SDN Internet Router (sir)

Thu Jan 5 20:27:40 UTC 2023

Very true. 

https://www.cidr-report.org/cgi-bin/plota?file=%2fvar%2fdata%2fbgp%2fas2.0%2fbgp%2dactive%2etxt&descr=Active%20BGP%20entries%20%28FIB%29&ylabel=Active%20BGP%20entries%20%28FIB%29&with=step 

"big enough" equipment from not that long ago couldn't carry a full table today (or tomorrow). 

----- 
Mike Hammett 
Intelligent Computing Solutions 

Midwest Internet Exchange 

The Brothers WISP 

----- Original Message -----

From: "Joe Maimon" <jmaimon at jmaimon.com> 
To: "Mike Hammett" <nanog at ics-il.net>, "Tom Beecher" <beecher at beecher.cc> 
Cc: "NANOG" <nanog at nanog.org> 
Sent: Thursday, January 5, 2023 2:22:22 PM 
Subject: Re: SDN Internet Router (sir) 

Lots of 1M tcam fib limits in older gear....... 

So yeah, its the same problem, bigger numbers and still not solved in 
any sort of non-painful or expensive way. 

I think Ill explore the google path and paper on it again. 

Joe 

Mike Hammett wrote: 
> Then please bless the world with the right way. 
> 
> You acknowledge that not every router in a network needs to be fully 
> DFZ capable, but then crap on my desire to have more than a default 
> route in one. 
> 
> 
> 
> ----- 
> Mike Hammett 
> Intelligent Computing Solutions <http://www.ics-il.com/> 
> <https://www.facebook.com/ICSIL><https://plus.google.com/+IntelligentComputingSolutionsDeKalb><https://www.linkedin.com/company/intelligent-computing-solutions><https://twitter.com/ICSIL> 
> Midwest Internet Exchange <http://www.midwest-ix.com/> 
> <https://www.facebook.com/mdwestix><https://www.linkedin.com/company/midwest-internet-exchange><https://twitter.com/mdwestix> 
> The Brothers WISP <http://www.thebrotherswisp.com/> 
> <https://www.facebook.com/thebrotherswisp><https://www.youtube.com/channel/UCXSdfxQv7SpoRQYNyLwntZg> 
> ------------------------------------------------------------------------ 
> *From: *"Tom Beecher" <beecher at beecher.cc> 
> *To: *"Mike Hammett" <nanog at ics-il.net> 
> *Cc: *"Mel Beckman" <mel at beckman.org>, "NANOG" <nanog at nanog.org> 
> *Sent: *Thursday, January 5, 2023 9:55:38 AM 
> *Subject: *Re: SDN Internet Router (sir) 
> 
> "The right tool for the job" gets into a religious argument in 
> assuming that one's way to do the job is the only reasonable way 
> to do the job 
> 
> 
> I disagree that it's religious. I completely agree there are locations 
> in networks that having full DFZ capable routers doesn't make 
> technical or economic sense. But there have long been different 
> products for those different use cases. 
> 
> To perhaps explain my viewpoint better,(and perhaps I didn't properly 
> comprehend the problem you're aiming to solve) : 
> 
> If you are trying to use SDN stuff to shuffle routes on and off a box 
> because you have the wrong sized routers in place, then I would argue 
> you're doing it wrong. 
> 
> If you are trying to use SDN stuff to (as Christopher mentioned) make 
> decisions that are not strictly LPM, and the equipment you have cannot 
> do that, then that's different and entirely reasonable. 
> 
> If the second use case is more of what you were asking, then I 
> apologize for misunderstanding. 
> 
> 
> On Thu, Jan 5, 2023 at 9:57 AM Mike Hammett <nanog at ics-il.net 
> <mailto:nanog at ics-il.net>> wrote: 
> 
> "The right tool for the job" gets into a religious argument in 
> assuming that one's way to do the job is the only reasonable way 
> to do the job. 
> 
> Large networks historically have a very poor (IMO) model of 
> gigantic iron in a few locations, which results in sub-optimal 
> routing for the rest of their network between those large POPs. 
> I've heard time and time again that someone buying service from a 
> major network in say New Orleans has a first hop of Dallas or 
> Atlanta. I agree that full-route capable routers need to be in the 
> large, central locations, but it isn't cost effective to have them 
> at every POP, especially if you're a last-mile provider. 
> 
> I'd go into more examples of where it doesn't make sense to have 
> full-route routers everywhere, but I'm afraid that the Internet 
> would then focus on the examples instead of the core idea of 
> intelligently putting routes into the FIBs of low-FIB routers 
> throughout my network. 
> 
> 
> 
> ----- 
> Mike Hammett 
> Intelligent Computing Solutions <http://www.ics-il.com/> 
> <https://www.facebook.com/ICSIL><https://plus.google.com/+IntelligentComputingSolutionsDeKalb><https://www.linkedin.com/company/intelligent-computing-solutions><https://twitter.com/ICSIL> 
> Midwest Internet Exchange <http://www.midwest-ix.com/> 
> <https://www.facebook.com/mdwestix><https://www.linkedin.com/company/midwest-internet-exchange><https://twitter.com/mdwestix> 
> The Brothers WISP <http://www.thebrotherswisp.com/> 
> <https://www.facebook.com/thebrotherswisp><https://www.youtube.com/channel/UCXSdfxQv7SpoRQYNyLwntZg> 
> ------------------------------------------------------------------------ 
> *From: *"Tom Beecher" <beecher at beecher.cc <mailto:beecher at beecher.cc>> 
> *To: *"Mike Hammett" <nanog at ics-il.net <mailto:nanog at ics-il.net>> 
> *Cc: *"Mel Beckman" <mel at beckman.org <mailto:mel at beckman.org>>, 
> "NANOG" <nanog at nanog.org <mailto:nanog at nanog.org>> 
> *Sent: *Wednesday, January 4, 2023 7:36:58 AM 
> *Subject: *Re: SDN Internet Router (sir) 
> 
> Disagree that it’s a line in the sand. It’s use the right tool for 
> the job. 
> 
> If a device is low FIB, it’s that way for a reason. There are 
> plenty of ways to massage that with policy and software, depending 
> on capabilities , but at the end of the day, trying to sort 10 
> pounds of shit to store in a 5 pound bag is eventually going to 
> end up the same way. 
> 
> On Tue, Jan 3, 2023 at 13:18 Mike Hammett <nanog at ics-il.net 
> <mailto:nanog at ics-il.net>> wrote: 
> 
> There are likely more networks with 10 gigabit or less total 
> external capacity than there are with more. 
> 
> Creating imaginary lines in the sand doesn't really help anyone. 
> 
> 
> 
> 
> ----- 
> Mike Hammett 
> Intelligent Computing Solutions <http://www.ics-il.com/> 
> <https://www.facebook.com/ICSIL><https://plus.google.com/+IntelligentComputingSolutionsDeKalb><https://www.linkedin.com/company/intelligent-computing-solutions><https://twitter.com/ICSIL> 
> Midwest Internet Exchange <http://www.midwest-ix.com/> 
> <https://www.facebook.com/mdwestix><https://www.linkedin.com/company/midwest-internet-exchange><https://twitter.com/mdwestix> 
> The Brothers WISP <http://www.thebrotherswisp.com/> 
> <https://www.facebook.com/thebrotherswisp><https://www.youtube.com/channel/UCXSdfxQv7SpoRQYNyLwntZg> 
> ------------------------------------------------------------------------ 
> *From: *"Mel Beckman" <mel at beckman.org <mailto:mel at beckman.org>> 
> *To: *"Mike Hammett" <nanog at ics-il.net <mailto:nanog at ics-il.net>> 
> *Cc: *"NANOG" <nanog at nanog.org <mailto:nanog at nanog.org>> 
> *Sent: *Tuesday, January 3, 2023 10:57:34 AM 
> *Subject: *Re: SDN Internet Router (sir) 
> 
> It’s not a problem, due to cheap, plentiful high-speed memory 
> and rapid prefix search silicon in backbone routers. The 
> entire Internet routing table consumes at most a few gigabytes 
> when fully structured (and only a few hundred Mbytes stored 
> flat). That’s less memory than your average laptop sports. 
> 
> 
> Even in the worst case scenario, where every network decides 
> to announce only its most specific prefixes, the BGP backbone 
> would temporarily enter an oscillating state that generates a 
> large number of routing updates into the inter-domain routing 
> space. In this case, BGP route damping will quickly suppress 
> the crazies while the backbone stabilizes. 
> 
> 
> Small routers should not be taking full tables, since there is 
> no point to them being in the default free zone. For large 
> routers, neither memory nor CPU speed are an issue. High-speed 
> routers operating in the default-free zone have a critical 
> path in the forwarding decision for each packet: it needs to 
> take less than the inter-packet arrival time for minimum-sized 
> IP packets. 
> 
> 
> This is easy to achieve with today’s hardware. A router line 
> card with an aggregate line rate across all of its 
> point-to-point interfaces of 10Tbps (readily available in 
> today’s gear) can process packets with just a handful of 
> cycles in the FIB Ternary Content Addressable Memory (TCAM) 
> using ASIC-assisted lookups. TCAM is the most expensive 
> component you’re paying for in such a router. It’s not cheap, 
> but backbone routers don’t need to be cheap. They just need to 
> not be memory-constrained. 
> 
> 
> -mel via cell 
> 
> On Jan 3, 2023, at 7:47 AM, Mike Hammett <nanog at ics-il.net 
> <mailto:nanog at ics-il.net>> wrote: 
> 
> 
> https://github.com/dbarrosop/sir 
> 
> I came across this over the weekend. Given that the 
> project was abandoned six years ago, are there any other 
> efforts with a similar goal (more intelligently placing 
> routes into FIBs of low-FIB capacity devices? 
> 
> 
> 
> ----- 
> Mike Hammett 
> Intelligent Computing Solutions <http://www.ics-il.com/> 
> <https://www.facebook.com/ICSIL><https://plus.google.com/+IntelligentComputingSolutionsDeKalb><https://www.linkedin.com/company/intelligent-computing-solutions><https://twitter.com/ICSIL> 
> Midwest Internet Exchange <http://www.midwest-ix.com/> 
> <https://www.facebook.com/mdwestix><https://www.linkedin.com/company/midwest-internet-exchange><https://twitter.com/mdwestix> 
> The Brothers WISP <http://www.thebrotherswisp.com/> 
> <https://www.facebook.com/thebrotherswisp><https://www.youtube.com/channel/UCXSdfxQv7SpoRQYNyLwntZg> 
> 
> 
> 
> 

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