Loop-Free Forwarding Table Updates with Minimal Link Overflow

The forwarding paths in an IP network may change due to a link failure, network equipment maintenance, or reconfiguration of link weights. The forwarding tables in the routers need then to be updated. These updates may cause transient loops and link overflow, if they are not performed in an appropriate order. While existing proposals achieve loop-free updates, transient link overflow is still a problem during the updating process. In this paper, we present a method that compares the initial and final forwarding paths, and obtains the updatable nodes that do not cause any transient loop or link overflow. However, this goal is not always achievable, therefore, we propose an algorithm to update the forwarding tables that will refrain the link overflows to a minimal level. The performance study on a real topology with two setups confirms that our approach achieves smaller link overflow than by using a previously proposed approach.