On 2011-07-17 19.24, Bob Armstrong wrote: Bob, endnodes in different areas can only talk to each other if there's no router present. So your scheme only works if all of us shut down all our L1 and L2 routers. We don't have to shut down all the routers on HECnet, right? Just shutting down the router for my area (or the area of anyone else who cares about the issue) would be sufficient. Yes... As long as you don't want to talk to anything that is not on the same segment. But since there are machines further away, this sounds like a sad limitation. Once an endnode sees a router in its area ... Exactly... If there are no routers in the end node's area, then communications is direct. Routers for other areas are moot. No. Communication are only direct to destinations which are on the same segment. The endnode will have no idea what to do if the destination is not on the same segment, and there is no router. And so those packets will be tossed. Johnny