[MUD-Dev2] [TECH] Client time-server time sync

[Jeffrey Kesselman]

On 4/23/07, Roger D Vargas <luo_hei at yahoo.es> wrote:
> Yesterday I was talking to a friend and he insisted in the need of
> having perfectly synchronized server and client time, among other
> things, to calculate movements. I had thought that such thing was not
> needed, as I just need the notification of move start and figure out
> every certain time the location of player until a move stop notification
> arrives. Am I wrong about this?

Such a thing is impossible.

The issue is that he used the word "perfectly."  You cannot synchronize
remote systems perfectly.  This is a well proved thing in the academic
world of distributed computing.

You can get systems *approximately* synchronized with protocols like ntp
that attempt to detect and correct drift, but some drift is a matter of
life.

Having said that you *may* be able to get a synch good enough for your
particular game design.  Thats a matter of design.,

As to whether its "absolutely essential", no it isn't.  Some latency
hiding techniques make use of timestamps, such as classic "dead
reckoning", others do not. It really comes down to the limits and
assumptions you design your game with