Computers on the internet send data in packets. Messages can be sent using either Circuit Switching or Packet switching
When transferring data across a network (e.g. the internet), data is split into small bundles called 'packets'.
The packets are a standard size and larger messages simply have more packets.
Each packet has;
a label, ( to id the packet)
sequence number, (to know where in the order it belongs)
destination address (where it is being sent
a checksum (to ensure no errors occurred during transmission)
Circuit switching:
A path between 2 machines is established at the start.
all the data packets are sent in order
- This ties up the networks resources untill message is finished
- Inefficient use of resources
- Easy to intercept message
+ They arrive in the right order and do not need sorting
Packet switching:
The packets of data are sent at the most convenient route at the time of transmission
Each packet tries to find the most efficient route (various routes)
When a machine receives a packet it checks label to see if correct destination, if not it passes it on.
- Need sorting into order at destination, before the message can be read
+ More difficult to intercept messages
+ More efficient use of Network resources