FRTR: A Scalable Mechanism to Restore Routing Table Consistency

This paper presents a scalable mechanism, Fast Routing Table Recovery (FRTR), for detecting and correcting route inconsistencies between neighboring BGP routers. A periodic update approach, used by most routing protocols, is considered infeasible due to the large size of today’s global routing table. In FRTR neighboring routers periodically exchange Bloom filter digests of the routing state to detect any potential routing inconsistency. The digests can also facilitate efficient recovery after a BGP session reset. FRTR achieves a low bandwidth overhead by using small digests, and achieves strong consistency by “salting” the digests with random seeds to overcome Bloom filter’s false-positive drawback. Our analysis and simulation results show that, with one round of message exchange, FRTR can detect and recover over 91% of random errors that the current BGP would have missed and the overhead can be as low as 1.3% of a full routing table exchange. With salted digests FRTR can detect all the errors with a probability close to 100% after a few rounds of exchanges.