"ARPANet Co-Founder Predicts An Internet Crisis" (slashdot)
"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
On 10/25/07, Paul Vixie <paul@vix.com> wrote:
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."
Anyone have any experience with these Anagran flow routers? Are they that much of a departure from traditional routing that it makes a big difference? I haven't done a lot of research into flow-based routing at this point, but it sounds like this would be similar to the MPLS approach, no? How about cost per port versus traditional routers from Cisco or Juniper? It seems that he cites cost as the main point of contention, so are these Anagran routers truly less expensive? -- Jason 'XenoPhage' Frisvold XenoPhage0@gmail.com http://blog.godshell.com
When we start migrating to IPv6, wouldn't state-aware forwarding be required for a good part of the traffic that is being translated from customer IPv6 to a legacy IPv4 ? I'm a personal fan of topology-based forwarding, but this is limited to the address space of the topology we currently use, which is running out of space in a few years (few meaning whatever version of the IPv4 RIRs deadline you believe in). Rubens On 10/25/07, Jason Frisvold <xenophage0@gmail.com> wrote:
On 10/25/07, Paul Vixie <paul@vix.com> wrote:
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."
Anyone have any experience with these Anagran flow routers? Are they that much of a departure from traditional routing that it makes a big difference? I haven't done a lot of research into flow-based routing at this point, but it sounds like this would be similar to the MPLS approach, no?
How about cost per port versus traditional routers from Cisco or Juniper? It seems that he cites cost as the main point of contention, so are these Anagran routers truly less expensive?
-- Jason 'XenoPhage' Frisvold XenoPhage0@gmail.com http://blog.godshell.com
On 25 Oct 2007 at 17:02 -0400, Jason Frisvold allegedly wrote:
Anyone have any experience with these Anagran flow routers? Are they that much of a departure from traditional routing that it makes a big difference?
There's no difference in routing per se. Rather it's in-band signaling of QoS parameters to provide feedback to queue management.
I haven't done a lot of research into flow-based routing at this point, but it sounds like this would be similar to the MPLS approach, no?
There is no setup phase. Signaling is in-band and periodic. The theory is that every once in a while a control packets is sent, with the same src/dst as the regular data packets. Whatever paths the packets take, the control packets will take the same paths.
On Thu, Oct 25, 2007 at 05:36:11PM -0400, Scott Brim wrote:
On 25 Oct 2007 at 17:02 -0400, Jason Frisvold allegedly wrote:
Anyone have any experience with these Anagran flow routers? Are they that much of a departure from traditional routing that it makes a big difference?
There's no difference in routing per se. Rather it's in-band signaling of QoS parameters to provide feedback to queue management.
I read over the vendor's site when that article was sent, and I'll be honest, a lot of what they are trumpeting are steps backwards in router performance. While the site is pretty light on the details, Anagram's "Fast Flow Routing Architecture" sounds very similar to dated multilayer switching approaches. CEF-like adjacency certainly provides higher routing throughput with less overhead. So if it's a win, it must be a win because the cost of going back to a flow-caching is offset by a gain in better QoS. Their QoS details are a bit sketchy, but this would worry me: BTC basically '"watches" every flow. By constantly comparing each flow's behavior over time against a simple set of operator-defined rules per flow class, BTC can identify "suspect" flows that by virtue of their duration, byte count, source/destination, or other criteria, require some form of corrective or policing action. So now there's a "flow table" that in the forwarding plane. What happens when the flow table overflows? How does the router decide when to age-out a flow? I have yet to see a flow-centric filtering device save the network when it's flow/session table is what's under attack. -- Ross Vandegrift ross@kallisti.us "The good Christian should beware of mathematicians, and all those who make empty prophecies. The danger already exists that the mathematicians have made a covenant with the devil to darken the spirit and to confine man in the bonds of Hell." --St. Augustine, De Genesi ad Litteram, Book II, xviii, 37
On Thu, 25 Oct 2007, 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."
I don't know, this is mildly offtopic (aka, not very operational) but the article made me giggle a few times. a) It resembles too much of Bob Metcalfe predicting the death of the Internet. We all remember how that went (wasn't there NANOG tshirt with Bob eating his hat?) b) In the words of Randy Bush, "We tried this 10 years ago, and it didn't work then". Everyone was doing flow-based routing back in '90-95 (cat6k sup1, gsr e0, first riverstoned devices, foundry ironcore, etc). Then, everyone figured out that it does not scale (tm Vijay Gill) and went to tcam-based architectures (for hardware platforms) or cef-like based architectures for software platforms. In either case, performance doesn't depend on flows/second, but only packets/second. Huge problem with flow-based routing is susceptibility to ddos (or abnormal traffic patterns). It doesn't matter that your device can route 1mpps of "normal" traffic if it croaks under 10kpps of ddos (or codered/nimda/etc). -alex [not mlc anything] [mlc]
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."
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.
participants (7)
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Alex Pilosov -
Jason Frisvold -
Joel Jaeggli -
Paul Vixie -
Ross Vandegrift -
Rubens Kuhl Jr. -
Scott Brim