Reactive Routing Of the failures that reactive routing could mask, only half coincided with BGP messages. Multihoming: a near-necessary (but not sufficient) condition for always masking failures 25 paths: RON always masked failures All of these paths had at least one multihomed end 18 were multihomed at both ends 136 paths: RON never masked failures 106 paths had at least one multihomed end 35 were multihomed at both ends