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by Steve Burnett
The suite of widely used protocols known as Transmission Control Protocol/Internet Protocol (TCP/IP) has become extremely important as networks of all sizes, including the Internet, depend on it for their communications.
TCP/IP has grown from its initial development as a government-sponsored project to widespread use, connecting networks of all sizes. Recognized for its capability to enable communication among dissimilar machines, it’s found on virtually all workstations, minicomputers, and mainframes. This chapter describes the origins and language of TCP/IP, its addressing and naming conventions, and concepts fundamental to the creation of the Internet.
In the late 1960s, the U.S. Department of Defense (DOD) recognized an electronic communication problem developing within the department. Communicating the ever-increasing volume of electronic information among DOD staff, research labs, universities, and contractors had hit a major obstacle. The various entities had computer systems from different computer manufacturers, running different operating systems, and using different networking topologies and protocols. How could information be shared?
The Advanced Research Projects Agency (ARPA) was assigned to resolve the problem of dealing with different networking equipment and topologies. ARPA formed an alliance with universities and computer manufacturers to develop communication standards. This alliance specified and built a four-node network that’s the foundation of today’s Internet. During the 1970s, this network migrated to a new, core protocol design that became the basis for TCP/IP.
The mention of TCP/IP requires a brief introduction to the Internet, a huge network of networks that allows computers all over the world to communicate. It’s growing at such a phenomenal rate that any estimate of the number of computers and users on the Internet would be out of date by the time this book went to print! Nodes include universities, major corporations, research labs in the United States and abroad, schools, businesses both large and small, and individually owned computers. The explosion in past years of the World Wide Web has driven the Internet’s expansion. In addition, the Internet is also a repository for millions of shareware programs, news on any topic, public forums and information exchanges, and e-mail. Another feature is remote login to any computer system on the network by using the Telnet protocol. Because of the number of systems that are interconnected, massive computer resources can be shared, enabling large programs to be executed on remote systems. Massively distributed processing projects such as the 1997 decryption of the Data Encryption Standard are possible only with the “everything is connected to everything else” behavior of the Internet.
The Internet protocol suite is composed of many related protocols based on the foundation formed by TCP and IP. To clarify the relationship of these components, Table 23.1 provides some definitions and notations.
| Term | Definition |
|---|---|
| datagram | Used interchangeably with the words data packet and network message to identify a unit of information that’s exchanged. |
| DNS | Domain Name Service, a service provided by one or more computers in a network to help locate a path to a desired node. This saves every system on a network from having to keep a list of every system it wants to talk to. Used by mail gateways. |
| GOSIP | Government Open System Interconnection Profile, a collection of OSI protocols used in U.S. government computer networks and projects. |
| Internet | A computer network based on TCP/IP and related protocols. A public network of networks interconnecting businesses, universities, government facilities, and research centers. |
| FTAM | File Transfer, Access, and Management, a file transfer and management protocol as specified by OSI. |
| FTP | File Transfer Protocol, which enables file transfer between systems. |
| IP | Internet Protocol, a protocol responsible for transporting datagrams across the Internet. |
| NFS | Network File System, a network virtual disk system that enables a client computer to mount remote file systems and directories. Originally developed by Sun Microsystems. |
| NIC | Network Information Center, responsible for administering Internet and TCP/IP addresses, as well as network names. |
| node | A computer on a network. |
| OSI | Open System Interconnection, the ISO standard model for defining data communication. |
| RFC | Request For Comments, the documentation maintained by NIC relating to Internet protocols, addressing, routing, configuration, and other related Internet topics. |
| RIP | Routing Information Protocol, which is used to exchange information between routers. |
| RMON | Remote monitor, a remote network monitor that enables the collection of information about network traffic. |
| RPC | Remote Procedure Call, which enables procedures to be executed on a server. |
| SMTP | Simple Mail Transfer Protocol, which is used to transfer electronic mail between systems. |
| SNMP | Simple Network Management Protocol, a protocol used to manage remote network devices and to collect information from remote devices related to configuration, errors, and alarms. |
| TCP | Transmission Control Protocol, the protocol between a pair of applications responsible for reliable, connection-oriented data transmission. |
| Telnet | The protocol used to establish remote terminal connections. |
| UDP | User Datagram Protocol, a connectionless protocol used to transfer data between agents. |
| VT | Virtual terminal, a method for using Telnet to log in to remote systems through the network. |
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