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Re: Do ATM-based Exchange Points make sense anymore?
Paul Vixie wrote: > Adding complexity to a system increases its cost but not nec'ily its value. > Consider the question: how often do you expect endpoint liveness to matter? The issue I'm trying to address is to figure out how to extend the robustness that can be achieved with tuned IGP's with subsecond convergence across an exchange point without suffering a one to five minute delay blackholing packets. Liveness is an issue when a box either loses coherency between software and hardware state on an interface or decides to reload all or part of the system without minding to reset the BGP TCP sessions before going away. I'd be happy to hear solutions that are in use and commonplace for this problem. Mostly I've seen "it's the other guys problem" as an answer and solution being migrating all connectivity to one ISP. > > If the connection fabric between your routers has an MTBF best measured in > hours or days, then you've got bigger problems than you'll solve with LMI. > > If on the other hand the MTBF is best measured in months or years, then when > it does fail the failure is likely to be *in* the extra complexity you added. As far as I understand, this "complexity" just got added with Neighbor Discovery on IPv6. Which would solve this problem when properly propagated up the stack from ND to TCP and tweaking the ND timers down. No need to touch the BGP timers. Pete