Packet switching Flashcards
Packet Switching
Method of data transmission where the data is broken into multiple packets. Packets are then sent independently from start to end and reassembled at the receiver’s computer.
The benefits of packet switching are:
» there is no need to tie up a single communication line
» it is possible to overcome failed, busy or faulty lines by simply re-routing
packets
» it is relatively easy to expand package usage
» a high data transmission rate is possible.
The drawbacks of packet switching include:
» packets can be lost and need to be re-sent
» the method is more prone to errors with real-time streaming (for example, a
live sporting event being transmitted over the internet)
» there is a delay at the destination whilst the packets are being re-ordered.
What issue arises when packets keep bouncing between routers?
Packets can get lost, clogging the system as they continuously bounce from router to router without reaching their destination.
What happens if too many packets are lost in a network?
The network can grind to a halt as the number of lost packets builds up, overwhelming the system.
What is the purpose of hopping in packet transmission?
Hopping ensures packets don’t endlessly bounce between routers by assigning each packet a hop number that decreases as it moves from router to router.
How is the hop number used to prevent packet loss?
Each packet starts with a maximum hop number, and this number decreases by 1 every time it passes through a router. If the hop number reaches zero before the packet reaches its destination, the packet is deleted.
What happens to packets when their hop number reaches zero?
When the hop number reaches zero, the packet is deleted by the router it reaches, preventing it from continuing to bounce around the network.
How does the receiving computer handle missing packets due to hopping?
The receiving computer flags the missing packets and requests that the sending computer re-send them.
