CCNAv7-1: Introduction to Networks (ITN)

Welcome to Protocols and Models!

You know the basic components of a simple network, as well as initial configuration. But after you have configured and connected these components, how do you know they will work together? Protocols! Protocols are sets of agreed upon rules that have been created by standards organizations. But, because you cannot pick up a rule and look closely at it, how do you truly understand why there is such a rule and what it is supposed to do? Models! Models give you a way to visualize the rules and their place in your network. This module gives you an overview of network protocols and models. You are about to have a much deeper understanding of how networks actually work!

Welcome to Physical Layer!

The physical layer of the OSI model sits at the bottom of the stack. It is part of the Network Access layer of the TCP/IP model. Without the physical layer, you would not have a network. This module explains, in detail, the three ways to connect to the physical layer. Packet Tracer activities and labs will give you the confidence you need to cable up your own network! Let’s get busy!

Welcome to Number Systems!

Guess what? This is a 32-bit IPv4 address of a computer in a network: 11000000.10101000.00001010.00001010. It is shown in binary. This is the IPv4 address for the same computer in dotted decimal: 192.168.10.10. Which one would you rather work with? IPv6 addresses are 128 bits! To make these addresses more manageable, IPv6 uses a hexadecimal system of 0-9 and the letters A-F.

As a network administrator you must know how to convert binary addresses into dotted decimal and dotted decimal addresses into binary. You will also need to know how to convert dotted decimal into hexadecimal and vice versa. (Hint: You still need your binary conversion skills to make this work.)

Surprisingly, it is not that hard when you learn a few tricks. This module contains an activity called the Binary Game which will really help you get started. So, why wait?

Welcome to Data Link Layer!

Every network has physical components and media connecting the components. Different types of media need different information about the data in order to accept it and move it across the physical network. Think of it this way: A well-hit golf ball moves through the air fast and far. It can also move through water but not as fast or as far unless it is helped by a more forceful hit. This is because the golf ball is traveling through a different medium; water instead of air.

Data must have help to move it across different media. The data link layer provides this help. As you might have guessed, this help differs based on a number of factors. This module gives you an overview of these factors, how they affect data, and the protocols designed to ensure successful delivery. Let’s get started!

Welcome to Network Layer!

By now you may have noticed that the modules in this course are progressing from the bottom up through the OSI model layers. At the network layer of the OSI model, we introduce you to communication protocols and routing protocols. Say you want to send an email to a friend who lives in another city, or even another country. This person is not on the same network as you. A simple switched network cannot get your message any further than the end of your own network. You need some help to keep this message moving along the path to your friend’s end device. To send an email (a video, or a file, etc.) to anyone who is not on your local network, you must have access to routers. To access routers, you must use network layer protocols. To help you visualize these processes, this module contains two Wireshark activities. Enjoy!

Welcome to Address Resolution!

Hosts and routers both create routing tables to ensure that they can send and receive data across networks. So how does this information get created in a routing table? As a network administrator, you could enter these MAC and IP addresses manually. But that would take a lot of time and the likelihood of making a few mistakes is great. Are you thinking that there must be some way that this could be done automatically, by the hosts and routers themselves? Of course, you are correct! And even though it is automatic, you must still understand how this works, because you may have to troubleshoot a problem, or worse, your network could be attacked by a threat actor. Are you ready to learn about address resolution? This module has several very good videos to help explain the concepts, as well as three Packet Tracer activities to cement your understanding. Why wait?

Welcome to Basic Router Configuration!

Have you ever run a relay? The first person runs the first leg of the race and hands off the baton to the next runner, who continues forward in the second leg of the race and hands off the baton to the third runner, and on it goes. Routing packets is very similar to a relay. But if the first runner does not know where to find the second runner, or drops the baton in the first leg, then that relay team will most certainly lose the race.

Routing packets is very similar to a relay. As you know, routing tables are created and used by routers to forward packets from their local networks on to other networks. But a router cannot create a routing table or forward any packets until it has been configured. If you plan to become a network administrator you definitely must know how to do this. The good news? It is easy! This module has Syntax Checker activities so that you can practice your configuration commands and see the output. There are also some Packet Tracer activities to get you started. Let’s go!

Welcome to IPv4 Addressing!

Currently, there are still plenty of networks using IPv4 addressing, even as the organizations which use them are making the transition to IPv6. So it is still very important for network administrators to know everything they can about IPv4 addressing. This module covers the fundamental aspects of IPv4 addressing in detail. It includes how to segment a network into subnets and how to create a variable-length subnet mask (VLSM) as part of an overall IPv4 addressing scheme. Subnetting is like cutting a pie into smaller and smaller pieces. Subnetting may seem overwhelming at first, but we show you some tricks to help you along the way. This module includes several videos, activities to help you practice subnetting, Packet Tracers and a lab. Once you get the hang of it, you’ll be on your way to network administration!

Welcome to IPv6 Addressing!

It is a great time to be (or become) a network administrator! Why? Because in many networks, you will find both IPv4 and IPv6 working together. After the hard work of learning to subnet an IPv4 network, you may find that subnetting an IPv6 network is much easier. You probably didn’t expect that, did you? A Packet Tracer at the end of this module will give you the opportunity to subnet an IPv6 network. Go ahead, jump in!

Welcome to ICMP!

Imagine that you have an intricate model train set. Your tracks and trains are all connected and powered up and ready to go. You throw the switch. The train goes halfway around the track and stops. You know right away that the problem is most likely located where the train has stopped, so you look there first. It is not as easy to visualize this with a network. Fortunately, there are tools to help you locate problem areas in your network, AND they work with both IPv4 and IPv6 networks! You will be happy to know that this module has a couple Packet Tracer activities to help you practice using these tools, so let’s get testing!

Welcome to Transport Layer!

The transport layer is where, as the name implies, data is transported from one host to another. This is where your network really gets moving! The transport layer uses two protocols: TCP and UDP. Think of TCP as getting a registered letter in the mail. You have to sign for it before the mail carrier will let you have it. This slows down the process a bit, but the sender knows for certain that you received the letter and when you received it. UDP is more like a regular, stamped letter. It arrives in your mailbox and, if it does, it is probably intended for you, but it might actually be for someone else who does not live there. Also, it may not arrive in your mailbox at all. The sender cannot be sure you received it. Nevertheless, there are times when UDP, like a stamped letter, is the protocol that is needed. This topic dives into how TCP and UDP work in the transport layer. Later in this module there are several videos to help you understand these processes.

Welcome to Application Layer!

As you have learned, the transport layer is where data actually gets moved from one host to another. But before that can take place, there are a lot of details that have to be determined so that this data transport happens correctly. This is why there is an application layer in both the OSI and the TCP/IP models. As an example, before there was streaming video over the internet, we had to watch home movies in a variety of other ways. Imagine that you videotaped some of your child’s soccer game. Your parents, in another city, only have a video cassette player. You have to copy your video from your camera onto the right type of video cassette to send to them. Your brother has a DVD player, so you transfer your video to a DVD to send to him. This is what the application layer is all about, making sure that your data is in a format that the receiving device can use. Let’s dive in!

Welcome to Network Security Fundamentals!

You may have already set up a network, or you may be getting ready to do just that. Here is something to think about. Setting up a network without securing it is like opening all the doors and windows to your home and then going on vacation. Anyone could come by, gain entry, steal or break items, or just make a mess. As you have seen on the news, it is possible to break into any network! As a network administrator, it is part of your job to make it difficult for threat actors to gain access to your network. This module gives you an overview of types of network attacks and what you can do to reduce a threat actor’s chances of succeeding. It also has Packet Tracer activities to let you practice some basic techniques for network security. If you have a network, but it is not as secure as possible, then you will want to read this module right now!

Welcome to Build a Small Network!

Hooray! You have come to the final module in the Introduction to Networks v7.0 course. You have most of the foundational knowledge needed to set up your own network. Where do you go from here? You build a network, of course. And not only do you build one, you verify that it is working, and even troubleshoot some common network problems. This module has labs and Packet Tracer activities to help you practice your new skills as a network administrator. Let's get going!