Wednesday, 28 December 2011

Converting IPv4 addresses into Binary (Hard)

What is Binary?

Binary is the language that the computer speaks in and it consists of zero's and one's e.g. 110100101101.

Without a protocol, these numbers would mean nothing. You need to tell the computer how to read the numbers e.g. 1010101111010 could mean nothing if the computer read it as text but a butterfly if read as a picture.

Converting Binary into an IP4 and vise versa.

A IP4 address is made up of 32 bits (4 bytes) and consists of 4 sets of numbers that are 8 bits each (one digit is one bit - 11010010 = 8 bits/1 byte).

An IP address = which would look something like 11001100.10100101.01101010.00101101 in binary.

The biggest IP address you can get is

To convert an IP into binary, you simply use the 8 numbers below to add up to the byte you want to convert.




128 goes into 192, so we put a 1. We are now left with 64.
then we go to the next number along which is a 64.
64 - 64 = 0 so we put a 1.
We have now reached 192 by adding the first 2 numbers together.
Our conversion should look like this - 11000000.

11000000 = 192.
1     1   0   0   0 0 0 0

And to convert it back you do the reverse.

This is quite hard to understand, especially because i am writing it down.

As always, if you have any questions please comment and i will answer you.

Tuesday, 27 December 2011

Factors that influence webstie performance.

 Some Factors that influence website performance.
These are some factors that have to be taken into consideration when wanting to improve/create a connection or site. 
Clients side (your machine) - 

Bandwidth/quality of connection - the connection speed you have to the internet is going to be a huge factor in the time it takes to load webpages.
distance from the exchange - the further the distance the lower the connection quality as the request has to travel further.
Browser - some browsers are much faster than others (some are built for speed and some are built for utility)
Cache - some browser's caches are better than others (cache remembers graphics/text on a website so it doesnt have to be downloaded again)
PC performance - RAM, processor power etc. The better hardware you have the faster the requests can be sent to the webserver and the faster they can be recieved.
Anti virus software can slow down if the site has to be scanned before hand.
network interface card - the better (bigger bandwidth it can hold) N.I.C is the faster the connection will be.
Wireless - is there any interferance from anyother wireless devices and how far away from the router is the computer.
Wired cables - is there any interferance to the cabling (ethernet, UTP)

Server side - 

Number of clients accessing that site at any given time - The more people you have trying to access your website the more slower the site will become (this factor depends on how much bandwidth/traffic your shared/dedicated web host has to use.
DOS attacks - denial of service attacks are where someone requests a lot of information from the web server that the website cant handle so it goes down and noone else can use it 
Amount of content/media and the size e.g. a page with hundreds of images on it will load slower than one with just text.
Quality of the code (HTML, CSS) - The speed can be increased if the code is well written.
Qualtiy of server software - The server software could slow down the site.
If the web server is shared or dedicated. If the server is shared then you are sharing web space with other websites so your bandwidth will be limited whereas if your site is being hosted on a dedicated server then it has as much bandwith as that server can provide.
Web server hardware - the speed of the server RAM, processor is like the computer. The faster they are, the faster the clients webpage requests will be answered.

Monday, 26 December 2011

Cloud computing

What is Cloud computing?

Cloud computing is where you focus less on the physical hardware and more on storing information/ websites/ data online. Cloud computing is where you pay someone to host a server and but you only pay for what you use. E.g. when you buy a 10TB server and host your website on their. You are paying to run that server whereas with the cloud you only pay for what you use.

Costs less – Pay for what you need    You giving someone else your information/ data and trusting them to keep it safe.     
Scalable – can increase/ decrease storage when needed    Security, you are trusting someone to keep your data secure.     
Access data from anywhere         

  Localized storage   

You are in control of your own data


    Expensive to maintain and run     
    costs more if you need more space     
    You pay whether you are using the space or not.     
    Can only access your data when you are in that network     
    If the physical hardware is damaged (fire, water, stolen etc.) you can’t get it back    

Cloud Computing


Costs less – Pay for what you need
Scalable – can increase/ decrease storage when needed
Access data from anywhere


You giving someone else your information/ data and trusting them to keep it safe.
Security, you are trusting someone to keep your data secure.

Sunday, 25 December 2011

IP Addresses and TCP/IP model (Hard)

IP Addresses

 What is an IP address?

 There are two types of IP addresses. We have used IPv4 addresses up until now but we are running out of IP addresses to give, so we have created IPv6 addresses. The "4" and the "6" relate to how many bits are in the address e.g. 4 = (total of 32 bytes). IPv6 addresses also include letters as well as numbers.

An IP address is given to each device whenever it accesses a network e.g. Think of it as the computers identification.

What is the format of an IP address?

The format of an IP address consists of 4 different numbers separated by a full stop. Each number is a byte or 8 bits (total 4 bytes and 32 bits) The number is written in binary (01011) so the maximum number available as an IP address is

Difference between a class A, B and C IP address.

Class A –  Each IP has a specific location that it is assigned to. They use the location and the network it will connect to. ( 192 would be the network it connects to)  Class A Is given to very large companies as there are a lot of IP addresses available.
Class B –  Is given to service providers and small companies like a college.
Class C – Is given to small to mid-size companies.

What are the four layers of the TCP/IP model?

The four layers of the TCP/IP model are –
Network access layer

Function of each of the four layers in the TCP/IP model with examples of Protocols for each layer.
Application layer –  This layer is what the user uses to send/request the packets e.g. FTP, SMTP.
Transport layer – Sends the packets to the destination. This layer is responsible for checking to see if the packets arrived uncorrupted e.g. TCP/IP, UDP.
Internet layer – Responsible for sending the data over a network.
Network access layer – This is used to transfer data to different nodes on a network e.g. Ethernet, IEEE 802.11 wireless LAN.

Saturday, 24 December 2011

Hardware Introduction (Beginner)

Differences between Desktops and Laptops

  • Desktops are easily upgradeable whereas a laptop can be very difficult.
  • Desktops usually have better components than laptops meaning they are used for tasks that would be near impossible to run on a laptop
  • Desktops are not portable whereas laptops can be taken wherever you go
  • Laptops are used for word processing, games that don't require a lot of computer power, and browsing.
  • Desktops are used for video/photo editing, gaming (where graphics and frames per second count), and everything the laptop can do.

Computers need both hardware and software. Software couldn't be run without hardware and without software, hardware would be totally useless.

Hardware is everything you can touch that is related to the computer e.g. a USB stick or a motherboard.


Peripherals are any device that can connect to the computer but is not required for it to work.

Examples of peripherals would be...

  1. Keyboard
  2. Mouse
  3. Monitor
  4. Speakers
  5. USB
  6. Printers
  7. Scanners
  8. Webcams
  9. Microphones
  10. Speakers

 USB (pendrive, flashdrive, storage stick)

Universal serial bus and other mass storage device's allow for extra data to be stored. You can take these USB sticks and external hard drives everywhere you go and use them to back up any important work you have.

Friday, 23 December 2011

Sizes and Packets (Hard)


8 bits = 1 byte
1024 bytes = 1 Kilobyte (KB)
1024 Kilobytes = 1 Megabyte (MB)
1024 Megabytes = 1 Gigabyte (GB)
1024 Gigabytes = 1 Terabyte (TP)

When a Device wants to send a message to another device, the information is sent in envelopes called packets. Packets are 8 bits or 1 byte in size.

Each packet is sent simultaneously unless the connection is broken.

Packet structure

A packet is broken into 3 parts; Header, body, and footer.


Senders IP address - Address of where the packet was sent from.
Destination IP address - Where the packet is going.
Protocol - What protocol its using.
Sequence number - Messages are too large to be sent in one packet so they are sent in multiple packets. The packets don't arrive at the destination in the right order so each packet is given a sequence number so that it can be put back into the right order when it gets to the destination.

packet send order = 3,2,4,1
packet receive order = 3,2,4,1
packets order after sequence number has been read = 1,2,3,4


This is where the data being sent is stored.


Error correction -This is where the packet gives information to the receiving device to figure out if the data is corrupt or not (I will go over this in the protocol and general tutorial
Data to show end of packet - This information tells the device that it is the end of the packet.

To sum up.

  • Packets are 8 bits in size (1 bytes)
  • Packets contain a  header, body and footer.

Tuesday, 20 December 2011

Types of communication (Medium)

Types of communication

When devices communicate they use one of three methods; Simplex, half-duplex and duplex (full duplex).

Simplex communication is one way communication. A television remote uses infrared to communicate with the television, This is simplex communication as the television isn't communicating back. In other words, simplex communication is like a single lane full of traffic where no other cars can come through the other way. Another example would be a keyboard or a mouse.

Half - Duplex is where devices can talk to each other but not at the same time. Imagine a single lane with traffic lights. A walkie talkie uses half duplex communication.


 Duplex communication is where there are two lanes of traffic and both lanes can go in their own direction at the same time. An example of duplex communication would be a mobile phone

Saturday, 17 December 2011

ISP's, Web hosting and Requesting a web page (Medium)

 ISP's and Requesting a webpage.

The ISP (Internet Service Provider) is what you need in order to connect to the internet.
Different ISP’s offer different deals and speeds. Orange, sky, Tesco and BT are all ISP’s and all have different speeds and deals depending on your location. Some ISP’s provide you with web hosting, domain names, routers and your own email e.g.

Web hosting is where you host your website on a server. You can host a website on a server that you own but this requires knowledge and time. Most websites have their sites hosted by companies offering web hosting services.

Web Hosting Services

Web hosting is where you buy space on someone’s server that allows you to host a website.

The website is hosted on a server which you access when you go to that web address. There are 2 types of web hosting servers – shared or dedicated. Shared means your website is being hosted on the same server as other peoples so you will have more limitations than dedicated servers such as bandwidth, traffic, web space etc. With a dedicated server you have a server for yourself and don’t share it with anyone so the security is much better and you don’t have to share bandwidth, traffic or web space with anyone else.
Web hosting service is aimed at people who don’t have time or knowledge to host their website on their own server.
Depending on what site/server you choose to host with you will get different deals such as bandwidth, server space, traffic and domain names.

Some of the other features offered by web hosting sites are

Sub domains these can be limited or unlimited

Money back – some web hosting sites offer an anytime money back guarantee and others give a limited time.
Email – some companies offer an option to have your own email address such as

Site builder – this is where you use the sites tools to create your webpage if you don’t know any code to do it yourself. This makes the design of the website much easier but it means you have to use a premade theme design.

SSL certificate – Secure socket layer. This provides encryption between the web server and the internet (browser) to make sure that all data is secure.

An example of a site that allows you to buy web space on their servers would be Sites like this provide package deals such as web hosting and domain names included.

Domain Name Registration

In order to make the website go live it needs an address so that people can view it. The domain name is the name of the site so it should be relevant to your company name
e.g. so that people can easily find your site when they search for it.
A domain name can be bought from domain name registrars online such as
When people type in a web address into the address bar in their browser, a message is sent to their ISP and then onwards to the DNS (Domain Name Servers) which translates the domain name entered into the actual address (to view a website you need to get the page from a webserver which is an IP address, the DNS looks at the address enters and finds the IP) and then sends that information back to your computer.

An example in detail.

The client enters in a web address such as “” this is sent to their router either through wired or wireless connection . It is then sent to the clients ISP which allows them to connect to the internet e.g. Talk Talk, BT and Orange etc.

Before you can access the webhost server you need to look up the actual address of the site you want to visit. The actual name of the server you want to go to is an IP address but it is much easier to remember names than a long list of numbers. The DNS server takes the name of the site you want to go to and looks up the IP address and then sends that information back to the client through the clients ISP.
Once the client has the actual address of the website they can request information from it and the information of the page are sent back to the client’s computer.

Once they have been to the DNS to retrieve the real address of the web host server they then can access the web host server to retrieve the webpage which then displays inside your browser.  This all happens in a matter of seconds/milliseconds depending on your connection speed (broadband or dial up ect).

The main software tool the client uses to access a web page is a browser. A browser allows you to browse the internet. There are many different types of browser e.g.  Google chrome, Internet explorer, Safari, Opera.  This is where the webpage is displayed from the web host. All browsers use the same protocol - HTTP ( will go into protocols in later tutorials) this is a request and response communication method.

To sum up.
  •  ISP's (Internet service providers) - allow us to connect to the internet.
  • Shared severs - where your site is hosted with others.
  • Dedicated servers - Where you have a server for yourself.
  • A website name is not its "actual" address. A real address is a IP address of the web server its hosted on e.g. - We use names instead of numbers as names are much easier to remember.
  • DNS = Domain name servers
  • Method of viewing a webpage is....   Enter web page address e.g message is sent from your computer to your router, through your ISP and to your DNS where the name of the website you entered is checked in a database to find its "actual" address. The "actual" address is then sent back to your computer where it request the webpage from the webserver with the address it just received from your DNS. The webpage is requested and then shown into your browser.
Thank you for reading, If you have any questions i will be happy to answer them.

Friday, 16 December 2011

Network Devices (Medium)

Network Devices

 There are many devices that can be used in a network and they all have different uses.

Your home network will have a router, computer/laptop (host) and other devices such as ipods, xbox, printers etc. These will all be connected to the router via a Ethernet cable or wireless.

Devices on a network explained.

Hubs – A Hub allows different nodes on a network to connect to each other via Ethernet cables or wireless. When one node wants to send a message to another, all the nodes on the network are sent the message and they all ignore it unless it is the node that it was meant to go to. It is inefficient to do it this way when you look at switches…

Fast Hub - A fast Hub connects two hubs together, creating 2 networks out of one.
Fast switch - A fast Switch does exactly the same as a fast hub except for switches.

Switches – Switches are like a Hub but when one node wants to send a message, the switch reads where the message is going to and sends it straight to that node. The other nodes don’t have to ignore the message. This is more efficient than the hub and wont send unnecessary packets.

Bridges – Bridges connect two  localized networks together. A bridge will look at the source address and destination address and decide whether to forward or filter the packet. It will look at a packet and see if it Is going to someone outside the network or someone in your network and if it has authorization.

Repeaters – Repeaters receive a message and repeat it at a higher strength. They do not break up the message, they recreate it and send it on again. The maximum number of repeaters you can use between two nodes is four. You cant use any more than four because there is not enough time to send a confirmation message back before another message is sent.

Routers – Routers are used to connect networks together e.g. the network you have at home ( computer, laptop, games console and IPod etc.) is connected to the Internet via your router (it has to go through the ISP before connecting though) This allows your devices on your network to request information from the Internet. They also filter out any unwanted packets going to your network through a port.

 Servers - Servers are used to manage resources on a network. This includes email servers, ftp (file transfer), web (web hosting), print server etc. 
Servers differ from hosts in that the server focuses on one specific task that you set it up with.

Printers - Devices that allow you to put an image from the computer onto paper or other material depending on what type of printer it is.

 Hosts - The computers on the network that are called hosts or nodes. 

Terminators - These go at the end of a bus network to stop the messages from bouncing back into the network and creating all kinds of problems.

All these devices play a different part. They can all be used together in a network to create a bigger network.

The technical name for the Ethernet cable is called RJ45.
The technical name for the phone line cable which gets plugged into your phone and router is called RJ11.

To sum up.

  • There are many different devices on a network and they all do different tasks.
  • The names of the devices are above, along with their description. ( Google them, learn what they look like and how to distinguish one from the other. I can't upload photos because i have't got any of these devices and copyright laws are crazy).
  • Ethernet cable = RJ45
  • Phone line cable = RJ11
If you have any questions, please comment below.

Thursday, 15 December 2011

Topologies (Medium)

Network topologies.

Network topologies are names for how the networks are setup (shape, description etc.)

The basic types of topologies are...

  • Bus.
  • Star
  • Tree
  • Ring
  • Mesh


A bus network can be described as one long network cable that has multiple cables coming off of it to the computers. Terminators are required at the end of the long network cable to stop any signals getting sent back.

Why you should have a Bus network.

It is cost efficient as you only need one cable.
Costs much less than other topologies
No hassle with tangled wires.
Easy to install.
Best suited for small networks.

Why you shouldn’t have a bus network.

If the cable gets damaged or broken the whole network will go down.
All computers on the network will share bandwidth so performance will be slow.
Limited cable length and hard to add new stations.


A star network is one central switch, hub or computer which all other workstations connect to the central device. This network topology is the most common of all the other networks and is best suited for computers that are scattered around and can’t be connected with an Ethernet cable.

Why you should have a Star network.

Better performance, unlike the Bus network or ring network because data lines aren’t being shared with other work stations.
Easy to install
No interruptions to the network if stations are added or taken away.

Why you shouldn’t have a Star network

If the central device fails the network will go down.
If one workstation is using up most of the central devices processing capacity.
Network size is limited to amount of workstations that can connect to the central device.
Performance of the network depends on the capabilities of the central device.


 A tree network is made when two or more star networks are connected.
If one star network (the central hub) goes down all the computers in that star network will be effected but the other star networks will not. It connects the different star networks together by a wire exactly like the bus network does to connect all the different work stations/nodes.

Why you should have a tree network.

Easy to add and remove stations
 You can add whole star networks at one time to the network.
Perfect for schools, universities and colleges.

Why you shouldn’t have a tree network.

A lot of cable is required.
The network can get really big and be hard to manage.
The length of the network depends on the length of the cable.


A ring network is a circle of computers that are all connected by one cable. Kind of like a bus network but the cable loops. In a ring network the data flows in all of the same direction, so there is no risk of packet collision.

Why you should have a ring network.

It’s faster than other network topologies because the data flows in one way.
Cheap and easy to expand.

Why you shouldn’t have a ring network.

If the ring is broken then the whole network will go down.
If extra workstations are added the network will slow down with more users.
Network adapter cards are more expensive than Ethernet cards or hubs.


Mesh networking is where workstations are used as independent router. This is so the data can get transferred to the target location in the fastest way possible. If one connection is blocked either by being offline or having a cable damaged the network will allow data too “hop” to another workstation to find the next quickest route. It can be called a self healing network because it will find a connection if the one it is using breaks down.

Why you should get a mesh network.

Self healing
Not dependent on a single switch or hub
Perfect for lots of workstations
If one connection fails the whole network does not go down.
No traffic problems
If one connection should fail it is easy to see where the failure happened as all nodes are connected to each other.

Why you shouldn’t have a mesh network.

A lot of cable is required to connect all the nodes together.
Can be difficult when trying to connect all nodes together.
Much more expensive than any of the other networks.

All network topologies have their advantages and disadvantages. They are all used in businesses, some more than others but it ultimately depends on what you want the network to do. I you want the network to be stable, a mesh network would be the most reliable or if you want a home network, then the star network is efficient.

Wednesday, 14 December 2011

What are networks? (Beginner)

If you are viewing this page then you are connected to the internet.

What is the Internet?

The internet is a network of networks (a connection of networks that are joined together)

If you could see the internet, it would look something like this. 

The circles represents a web server.
The point of this image is to demonstrate that no one controls the internet. When you (one of the squares) connects to Google (blue circle) you are connecting straight to their web server and requesting the page. When you search for YouTube through Google and click the link you are being sent to another web server (not always the circle next to it)

 The Internet is a mesh of networks. "Mesh" is a network topology and i will cover it in the medium network tutorial.

Home networks vs Business networks.

There is a difference between home and business networks as the purpose and requirements are different.

A home network is mainly used to connect to the internet and to other devices on your network (connecting your smartphone to your computer etc.)

Whereas a business network is mainly focused on connecting multiple computers together (depending on the size of the business, networks can have a range of 5-600+ computers on the network)

Your home network will look something like this...

Artistic drawing of a typical home network.

In this picture we see a number of devices connected to the router via wired or wireless connection.
The router is the gateway to the internet.

A simple business network will look something like this...

Artistic drawing of a simple business network.

In this network we have a number of computers connecting to a switch.

A switch allows multiple devices to talk to one another.
When Pc-1 wants to send a message to PC-2, the message goes through the switch and onto PC-2.

Also on the network we have a server. Servers can do different things depending on how they are set up. For example,  they can be an email server, a web server, dynamic host control protocol, domain name server etc. (Don't worry if you don't know what those last two are, they will be explained in the medium network tutorial)

Ports are the slots where cables go to allow devices to connect to them. Ports can be found on your router, switch, hub, and computer.

Switches have a lot of ports, but if its a big network the switch can connect to another switch to allow more devices on the network.
If we have a router connected then all of the computers on this network will be able to connect to the internet.

To sum up.

  • The Internet is a network of networks.
  • A router connects networks together and is a gateway to the internet.
  • A switch is a device that allows other devices to communicate with each other.
  • A port is where the cable fits into which in turn allows connections to be made.
  • Servers are used for many different tasks depending on what you need them for.

If you have any questions, feel free to ask below :)


Hi, my name is Riley and i have decided to create a blog on everything i know about computers. When i first started learning about computers and networking, the websites weren't that helpful and were all laid out in massive chunks of text which was a pain to scan through.

In my tutorials i will try my hardest to explain everything as detailed and as simply as possible.