Virtually eliminating router bugs

Software bugs in routers lead to network outages, security vulnerabilities, and other unexpected behavior. Rather than simply crashing the router, bugs can violate protocol se-mantics, rendering traditional failure detection and recovery techniques ineffective. Handling router bugs is an increas-ingly important problem as new applications demand higher availability, and networks become better at dealing with tra-ditional failures. In this paper, we tailor software and data diversity (SDD) to the unique properties of routing proto-cols, so as to avoid buggy behavior at run time. Our bug-tolerant router executes multiple diverse instances of routing software, and uses voting to determine the output to publish to the forwarding table, or to advertise to neighbors. We de-sign and implement a router hypervisor that makes this par-allelism transparent to other routers, handles fault detection and booting of new router instances, and performs voting in the presence of routing-protocol dynamics, without needing to modify software of the diverse instances. Experiments with BGP message traces and open-source software running on our Linux-based router hypervisor demonstrate that our solution scales to large networks and efficiently masks buggy behavior