In systems using shortest-path routing tables, a single link failure is enough to interrupt the message transmission by disconnecting one or more shortest path spanning trees. The on-line recomputation of an alternative path or of the entire new shortest path trees, rebuilding the routing tables accordingly, is rather expensive and causes long delays in the message’s transmission [5, 10]. Hopefully, some of these costs will be reduced if the serial algorithms for dynamic graphs (e.g., those of [1]) could be somehow employed; to date, the difficulties of finding an e.cient distributed implementation have not been overcome (e.g., see [9]).