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Re: "ARPANet Co-Founder Predicts An Internet Crisis" (slashdot)
Paul Vixie wrote: > "Dr. Larry Roberts, co-founder of the ARPANET and inventor of packet > switching, predicts the Internet is headed for a major crisis in an article > published on the Internet Evolution web site today. Internet traffic is now > growing much more quickly than the rate at which router cost is decreasing, > Roberts says. At current growth levels, the cost of deploying Internet > capacity to handle new services like social networking, gaming, video, VOIP, > and digital entertainment will double every three years, he predicts, creating > an economic crisis. Of course, Roberts has an agenda. He's now CEO of Anagran > Inc., which makes a technology called flow-based routing that, Roberts claims, > will solve all of the world's routing problems in one go." > > http://slashdot.org/article.pl?sid=07/10/25/1643248 So I seem to recall flow cached l3 switches being rather common. ;) Over here in the firewall business we offload flows from the firewall policy enforcement engine into flow cached forwarding engines. In both cases (switch/firewall) you trade one expense (fib lookups) with another (keeping track of flow state for the purposes of forwarding). Since statefull inspection firewalls have to track flow state anyway paying the flow state tax is a built in assumption. The problem of flow cached switches was the first packet hitting the processor from each flow. Most of the flows are rather short so the processor ended up with more than it's share of the heavy lifting for the prevailing internet style traffic workloads. I suppose if one pushed flow caches down into the forwarding engines of current router asics you could reap the benefits of not performing a longest match match lookup on every packet, though mostly you just have another look aside interface and yet more memory contributing additional complexity that's poorly utilized in worse case workloads... Like I said if you're buying a firewall or a load balancer you probably get to pay this tax anyway, but the core router customer voted with their wallets a while ago, and while revisiting the issue occasionally is probably worth it I wouldn't expect flow caching to be the revolution that got everyone to swap out their gear.