Data Packets (Cambridge (CIE) O Level Computer Science): Revision Note

Data Packets

What are packets?

• Packets are small 'chunks' of data that make up a larger piece of data that has been broken down by the TCP protocol so that it can be transmitted over the internet

• TCP stands for Transmission Control Protocol and is used for organising data transmission over networks

• Small 'chunks' of data are easier and quicker to route over the internet than big 'chunks' of data

  • Routing involves finding the most optimal path over a network

• Data can include anything from text, images, audio, video, animations, etc, or any combination of these

What do packets contain?

• A packet consists of:

• To transmit the message “This is a message :)”over the internet, TCP might break the message down into 4 packets

• Each packet contains a:

  • source IP address

  • destination IP address

  • payload (the data)

  • a packet number

• Error checks make sure that when a packet is received there is minimal or no corruption of the data

• Corruption is where packet data is changed or lost in some way, or data is gained that originally was not in the packet

• Read error detection methods for more detail on how data packets can be checked to ensure corruption is avoided/minimised