Basic Principles of Networking

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Introduction

Have you ever thought about connecting more than one computer to your broadband connection? As we all become increasingly reliant on computers and digital "connected devices" at home and work, being able to understand how to hook these systems up to our broadband connection will:

• Save us time (no more "trial & error" or having to wait for our "expert" friend to come around to help)
• Increase our enjoyment of broadband (e.g. hook up our XBox, Playstation or digital media device)
• Improve our kudos with friends, family & co-workers:- now you will be seen as the expert

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Contents

• Introduction
• Objective
• Why Network?
• How Difficult Is It to Create and Own a Network?
• Getting Started: How a Network is Like a Telephone System
• A Typical Telephone System
• Similarities of a Computer Network
• Network Everything!
• Protocol: Talking the Same Language
• Your Device: How It Is Known on a Network
• Summary

Objective

On reading this article you should understand

• Some of the possibilities of networking
• Common difficulties & obstacles
• The basic principles of how networks operate

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Why Network?

Hooking up computers and devices to each other and a broadband connection makes good sense. If our devices are all able to communicate with each other and the outside world, we can share our broadband connection amongst our family at home or colleagues in the office. It means that, for example, we can share a single broadband connection in our home with multiple computers and/or devices (e.g. Dad can work from home whilst, at the same time, the kids are playing online games).

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How Difficult Is It to Create and Own a Network?

Setting up a network is easy if you have a basic understanding of the concepts involved. However, it can be difficult if you try doing it without sufficient preparation and research. Simply buying networking hardware, connecting it all up and hoping for the best just simply doesn't work in most cases!

Similarly, if you "blindly" follow one of the many “Step-by-Step” guides (either in product manuals or online), you may find that, in situations where your equipment configuration doesn't match that of the example, you may struggle.

The Broadband-help.com series of networking guides© is different in its approach. It focuses more on providing enough education so that you'll be able to rig networks without having to resort to step-by-step examples. More importantly, you'll have enough understanding of what's going on to be able to maintain, extend and fix your network when things (as the inevitably do) go wrong!

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Getting Started: How a Network is Like a Telephone System

A Typical Telephone System

Most of us use telephones in our daily lives. Think about some of the things that make up a telephone system. We have:

• Telephone(s) (let's call them a "devices" from now on)
• The bit in the middle (e.g. cables, telephone exchanges etc)

In addition to the physical bits and pieces (devices, exchanges etc), we have to be able to connect phones together by a dialling system that is addressed by using telephone numbers. Diagram 1 show us a typical phone system. Computer networks are very similar to telephone networks. If you think about how a telephone system works, you'll very quickly be able to understand the basics of a computer network.

Let's now explore the similarities with a computer network.

Similarities of a Computer Network

Diagram 2 now shows the basic elements of a telephone system and a computer network. You should hopefully be able to spot some similarities between the two.

In the computer network you'll notice that it doesn't have a "telephone number". Instead it has a number (or designation) called "IP". More about IP soon.

Let's pick up on some more key points of similarity between telephone and computer network systems.

• A telephone system doesn't care which brand of "device" that you use. The same thing applies to a computer network:- the network doesn't care if you are using PC, Apple, PDA, XBox or even a connected fridge-freezer. It's all the same to the network!
• Only when you've established a connection (i.e. both parties pick up the phone) you can have a conversation on the phone. It's the same with a network:- a connection between devices must be established before devices can communicate.
• If you don't know someone's telephone number, what do you do? Well, you'll reach for a phone book (or directory) to look up their number right? Well, the same thing happens in computer networks:- You probably aren't going to remember an IP address but are more likely to remember an address such as "www.bbc.co.uk". So, like the telephone system, a directory(more on this later) is used to lookup the number (or IP) of the computer that you want to connect to. The only difference is that the directory lookup happens behind the scenes (i.e. you don't need a big paper phone book :) )

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Network Everything!

As we've already mentioned, computer networks don't care what is connected to them. Some of the possibilities are:-

• Computers (PC, Apple Mac, Solaris, Unix and so on)
• Personal Digital Assistants (PDA's)
• Inernet telephones (sometimes called "VOIP")
• Games machines (e.g. XBox, PS)
• "Clever" domestic appliances (e.g. fridges that shop for you)

The good news for us is that, as we're learning the basic principles of networking, that hooking up any or all of these devices will be no problem at all for us!

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Protocol: Talking the Same Language

Before we go any further, we need to introduce a new concept to you. It's the concept of a "protocol". The best way to help you understand this concept is by thinking about a real life example of what a "protocol" is.

Let's imagine that you want to call me (yes, we're back to that comparison again!) on the phone. How would we go about describing how a telephone call happens. Perhaps is could be something like the following:-

• You look up my number in the phone book
• Pick up the phone
• Dial the number
• Wait for me to answer
• We have the conversation
• At the end of the conversation, we both hang up

Guess what we've just described? Yes, it's a "protocol" for holding a telephone conversation!

A "protocol" is simply a description of the method by which devices (or humans) communicate between themselves.

Let's take another example. This time, we'll look at a conversation between two people (called Bill & Steve for the example) face to face. It might go like this:

• Bill says "HELLO Steve"
• Steve acknowledges Bill and says: "HI Bill"
• Bill & Steve hold a conversation (probably about MS Windows marketing strategies ;) )
• At the end of the conversation, Bill says: "BYE Steve". Steve says: "BYE Bill"

We've just given an example of a fairly standard conversation method which most people use every day. This standard way of communicating can be classified as another "Protocol".

When computers talk to each other over a network, it really is no different than the examples that we've given above. For this example, we are going to use Computer A that wants/needs to talk to Computer B (maybe to start an MSN messenger chat session?) The method goes as follows:

• Computer A: I need to communicate with Computer B. My user has an MSN Messenger item for a user on Computer B
• Computer A: What "number"/designation is Computer B on these days? Don't know- let's look in The Directory.
• Computer A: Aha, the directory says that Computer B is on number (e.g 169.145.72.9) at the moment!
• Computer A: I'm sending a request to Computer B on (169.145.72.9):- Request = "Let's Talk / Connect!"
• Computer B: Answers connection request from Computer A.
• Computer B: "Hi there Computer A, long time no connect. Ok, let's connect and exchange information"
• Computer A: "Great. Here's an MSN messenger item for your user"
• Computer B: "Thanks, got it! Nice chatting with you. Is there anything else?"
• Computer A: "Nope, that's it for now. See you later"
• Computer B: "No problem, Bye for now"
• Computer A disconnects from B

This type of "conversation" happens all the time between computers on networks. If you are reading this web-page, this type of conversation just happened between your computer and our web server.

This method of communication is STANDARD between devices on a network. The PROTOCOL is the sequence and method by which devices communicate. You will have probably noticed that for this to work, all devices must communicate in the same way. This means that they have to follow Standards.

One of those STANDARDS(or protocols) is called "Internetworking Protocol"(or IP for short).

Got it so far? It's really not that difficult is it?

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Your Device: How It Is Known on a Network

In the last section, we introduced you to the term IP. One of the components of IP is your computers designation (similar to a telephone number) or IP address.

Your computers IP Address is made up of four numbers each separated by a dot. It will look something like this: 169.158.2.1. If you are curious about what your real IP Address is, we have an online tool that tells you what it is at the moment.

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Summary

We've covered a lot of ground. By now you should understand the following:-

• What and "why" a network is
• What a protocol is & the importance of standards
• A basic understanding of your computers IP address

Remember that the objective of these networking articles is to give you enough knowledge to create, maintain and extend your own networks at home or office. However, we're not quite there yet but if you've understood things this far you've made a great start! Please keep a look out for the next in this series of networking articles where we start to introduce some more important concepts that will help you get more enjoyment from your broadband by understanding and implementing easier networking.

In the next part in this series, we explain some of the most important concepts in networking. Read TCP/IP Explained.

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