Figure 1.11 shows the test network that is used for all the examples in the text. This figure is also duplicated on the inside front cover for easy reference while reading the book.
Most of the examples are run on the lower four systems in this figure (the author's subnet). All the IP addresses in this figure belong to the class B network ID 140.252. All the hostnames belong to the .tuc.noao.edu domain. ( noao stands for "National Optical Astronomy Observatories" and tuc stands for Tucson.) For example, the lower right system has a complete hostname of svr4.tuc.noao.edu and an IP address of 140.252.13.34. The notation at the top of each box is the operating system running on that system. This collection of systems and networks provides hosts and routers running a variety of TCP/IP implementations .
It should be noted that there are many more networks and hosts in the noao.edu domain than we show in Figure 1.11. All we show here are the systems that we'll encounter throughout the text.
In Section 3.4 we describe the form of subnetting used on this network, and in Section 4.6 we'll provide more details on the dialup SLIP connection between sun and netb. Section 2.4 describes SLIP in detail.