- Devices on a network send and receive data, a device needs an address to ensure it sends data to the correct place
- There are two types of network address systems:
- IP Address
- MAC Address
IP Addressing & MAC Addressing (OCR GCSE Computer Science)
Revision Note
Author
Robert HamptonExpertise
Computer Science Content Creator
IP Addressing
What is an IP address?
- An IP (Internet Protocol) address is a unique identifier given to devices which communicate over the Internet (WAN)
- IP addresses are dynamic, they can change
- IP addresses make it possible to deliver data to the right device
- A device connecting to a network will be given an IP address, if it moves to a different network then the IP address will change
IPv4
- Internet Protocol version 4 is represented as 4 blocks of denary numbers between 0 and 255, separated by full stops
- Each block is one byte (8 bits), each address is 4 bytes (32 bits)
- IPv4 provides over 4 billion unique addresses (232), however, with over 7 billion people and countless devices per person, a solution was needed
IPv6
- Internet Protocol version 6 is represented as 8 blocks of 4 hexadecimal digits, separated by colons
- Each block is 2 bytes (16 bits), each address is 16 bytes (128 bits)
- IPv6 could provide over one billion unique addresses for every person on the planet (2128)
MAC Addressing
What is a MAC address?
- A MAC (Media Access Control) address is a unique identifier given to devices which communicate over a local area network (LAN)
- MAC addresses are static, they can never change
- MAC addresses make it possible for switches to efficiently forward data to the intended recipient
- Any device that contains a Network Interface Card (NIC) has a MAC address assigned during manufacturing
- A device connecting to a local network already has a MAC address, if it moves to a different network then the MAC address will stay the same
- A MAC address is represented as 12 hexadecimal digits (48 bits), usually grouped in pairs
- The first three pairs are the manufacturer ID number (OUI) and the last three pairs are the serial number of the network interface card (NIC)
- There are enough unique MAC addresses for roughly 281 trillion devices
Worked example
Computers in a network can be identified using both IP addresses and MAC addresses.
Describe two differences between IP addresses and MAC addresses [2]
Answer
- IP address is dynamic/can change // MAC address is static/cannot change
- IP address is used to communicate on a WAN/Internet // MAC address is used to communicate on a LAN
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