Systems Used for Testing

Every example in the book was run on an actual network and the resulting output saved in a file for inclusion in the text. Figure 1.11 shows a diagram of the different hosts , routers, and networks that are used. (This figure is also duplicated on the inside front cover for easy reference while reading the book.) This collection of networks is simple enough that the topology doesn't confuse the examples, and with four systems acting as routers, we can see the error messages generated by routers.

Most of the systems have a name that indicates the type of software being used: bsdi, svr4, sun, Solaris, aix, slip, and so on. In this way we can identify the type of software that we're dealing with by looking at the system name in the printed output.

A wide range of different operating systems and TCP/IP implementations are used:

BSD/386 Version 1.0 from Berkeley Software Design, Inc., on the hosts named bsdi and slip. This system is derived from the BSD Networking Software, Release 2.0. (We show the lineage of the various BSD releases in Figure 1.10.)
Unix System V/386 Release 4.0 Version 2.0 from U.H. Corporation, on the host named svr4. This is vanilla SVR4 and contains the standard implementation of TCP/IP from Lachman Associates used with most versions of SVR4.
SunOS 4.1.3 from Sun Microsystems, on the host named sun. The SunOS 4.1.x systems are probably the most widely used TCP/IP implementations. The TCP/IP code is derived from 4.2BSD and 4.3BSD.
Solaris 2.2 from Sun Microsystems, on the host named Solaris. The Solaris 2.x systems have a different implementation of TCP/IP from the earlier SunOS 4.1.x systems, and from SVR4. (This operating system is really SunOS 5.2, but is commonly called Solaris 2.2.)
AIX 3.2.2 from IBM on the host named aix. The TCP/IP implementation is based on the 4.3BSD Reno release.
4.4BSD from the Computer Systems Research Group at the University of California at Berkeley, on the host vangogh.cs.berkeley.edu. This system has the latest release of TCP/IP from Berkeley. (This system isn't shown in the figure on the inside front cover, but is reachable across the Internet.)

Although these are all Unix systems, TCP/IP is operating system independent, and is available on almost every popular non-Unix system. Most of this text also applies to these non-Unix implementations, although some programs (such as Traceroute) may not be provided on all systems.