Do you remember when we used multi-protocol routing for IPX, AppleTalk, andTCP/IP running on the same network? In the 1980s and early 1990s many enterprises had multiple protocols running on the physical network infrastructure as “ships in the night.” Cisco routers became highly adept at multi-protocol routing and the company grew in prominence as a result. Then in the early 1990s, TCP/IP won out and the internet took shape as the global network we enjoy today.
The TCP/IP protocol uses a very simple four-layer model (Application, Transport, Internet, and Link Layer). TCP/IP’s layers are much simpler to remember than the seven-layer Open Systems Interconnection model (OSI model) conceived in the 1980s.
