service providers, businesses, universities, governments – agree on what happens when your email is moved from one network to another. Peering is that they agree to freely exchange their transport for mutual interest. Some of them are related to the economy. How much traffic do you have? How much do you pay for transit? How much of this traffic could be easily moved to peering? How much will peering cost, including connectivity and people to manage it? Will you save money? These costs are easy to put in a calculation board and see how they stack up for you. Private peering is peering between parties that bypass part of the basic public network, which handles most of the Internet traffic. In a regional territory, some ISPs exchange local peering agreements, instead of or in addition to peering with a BACKBONE-ISP. In some cases, peer transportation costs include transit costs or the effective access fee for the larger network. Properly spoken, peering is simply the agreement to link and exchange routing information between them. Peering is, by definition, the voluntary and free exchange of movement between two networks in the mutual interest. If one or both networks believe that there are no more reciprocal benefits, they may decide to stop peering: this is called depeering. Reasons for a network`s interest include: a two- or more-network agreement with peers is established by physical networking, routing information on the on-board gateway protocol (BGP) routing protocol and, in some specific cases, a formalized contract document.  Whether peering is the right one for you depends on several factors. Peering agreements can be considered non-residential or fee-paying.
Effective exchange of data traffic through peer-to-peer relationships can be either a private transaction between a small number of operators or through public agreements on an Internet Access Exchange (IX). That`s how it works. There are several types of connections together. Peering just means that two networks connect in one way or another. This could mean that a circuit through the city goes from the installation of one network to another. However, this regulation requires covering the costs of a subway link between peers. For many of their peers, it would be costly quickly. Peering requires the exchange and updating of router information between ISPs by peers, usually using the border gateway protocol (BGP). Peering parties network in network nodes such as network access points (NAP) in the United States and regional switching points.
Initially, there was no exchange of funds for peering agreements. More recently, however, some larger ISPs have charged smaller ISPs for peering. Each large ISP generally develops a peering policy that defines the conditions under which it alternates with other networks for different types of traffic. Today, some ISPs with similar data traffic may still decide to network through peering agreements. 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.  Public peering is done using layer 2 access technology, commonly referred to as “shared fabric.” On these sites, several network operators connect to one or more other network managers via a single physical port. In the past, public peering sites have been designated as network access points (NAPs).