Packet Switching

Firstly, what is a packet?

When data is transmitted, it is split up into smaller chunks called packets. Each packet will contain 3 things, these are:

  1. The source address of the packet.
  2. The destination address.
  3. The data itself .

Packet Switching

Packet switching is the method of how the internet works. It is a method of data transfer, in which data is broken down into packets and then reassembled at its destination. Each packet will move from router to router accross a network until it reaches its destination, always taking the optimum route.

The Steps a Packet Takes (in short):

  1. Data is split into chunks (packets).
  2. Each packet has a to and from address and data.
  3. The order of packets is noted.
  4. Packets sent onto the network move between routers, taking an optimum route.
  5. Once packets reach there destination they are re-ordered.
  6. The recipitent will send a confirmation message.
  7. If a confirmation message is not recieved the data will be sent again.

Domain Names, URI’s and IP Addresses

What are URL’s, URN’s and URI’s?

  • URL-Universal Resource Locator

A universal resource locator is used to provide the location of a resource on the internet. It is important to know that any URL is considered a URI.

  • URN-Universal Resource Name

A universal resource name provides the name of the resource in question, allthough it does not provide any details about locating the resource.

  • URI-Universal Resource Identifier

The universal resource identifier can be either a URL, URN or it can be a combination of both.

An example of a URL (URI) is: https:// www .youtube.com/watch?v=2sb0Mr9wA-U

  • https:// Is the protocol
  • www. youtube.com/ Is the hostname (Domain Name)
  • watch?v=2sb0Mr9wA-U Is the location of the file on the server (Pathname)

It may also be important to note that the www in a website is known as a subdomain.

What is a Domain Name?

A domain name is a part of a URL which is used to identify an IP address, this can be seen above in the example of a URL. A domain name also gives the user information, this is done through the top level domain (TLD).

An example of a domain name is youtube.com. The top level domain is the .com and the second level domain is the youtube.

 bbc.com This is a commercial organisation called bbc
en.wikipedia.org This is an organisation, called wikipedia, requesting the english language.
gov.uk This is a governmental organisation in the united kingdom.

What is an IP Address?

It is important to know that an IP address also has a structure, like the URL and domain name. An IP address is split into 4 bytes (1 byte = 8 bits), meaning a IP address is 32 bits long.

00000000.00000000.00000000.00000000 – 11111111.11111111.11111111.11111111 (Binary)

0.0.0.0 – 255.255.255.255 (base 10)

An IP address is also split into two parts, a network and host identifier. The first two bytes is the network identifier and the second two is the host identifier.

Internet Registrars and Registries

Internet Registrars – These allow organisations and individuals to buy their own domain names.

Internet Registries – These hold domain names which are registered. They allow owners to link domain names to IP addresses.

Some domains are linked to multiple IP addresses, this is because the website may have users from all around the world. Having multiple addresses around the world allows the company to route them to the closest IP, giving them a faster and more stable connection. This also allows big sites to manage traffic through load balacing.

How Does a Domain Name become an IP?

This information can be found in a blog post I have already created here!


Websites that go into more detail into the subjects above.

URN, URL and URI’s.

Domain Names.

How a Domain Name is Returned as an IP

How a Domain Name is Returned as an IP

Domain Names were created so that users could easily access and navigate between websites without having to remember all the IP addresses for them. Whenever you access a website by inputting a domain name into the address bar of a browser, the corrosponding IP for that address will be retrieved. The following process outlines how this happens.

When you type a domain name into your browser address bar, such as google.com, a query will be sent to retrieve the IP address.

Use the featured image above to help you understand!

  1. The first server that your query encounters is the RR (Recursive Resolver), which is hosted by your ISP (Internet Service Provider).
  2. The RR will send the query to the Root DNS server, which holds all the information about Top Level Domain (TLD) servers.
  3. The query will then find its way to the correct TLD server, in this case for google.com it will be the .com TLD server. The server will then send you the IP of the hosting server in which google.com is located.
  4. Next your query will be sent to the DNS server hosting the domain and the IP will be returned to the RR.
  5. Finally the RR returns the IP address to the browser on your computer and then your browser can send a request to the IP to retrieve the websites content.

The query in this example would be “What is the IP address for the website domain google.com”.


This Website was very useful in helping me understand the process.

Setting up a Website

Setting up a Website

Steps to follow

  1. Register the domain with an internet registrar.
  2. IP address linked to domain name with a DNS.
  3. Webpage written in HTML.
  4. CSS to control layout and presentation.
  5. FTP set to run on port 20/21.
  6. Upload the website to the hosting server through FTP.
  7. Search engine optimization (SEO) to allow user to easily find site.

Things to consider

  1. Security of the website and server
  2. Geographical location of the hosting server in comparison to the clients accessing the websites location.