Free The transport layer lessonsThe transport layer · Stage 0 · Between processes · Step 1
Ports, sockets and UDP
See how one machine's many programs share one IP address, what UDP adds to IP, and when that is enough. About 13 minutes.
What does a destination port number identify?
- AWhich program (socket) on the destination machine should receive the data
- BWhich machine on the network
- CWhich route the packet takes
Show the answer
Which program (socket) on the destination machine should receive the data. The IP address chose the machine; the port chooses the application on it.
4 questions on this idea
Short questions that apply the idea to new cases: trace it, work out a number, put steps in order. A wrong answer explains itself.
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