3 ms·
That's right, although keep in mind that 'start' may not be 'when the packet was sent'. For example, when you measure the difference between two paths (e.g. A-
by Strilanc 14y ago
That's right, although keep in mind that 'start' may not be 'when the packet was sent'.
For example, when you measure the difference between two paths (e.g. A->D vs A->B->C->D), the 'start' is one arrival time and the 'end' is the other arrival time.
There's actually a few simple consequences I didn't mention in the post. Maybe in the future I'll try to include more.
For example, I mention that it's a good thing we can model games as 'all players seeing the same time'. This is probably how most players actually model the game in their head! If it didn't work, online games would be a lot harder to understand, differ more from reality, and generally be less fun!
- Strilanc 14y agoCorrection, what's important is that the skews from each clock are cancelled. Doing both measurements on one clock is a special case. For example, if you measure the skewed time for A->D as (arrival time on D) - (send time on A) and then later measure the skewed time for A->B->C->D in the same way, you can get the non-skewed path difference by subtracting the two skewed times.
- niggler 14y agoThat's actually incorrect because of drift (if D's clock is faster than A's clock, if you don't correct for drift the measurements can't be reliably compared). You'd have to correct for drift for every step (A->B, B->C, C->D) before you start.
- Strilanc 14y agoRight, I was assuming negligible clock drift between when each measurement was performed.