Abstract: A Computer network is an association of network devices to data communication. Various networks are associated together to shape an internet work. OSI is an open access system interconnection reference model, is a generally excellent arrangement characterized protocol determinations. OSI model has seven layers; each layer can have a few sub-layers. Network reference models were created to address these difficulties. Two helpful reference models are Open System Interconnection (OSI). Transmission Control Protocol and Internet Protocol (TCP/IP) fill in as protocol design subtleties the communication between applications on network devices.