RIPPLE: Loop-Free Multi-Path Routing with Minimum Blocking during Convergence

The Routing Information Protocol with Probing for Looplessness and Efficiency (RIPPLE) is introduced for loop-free multi-path routing. Each router maintains the distance and the hop-count (called the hop-count reference) along its preferred path to each destination. Routers are allowed to select neighbors as next hops to destinations as long as they satisfy an ordering condition based on the values of hop-count references. If needed, routers use probes to find valid routes provided by routers with the same hop-count references as those stated in probes. RIPPLE is shown to be loop-free, which allows it to converge to shortest paths within a finite time even when nodes fail or the network partitions. RIPPLE is also shown to be near-optimal in terms of the time routers take to attain new loop-free routes to destinations.