Description
Introduction to Practical Networking
Introduction to Practical Networking
Chris Carthern1 , William Wilson1, Richard Bedwell1 and Noel Rivera1
Chapter 1 begins by discussing a few of the tools that you will use throughout the book. Next, we cover the beloved OSI model and discuss how it relates to networking. We talk about all seven layers of the OSI model. Then we move on to the TCP/IP model and show its relation to the OSI model. We end the chapter discussing well-known port numbers, the different types of networks, and Cisco’s hierarchical internetwork model.
So you want to become a good network engineer? Let us give you some advice: do not believe that you know everything there is to know about networking. No matter what certifications or years of experience you have, there will always be gaps in knowledge, and people that know or have experienced issues that you may not have. Troubleshoot issues systematically from layer to layer. Use your resources—such as this book! You can never have too many resources at your disposal in your toolbox. Do not be afraid to ask for help. Do not be ashamed because you cannot resolve a problem. That is why we have teams of engineers. Everyone has their expertise and we must use each to our advantage. Remember when dealing with networks it is always better to have a second pair of eyes and another brain to help resolve issues quickly. This will help you save time and stop you from working in circles. You want to know how you can become a good network engineer? Start by reading this book and complete the lab exercises to reinforce what you have learned. The rest will come from experience on the job. Practice makes perfect!
Tools of the Trade
How do you practice in a lab setting? We all cannot go around buying our own network equipment and creating our own lab environment. The best thing is to configure and test with real equipment that can be bought secondhand on eBay. There are also many tools that can be used to simulate routers in a virtual environment. Because all of the devices are virtual, they come with limitations on what you can do with them. These limitations are discussed in Appendix A.
To become proficient at anything, practice is needed, and to be efficient, tools are needed. Our tool of choice to practice and simulate network topologies is the Graphical Network Simulator (GNS3), and our tool of choice to peek into the network packets is Wireshark. There are other tools that you can use, but we found these two to be the easiest and most straightforward. Just in case you want to look at other options, a quick Internet search for “network simulators” and “network sniffers” will provide a list of the available alternatives to GNS3 and Wireshark, respectively.
GNS3 provides a simple all-in-one distribution that integrates Wireshark, VirtualBox, Qemu, and Dynamips among other tools, allowing simulation of network devices and virtualized workstations or servers. A simple visit to www.gns3.com and https://www.wireshark.org , or a search on YouTube will glean vast amounts of information on how to use the tools. You need to be able to get an IOS image; do not violate any license agreements. We will use GNS3 and Wireshark exclusively throughout this book.
Cisco Packet Tracer is a network simulation tool that allows you to simulate the configuring, operation, and troubleshooting of network devices. For more information, visit https://www.netacad.com/web/about-us/cisco-packet-tracer .
Cisco Virtual Internet Routing Lab (VIRL) is a network simulation tool that uses virtual machines running the same IOS as Cisco’s routers and switches. It allows you to configure and test real-world networks using IOS, IOS XE, IOS XR, and NX-OS. For more information, visit http://virl.cisco.com .