What about loops in the network? If someone "beyond" PSUVM sends mail to CEARN (for example) it is easily possible that the file would go through the BITNET-EARNET link on the way to Europe but that a reply would come back through DEARN-GWUVM instead. If the networking software were expecting all files from a node to come a certain direction, all such loops would have to be eliminated and routing would have to stay static. If security is the primary concern, that is fine. But for customers with closed, secure circuits, the loss of flexibility might be bad news. Playing the devil's advocate? Nick