Modified flap damping mechanism to improve inter-domain routing convergence
Computer Communications
Filter-based RFD: can we stabilize network without sacrificing reachability too much?
NETWORKING'07 Proceedings of the 6th international IFIP-TC6 conference on Ad Hoc and sensor networks, wireless networks, next generation internet
Route flap damping with assured reachability
Proceedings of the Sixth Asian Internet Engineering Conference
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Route Flap Damping is a mechanism generally used in network routing protocols. Its goal is to limit the global impact of unstable routes by temporarily suppressing routes with rapid changes over short time periods. Although route damping is a clearly defined and simple procedure at each router, its effect in a large network setting is not well understood. We show that the current damping design leads to the intended behavior only under persistent route flapping. When the number of flaps is small, the global routing dynamics deviates significantly from the expected behavior with a longer convergence delay. Previous work observed that a single route flap can falsely trigger route suppression due to path exploration. However our simulations show that this false suppression only accounts for 30% of the convergence delay after a single route flap. Our study reveals previously unknown interactions between reuse timers at different routers. Route suppression and reuse at different routers are triggered at different times and thus affect the number of updates received by other routers. In turn, this impacts other routersý damping behavior. We propose to use Root Cause Notification to eliminate both false suppression and undesirable timer interaction.