iGCSE Computer Science - Distance Learning

Tutor Marked Assignment 6
Tutor Marked Assignment 8 (Programming)

The Internet – Network Addressses

When identifying a device on a network we use two different types of address : IP address and MAC address. whilst it may seem sensible just to use one type of address, the IP address and MAC address are used for different purposes and often in combination.

network interface card

Every device that is able to connect to a network contains a network interface card. This internal piece of hardware allows the device to perform a handshake with main network connection device (usually a router or wireless access point). Part of this handshake is to provide the device’s MAC address and for the router to assign the device and IP address within the network.  

IP Addresses

ip address

IP addresses are made up of a number of 8 bit binary numbers usually represented in denery separated by full stops. There are two types of IP address : IPv4 which uses four 8 bit binary numbers and IPv6 which uses six 8 binary numbers.

When using the internet, the IP address of the network router is visible to the webserver and called the public IP address.

IP addresses are known as dynamic addresses. This is because the router will assign the next available IP address to the device as it joins the network and this address is then removed from the device as it leaves the network. This means that even though there are a finite number of addresses available, they can be reused as devices join and leave.

Activity

Use a website, or your command line tools to look up your own IP address. Once you have found it, calculate what it looks like as a binary address.

Eg. 192.0.0.1 would be: 11000000.00000000.00000000.00000001

MAC Addresses

laptop wifi

The MAC address, or Media Access Constrol address of a device is a static address. This means but the MAC address for the device never changes as it is hard coded into the network interface card.

Because each MAC address must be completely unique, they are often much longer than IP addresses and are often represented using hexadecimal instead of denary.

One useful part of having a MAC address is that it allows the network to uniquely identify any device. Should that particular device (or user) have caused an issue in the past, the MAC address can be used by the network manager to ban them from connecting to the network.

Creating this list of banned MAC addresses is known as MAC address filtering and can be set up by using a blacklist which holds a list of banned MAC addresses or by creating a white list which holds a list of allowed MAC addresses.

Revision Task

Download, print and complete the revision notes below. Don’t forget to add colour to the key words and your own notes in the areas indicated.