Trying to find the perfect networking resource or textbook can be a real challenge.
Sometimes they are extremely focused on one technology, and thus miss the mark. Or
they are extremely broad, covering every networking idea known to man. This book is
about something that all networks have in common—the core protocols. Networks
have a couple of basic building blocks: routers, switches, access points, and hosts.
These building blocks use a particular set of rules when forwarding bits of information
from one side of the network to another.
These bits are wrapped up in a neat little package called a packet. Packets have many
qualities, but one thing they never do is lie. If a packet is present, it is there because
some device or network host put it there. By looking at the packets running on a
network and understanding the forces (sometimes good, sometimes evil) that put them
there, we can gain a deep understanding of how networks operate and what is happening
at a given moment.
This book provides the structure (a.k.a. model) used to formulate network transmissions
and then dives into the major protocols populating almost every single network
today: Ethernet, Internet Protocol (IP), Address Resolution Protocol (ARP), and the
Internet Control Message Protocol (ICMP). But this is not simply a description of the
foundation protocols. In each chapter, the protocol is analyzed by examining topologies
and the packets generated on actual networks. Wireshark is the tool of choice. It
is not only powerful but the folks out at wireshark.org continue to provide it free of
Almost all network devices and hosts use tables to make decisions. The packets are on
the network because a table was consulted and the result indicated that a transmission
be sent. So the packets are the end result. Inside these pages you will find discussion
and examples of the ARP tables, routing tables, and source address tables. Tying it all
together will be step-by-step descriptions of the processes used so that the reader will
be able to completely trace and understand the content of the packets and the events
within the communications architecture.