Networking
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
Objective
On reading this article you should understand the following concepts and their significance to setting up a home or small office network:
· Some of the possibilities of networking
· Common difficulties & obstacles
· The basic principles of how networks operate
· IP Address
· IP Subnet Mask
· Default Gateway
The value to us in understanding these concepts is that we will easily be able to plan, create & maintain our own home or small office networks by ourselves (hence saving time & money compared to having to call in an external “expert”).
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).
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.
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!
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”.
A “protocol” is simply a description of the method by which devices (or humans) communicate between themselves.
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?
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.
TCP/IP – What Does It Mean?
TCP/IP stands for “Transmission Control Protocol / Internet(working) Protocol”. It is a description of a networking protocol that has evolved over several decades and is now the most widely used networking protocol. It is also the protocol that forms the “backbone” of the way the internet works.
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
Objective
On reading this article you should understand the following concepts and their significance to setting up a home or small office network:
· Some of the possibilities of networking
· Common difficulties & obstacles
· The basic principles of how networks operate
· IP Address
· IP Subnet Mask
· Default Gateway
The value to us in understanding these concepts is that we will easily be able to plan, create & maintain our own home or small office networks by ourselves (hence saving time & money compared to having to call in an external “expert”).
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).
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.
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!
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”.
A “protocol” is simply a description of the method by which devices (or humans) communicate between themselves.
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?
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.
TCP/IP – What Does It Mean?
TCP/IP stands for “Transmission Control Protocol / Internet(working) Protocol”. It is a description of a networking protocol that has evolved over several decades and is now the most widely used networking protocol. It is also the protocol that forms the “backbone” of the way the internet works.
An IP Address
Diagram 1 - Example of an IP Address
Diagram 1 shows an example of what a typical IP address looks like. Important things about an IP address are:
· There are EXACTLY(no more, no less) four numbers separated by a “period”(“Full Stop” in GB English).
· Each number MUST be equal or greater to 0 and no more than 255.
· We know that this IP address is on a “Private” network. (More on this later)
The example in Diagram 1 shows us a set of numbers that are easily read by humans. From your basic technology / science lessons at school, you know that computers and humans think in different ways.
· Computers: “Think” & communicate in ones and zeros (1 & 0)
· Humans: Think & communicate in diverse ways such as different cultural languages. Our number system is based on the concept of ten(10)
For the purposes of this article, we’ll stick to the human readable forms of expressing IP information. However, you need to be aware that, under the hood of the TCP/IP engine, computers are using and “seeing” IP addresses as a sequence of ones and zeros. Understanding the ones and zeros is only necessary if you get into complex “subnetting” (more on this later).
Host & Network Identifiers
Diagram 2 - Hosts and Networks
Networks are made up of two key things:
Computers / Devices
Referred to as HOSTS in network “speak”.
Networks
Simply called NETWORKS. A NETWORK is defined as a bunch of devices hooked up together to form a network.
Diagram 2 shows a very simple network of devices connected together. The important things that you need to understand at this point are:
· There are HOSTS and NETWORKS
· A HOST exists in a NETWORK
· A HOST can be any connected device (just like the diagram shows!)
In Diagram 2, we’ve shown the simplified model of a network. Now let’s see how this applies to a real life TCP/IP Network (e.g. one that you might set up at home or in the office).
Networks are made up of two key things:
Computers / Devices
Referred to as HOSTS in network “speak”.
Networks
Simply called NETWORKS. A NETWORK is defined as a bunch of devices hooked up together to form a network.
Diagram 2 shows a very simple network of devices connected together. The important things that you need to understand at this point are:
· There are HOSTS and NETWORKS
· A HOST exists in a NETWORK
· A HOST can be any connected device (just like the diagram shows!)
In Diagram 2, we’ve shown the simplified model of a network. Now let’s see how this applies to a real life TCP/IP Network (e.g. one that you might set up at home or in the office).
Diagram 3 - Hosts and Networks With TCP/IP Shown
Diagram 3 now adds some more information relating to actual TCP/IP.
You will notice that Network “N” is designated as 192.168.1.x. Sometimes, you’ll see this expressed with the “x” replaced by a zero(0):- It means the same thing.
So, we are getting quite close to understanding the basics about TCT/IP now! We should now understand how HOSTS are related to each other and to a network.
Having a network like this is great and means that all of our devices can talk to each other at home or in the office. However, the real advantages of networking come when we hook networks together. For example, at home or in the office, we might want to hook our network up to the Internet (it’s just another network!) so that all of our computers can send/receive email. Let’s look at this in the next diagram
Diagram 3 now adds some more information relating to actual TCP/IP.
You will notice that Network “N” is designated as 192.168.1.x. Sometimes, you’ll see this expressed with the “x” replaced by a zero(0):- It means the same thing.
So, we are getting quite close to understanding the basics about TCT/IP now! We should now understand how HOSTS are related to each other and to a network.
Having a network like this is great and means that all of our devices can talk to each other at home or in the office. However, the real advantages of networking come when we hook networks together. For example, at home or in the office, we might want to hook our network up to the Internet (it’s just another network!) so that all of our computers can send/receive email. Let’s look at this in the next diagram
Diagram 4 - Connecting up Networks
Diagram 4 shows nearly the same thing as diagram 3 in terms of an individual network. However, the main thing it shows is how multiple networks can be hooked up together.
If you’re sticking with this stuff so far, you might have noticed that we’ve sneakily thrown another device into the diagram. Yes, we admit it! It’s the ROUTER that now is now included in both networks. A router is simply another device connected to a network. It is responsible for “routing” any TCP/IP traffic to and from other networks. Every network that needs to “talk” to another network needs some form of router.
Note
Network “B” in the diagram could just as easily be The Internet in general. So, if we are thinking about how to hook our home or small office network up to The Internet, our network “N” would look very similar to diagram 4.
Now that we’ve come to the point where we understand what HOSTS and NETWORKS actually are, let’s relate this back to TCP/IP designations. Very simply put:
A HOST Identifier
Uniquely identifies a device on a network. For example, if your IP address on your network is 192.168.1.1, your HOST ID might be “1″
A NETWORK Identifier
Uniquely identifies your network. For example, if your IP address on your network is 192.168.1.1, your NETWORK ID might be “192.168.1.x”
Don’t worry if you don’t yet fully understand Network and Host identifiers. It will help you to read the next section (Subnet Mask).
Diagram 4 shows nearly the same thing as diagram 3 in terms of an individual network. However, the main thing it shows is how multiple networks can be hooked up together.
If you’re sticking with this stuff so far, you might have noticed that we’ve sneakily thrown another device into the diagram. Yes, we admit it! It’s the ROUTER that now is now included in both networks. A router is simply another device connected to a network. It is responsible for “routing” any TCP/IP traffic to and from other networks. Every network that needs to “talk” to another network needs some form of router.
Note
Network “B” in the diagram could just as easily be The Internet in general. So, if we are thinking about how to hook our home or small office network up to The Internet, our network “N” would look very similar to diagram 4.
Now that we’ve come to the point where we understand what HOSTS and NETWORKS actually are, let’s relate this back to TCP/IP designations. Very simply put:
A HOST Identifier
Uniquely identifies a device on a network. For example, if your IP address on your network is 192.168.1.1, your HOST ID might be “1″
A NETWORK Identifier
Uniquely identifies your network. For example, if your IP address on your network is 192.168.1.1, your NETWORK ID might be “192.168.1.x”
Don’t worry if you don’t yet fully understand Network and Host identifiers. It will help you to read the next section (Subnet Mask).
Subnet Mask
So far you will have learnt that there are HOSTS and NETWORKS and that a HOST exists in a NETWORK. Now we are going to put the final piece of the puzzle in place and talk about the Subnet Mask.
Diagram 5 - Subnet Mask Explained
Diagram 5 shows us an exploded view of a HOST on a NETWORK. The subnet mask simply defines which sections of an IP address are the NETWORK ID and which section(s) is/are the HOST ID. We’ve taken an example of a subnet of 255.255.255.0. You can use this example to set up your own network.
So, we should now be at a point where we understand that asubnet mask DEFINES the network to the HOSTS. For example, if HOSTS “A” and “B” are both connected together, and both have the same subnet mask defined they are deemed to be on the same network as each other.
Default Gateway
In the previous section, we discussed how a subnet mask DEFINES a network (by Network ID) to a HOST.
What happens when HOSTS have different subnet masks? Well, you guessed right if you were thinking that HOSTS with different subnet masks are considered to be on different networks!
Look back at diagram 4. For HOSTS in different networks to be able to connect and communicate, they have to communicate via a series of ROUTERS.
The Default Gateway is simply the address of the router on your network that is responsible for communicating with the outside networks.
Public & Private Networks
Public Network (Sometimes called a WAN)
The Internet is a public network. Every IP address on The Internet must be unique.(i.e. globally unique).
Private Network (Sometimes called LAN)
A private network could be like the one that you have at home or in the office. It may (optionally) be connected to a public network. IP addresses in a private network need to be unique but do not need to be globally unique.
It is important that you follow international standards when setting up private networks. You must use IP addresses that are in certain ranges so as not to duplicate ones already in use on public networks. This is particularly important where your private network is connected up to the internet:- It won’t harm The Internet but it will make your private network non-functional.
The standards (as defined by Internet Assigned Numbers Authority (IANA)) for private network addresses are:
· 10.0.0.0 to 10.255.255.255
· 172.16.0.0 to 172.31.255.255
· 192.168.0.0 to 192.168.255.255
· Also, IP addresses in the range of 169.254.0.0 to 169.254.255.255 are reserved for Automatic Private IP Addressing (such as in Windows XP)
Diagram 5 shows us an exploded view of a HOST on a NETWORK. The subnet mask simply defines which sections of an IP address are the NETWORK ID and which section(s) is/are the HOST ID. We’ve taken an example of a subnet of 255.255.255.0. You can use this example to set up your own network.
So, we should now be at a point where we understand that asubnet mask DEFINES the network to the HOSTS. For example, if HOSTS “A” and “B” are both connected together, and both have the same subnet mask defined they are deemed to be on the same network as each other.
Default Gateway
In the previous section, we discussed how a subnet mask DEFINES a network (by Network ID) to a HOST.
What happens when HOSTS have different subnet masks? Well, you guessed right if you were thinking that HOSTS with different subnet masks are considered to be on different networks!
Look back at diagram 4. For HOSTS in different networks to be able to connect and communicate, they have to communicate via a series of ROUTERS.
The Default Gateway is simply the address of the router on your network that is responsible for communicating with the outside networks.
Public & Private Networks
Public Network (Sometimes called a WAN)
The Internet is a public network. Every IP address on The Internet must be unique.(i.e. globally unique).
Private Network (Sometimes called LAN)
A private network could be like the one that you have at home or in the office. It may (optionally) be connected to a public network. IP addresses in a private network need to be unique but do not need to be globally unique.
It is important that you follow international standards when setting up private networks. You must use IP addresses that are in certain ranges so as not to duplicate ones already in use on public networks. This is particularly important where your private network is connected up to the internet:- It won’t harm The Internet but it will make your private network non-functional.
The standards (as defined by Internet Assigned Numbers Authority (IANA)) for private network addresses are:
· 10.0.0.0 to 10.255.255.255
· 172.16.0.0 to 172.31.255.255
· 192.168.0.0 to 192.168.255.255
· Also, IP addresses in the range of 169.254.0.0 to 169.254.255.255 are reserved for Automatic Private IP Addressing (such as in Windows XP)
Putting It All Together: An Example of a Small Network
Diagram 6 - Example Small Network
Diagram 6 shows a typical configuration of a home or small office network that is connected to the Internet by a Broadband Router.
You should be able to easily understand this example now. Let’s list some of the important features:
· All HOSTS are on the same network. We know this because they all have the same subnet mask of 255.255.255.0
· Each HOST has a unique IP address in its own network
· The maximum number of hosts that we can have on this network is 254
· Network traffic destined for other networks (i.e. The Internet in this example) is sent to the DEFAULT GATEWAY which is the router at 192.168.1.254 in this example
You can use this example to install and configure your own network and hook it up to a broadband router.
Diagram 6 shows a typical configuration of a home or small office network that is connected to the Internet by a Broadband Router.
You should be able to easily understand this example now. Let’s list some of the important features:
· All HOSTS are on the same network. We know this because they all have the same subnet mask of 255.255.255.0
· Each HOST has a unique IP address in its own network
· The maximum number of hosts that we can have on this network is 254
· Network traffic destined for other networks (i.e. The Internet in this example) is sent to the DEFAULT GATEWAY which is the router at 192.168.1.254 in this example
You can use this example to install and configure your own network and hook it up to a broadband router.
