The internet is a fundamental communication technology for today's modern society. The thing that started as the \Gls{arpanet}\cite{wiki:ARPANET} back in the late nineteen sixties has evolved to become the core of today's globalization on Earth.
\item\textbf{Tier 1:} The granddaddies which does not pay for \Gls{ip} transit traffic from any other providers. They typically operate on the grand scale of the world and will often maintain peerings with most other tier 1 providers.
\item\textbf{Tier 2:} Pays for \Gls{ip} transit traffic from the tier 1 providers and will maintain a select number of peerings between each other to reach certain prefixes by a shorter path. The granddaddies are paid to be able to reach the parts of the internet the tier 2 providers cannot reach through peerings with other tier 2 providers and \Glspl{cdn}.
\item\textbf{Tier 3:} These networks can be large fx. large corporations, smaller local providers who do \textit{not} have downstream \Gls{ip} transit customers of their own and no peering relation ships.\footnote{Conditions comparable to \Gls{ospf} stub networks}