Timer never synchronized

timer

#1

Hello all. In the Internet Simulator, the timer seems to never be synchronized for the two partners. It seems to lose its utility. Any having this same experience? Does anyone have a solution? Thanks for taking the time.


#2

Hi aaron,

The timer actually isn’t meant to be synchronized. Many (most?) real networking devices don’t synchronize clocks, it would be too hard to sustain. In fact, if they were perfectly synchronized you’d risk losing a read or send. Instead, as long as you agree on the “tick” rate at which bits should be set or read on the wire you can ensure that the sender and receiver effectively alternate.

Here’s an example timeline that shows the sender and receiver affecting the wire at the exact same rate. Imagine that the setter’s clock is not synchronized with the reader’s clock, but both are setting or reading at the same rate.

  set: v----v----v----v----v----v----v----v
 read: --^----^----^----^----^----^----^----^

As you can see this setup ensures that every time there is a read, the wire has been set within the last interval. If you tried to perfectly synchronize the clocks and because after all, humans are setting the wire for this activity/exercise, you’d probably run into a lot of errors in which the read happened the split second before the set and things would get messed up.

Does this make sense?

–Baker
CSP Team