Computers

TCPIP

Until recently, computer systems were isolated workstations that communicated with each other only with difficulty. Either it was a stand-alone unit, or if it was bought to be part of a system, you had to buy a network communication system to go with it. In the 1970’s and 1980’s, more sophisticated networks began to become more common. Dozens of architectures populated the networks of this time, with companies such as IBM, Digital, Sperry, Burroughs, and Honeywell being largely involved in this development. Problems arose when these proprietary networks needed to communicate to another workstation outside of their network. Later in the 1980’s, LANs became more commonly used to connect workstations, but they tended to utilize proprietary rules of communication called protocols. Protocols such as Novell’s IPX/SPX, AppleTalk, and IBM and Microsoft’s NetBEUI were better for communication, but they still presented problems. Getting a PC to talk to a mainframe required specialized technologies that would turn a “smart” PC into a dumb terminal that could be permitted within the mainframe’s sphere of influence. Near the end of the 1980’s, network isolation became unacceptable. Businesses realized that LANs served vital business needs, they were important databases and sharing the stored information was critical.

TCP/IP, the network protocol, was invented by the Department of Defense due to its complex network requirements. TCP/IP provided a common protocol suite that could be specified for all networks, would operate with equipment from various vendors, was easy to configure, high performing, and reliable.

TCP/IP is a protocol suite, or group of protocols, which allows communication over the Internet of in private networks ranging from home offices to enterprise networks. TCP/IP is constructed to cover the seven layers of the OSI model. The application, presentation and session layers are made up of the Telnet, FTP, TFTP, SMPT, LPD, NFS, SNMP, X Window, SQL, RPC, DNA, and SCP protocols. The transport layer is composed of the TCP and UDP protocols. The protocols included in the network layer are IP, ICMP, ARP, RARP, and BootP. The data link layer is made of LAN protocols, Ethernet: 100 BaseFx, 100 Base4, 100BaseTX, Token Ring FDDI and WAN protocols ISDN, PPP, SLIP, X.25, LAPB, Frame Relay, HDLC, SDLC, and other protocols. Finally, the physical layer is made of EIA/TAI-232, EIA/TIA-449, V.24, V.35, X.21, G.703, EIA-530, HSSI, and others.