Hartpence - Packet Guide to Core Network Protocols

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 commonthe 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 charge.

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.

Other key components of this book include addressing and equipment operation. Since lists of addresses are not much use to someone wishing to understand actual behavior, each chapter describes variation and application of these addresses. A chapter on masks has also been included because it is such an integrated part of every single network. Just for fun, there is a section on cabling to provide an explanation of why we connect things the way we do.

The sources used in this book are the actual standards as described by the IEEE and ITU-T. Wherever possible, RFCs are directly referenced. So, if you see it here, it came from either the original source or an operational network.

In a nutshell, this book will describe the core protocols, tables, and equipment used on contemporary networks. Each chapter will take topologies and packets from actual networks and explain why the packets were generated and the purpose of the content found in each. The goal is to provide an in-depth understanding of these components, security concerns, and operation.