What is a packet?
In one sentence: A small numbered piece of a bigger message. Packets travel separately and are put back together at the other end.
A little more
Big messages are chopped into small numbered pieces called packets, usually up to about 1,500 bytes each. Each packet finds its own way across the network and may arrive out of order; the receiver uses the numbers to put them back together.
If one goes missing, only that piece is sent again, which is much quicker than resending the whole thing.
It's a bit like… Posting a jigsaw puzzle in separate numbered envelopes: they might arrive in any order, but the numbers tell you how it fits.
See it in action
- 6How does a message cross the world in a blink?Race an undersea cable against satellites between any two cities, see why glass threads on the sea floor carry almost all the world's data, and chop a message into packets that arrive in a jumble..7 min · interactive
- BonusWhy can a download pick up where it left off?Break a pretend file into numbered pieces, interrupt the download, and compare restart-from-zero with resume-using-byte-ranges.6 min · interactive
- BonusHow does a photo fly to the phone next to you?Send a pretend photo to the phone next to you and watch how AirDrop and Quick Share really work: a tiny Bluetooth shout to find each other, a private Wi-Fi lane with no router, and numbered pieces that fly over like paper aeroplanes and click back together like a jigsaw.8 min · interactive