The "Byzantine Agreement Problem" is _not_ solved in theory. The last time I surveyed the literature, it was still widely conjectured to be theoretically intractable. It has direct implications on networks and networked systems; however, often some of the constraints of the original problem can, with effort, be violated---which makes practical systems more feasible. These violations usually take the form of a second, more reliable, band of communication. Scott Collins | "That's not fair!" -- Sarah | "You say that so often. I wonder what your basis 408.862.0540 | for comparison is." -- Goblin King ................|.................................................... BUSINESS. fax:974.6094 R254(IL5-2N) collins@newton.apple.com Apple Computer, Inc. 5 Infinite Loop, MS 305-2D Cupertino, CA 95014 ..................................................................... PERSONAL. 408.257.1746 1024:669687 catalyst@netcom.com