Latency - Intro to Computer Science
Udacity
https://www.youtube.com/watch?v=6_1akTCAnt4

Transkript (automatisch erstellt)

0:00 I want to talk about the two main ways to measure a network. Those are called Latency and Bandwidth.
0:08 What they mean is very different. They're often confused. Often people say bandwidth when they mean latency, or
0:14 say latency when they mean bandwidth. They're quite different things. So let me explain what they are. So
0:20 latency is the time that it takes for a message to get from the source to the destination.
0:25 And that's for the start of the message. So, we can measure latency by timing when you start sending to the time
0:32 that the receiver starts receiving. So this is the unit of time. It will be measured in something like seconds. For a fast
0:41 network today, it's more often measured in milliseconds and there are 1000 milliseconds in one second.
0:50 So now, you understand about latency. And when I go back to the Greek signaling network. So, suppose now
0:57 that Zeus, who is all powerful, wanted to send a message from Rhodes to Sparta. And he thought that the
1:03 latency of the smoke signal network as it was currently set up was too high, that it takes too
1:08 long for the message that he sends starting from Rhodes to reach Sparta. So the question is, how could Zeus,
1:15 and remember that in ancient Greece, Zeus was all powerful, reduce the latency between Rhodes and Sparta. So
1:23 here are the choices. It makes the signalling nodes further apart. So instead of going from Rhodes to
1:29 Naxos to Millios to Sparta, maybe it would have to go one hop. There would be a new
1:35 island in the middle here, and it could go from Rhodes to the new island and then to Sparta.
1:40 He could threaten the soldiers at all the signalling points and scare them into working harder, so they start the fires more quickly,
1:47 when they need to send a message. He could find a way to make it so instead of just sending one color smoke, you
1:52 could send different colors smoke. That would mean that with the same amount of smoke, you could send more different messages. Or he could
1:59 increase the speed of light. That would mean that the the soldiers at each signaling point would see the previous smoke signal more quickly
2:06 than they do now.