Networking has become a fundamental feature of most computer applications. (TCP/IP), the protocol suite used by the Defense Advanced Research Projects Agency (DARPA) Internet, is one of the most commonly used network protocols. The DARPA Internet is a collection of networks and gateways that function as a single network. The Internet extends all over the globe and consists of over 100,000 computers.
Finding a way to connect existing computer networks of diverse types was a primary goal in the design of TCP/IP. Achieving of this goal has made TCP/IP particularly successful in the networking of computers that run different operating systems and that are manufactured by different vendors. TCP/IP is also designed to accommodate a very large number of host computers and local networks. A site or organization that uses TCP/IP need not be connected to the Internet, but most sites and organizations are connected.
The open, nonproprietary nature of TCP/IP and its global scope have made it popular among users of the UNIX operating system. Standards for writing communications programs in C have also become widespread. The two most common standards are the BSD UNIX Socket Library interface and the UNIX System V Transport Layer Interface (TLI).
The SAS/C Library currently implements the BSD UNIX Socket Library interface because it is somewhat more common than TLI, and it has better support from the underlying communications software on OS/390 and CMS systems. The socket library is integrated with SAS/C support for UNIX file I/O to provide the same type of integration between file and network I/O that is available on BSD UNIX systems.
TCP/IP is now a base for higher level protocols that support many popular networking applications. Some of these protocols are:
The multivendor capabilities of these protocols and the applications that use them have made them particularly successful.
Copyright © 2001 by SAS Institute Inc., Cary, NC, USA. All rights reserved.
