How to know when one device doesn't work...?

Hi,

I have one application, where 3 devices work together. I have a Heart-beat in one of them(*) to know when someone has stopped to work.I have the problem here. I have done the Heart beat with connections UDP. I'm all the time sending messages UDP to *, and * receiving, but then , when someone fails, * wait indefinitely .May be it's better to do Multicast? but I don't know how to control it, bacause of, maybe one device send his message UDP to late. Anyone knows how to do it?Thanks

[505 byte] By [berlinerwurma] at [2007-11-27 11:14:03]