network time synchronisation in java

[bossebo]

Hi everyone! I hope someone can help me with this problem.

I want to synchronize two network clients in time so that they can execute a command at an exact point in time.

* FIRST: An algorithmic approach
I have tried to solve this problem by sending packets between the two clients, but it seems to be theoretically impossible. Anyone with a solution here. I use the udp protocol for data transfer between the clients.

* SECOND: Using network time protocol (in java?)
The second approach I come up with is using some sort of network time protocol. I have no experience of this and can not find anything of employing it with javas standard packets (I don´t want to use third party packets in the first run). Anyone with some experience on this issue.

/Anders Persson (bossebo)

[Belisarius]

Depends on what you mean "exact same time". Even on a closed network there will be lag time between clients. And even NTP doesn't perfectly sync clients. Execution will probably be off by a millisecond or two.