Impact of Prefix-Match Changes on IP Reachability

Date Added: Nov 2009
Format: PDF

Although most studies of Internet routing treat each IP address block (Or prefix) independently, the relationship between prefixes is important because routers ultimately forward packets based on the "Longest-matching prefix." In fact, the most-specific prefix for a given destination address may change over time, as BGP routes are announced and withdrawn. Even if the most-specific route is withdrawn, routers may still be able to deliver packets to the destination using a less-specific route.