abstraction

application architecture

architecture

client$$server $($model$)$

cloud computing

decomposition

environment

infrastructure as a service

$($IaaS$)$

interface

intranet

middleware

n$-$tier architecture

peer$-$to$-$peer architecture

platform as a service $($PaaS$)$

shared server

software as a service $($SaaS$)$

subsystem

system

three$-$tier architecture

top$-$down approach

two$-$tier architecture