SDN Internet Router (sir)

Fri Jan 6 15:51:43 UTC 2023

Gotcha.

Setup a Quagga/Bird box. Do your top talker analysis , use that box to
inject the routes you deem important with communities.  On your routers ,
create policy structure to only take a default plus those communities.

Obviously lots of devils in the details of the implementation , but
something like that is all you need to do.

On Fri, Jan 6, 2023 at 10:29 Mike Hammett <nanog at ics-il.net> wrote:

> Maybe?
>
> I don't need any additional performance tests, though. Just watching which
> prefixes are the top talkers and leaving the rest to default.
>
> I'm not looking at this to do what a BGP optimizier would do and find the
> best tested path to the top talkers and then massage BGP to get it routed
> that way. Determine the top talkers, then let BGP do its thing for those
> top talkers.
>
> I don't want to manually say X traffic from Y POP manually goes here, but
> I don't want to just leave it to default routing either. Something in the
> middle.
>
>
>
> -----
> 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: *Friday, January 6, 2023 9:16:19 AM
>
> *Subject: *Re: SDN Internet Router (sir)
>
> Thanks for this example.
>
> It sounds like you are describing egress peer engineering, but kinda in
> reverse.
>
> In 'traditional' EPE, the routers have all the routes, and you are using
> the external controller to perform the performance tests that matter to
> you, and signal the network where to take the traffic based on those tests.
>
> It seems like you want to do the same thing , but instead of having the
> controller signal the network where to carry bits, you want the controller
> to signal the networks what routes are present, and direct the bits that
> way.
>
> Do I have this right?
>
> On Thu, Jan 5, 2023 at 4:12 PM Mike Hammett <nanog at ics-il.net> wrote:
>
>> I hesitated to get too specific in examples because someone is going to
>> drag the conversation into the weeds.
>>
>> Let's take the the Dallas - New Orleans - Atlanta example where I have a
>> connection from New Orleans to Dallas and a connection from New Orleans to
>> Atlanta.
>>
>> Let's say I peer with Netflix in both markets. Netflix chooses to serve
>> me out of Atlanta, for whatever reason. Say my default route sends my
>> traffic to Dallas. That's not where Netflix wanted it, so now I have to go
>> from Dallas to Atlanta, whether that's my circuit or across the public
>> Internet. Potentially, it's on MPLS and it rides back through the New
>> Orleans router to get back to Atlanta. That's a long trip when I already
>> had a better path, the less-than-full-fib router just didn't know about it.
>> Given that Netflix is a sizable amount of traffic in an eyeball ISP, that's
>> a lot of traffic to be going the wrong way. If the website for Viktor's
>> Arctic Plunge in Siberia was hosted in Atlanta, I wouldn't give two craps
>> that the traffic went the wrong way because A), I'll probably never go
>> there and B) when someone does, it won't be meaningfully enough traffic to
>> accommodate.
>>
>> Someone's going to tell me to put a full-table router in New Orleans.
>> Maybe I should. Okay, so maybe I have a POP in Ashford, Alabama. It has
>> transport to New Orleans and Atlanta. There aren't enough grains of sugar
>> in Ashford, Alabama to justify a current-generation, full table router. Now
>> I'm even closer to Atlanta, but default may point to New Orleans.
>>
>>
>>
>> -----
>> 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>
>> *To: *"Mike Hammett" <nanog at ics-il.net>
>> *Cc: *"Joe Maimon" <jmaimon at jmaimon.com>, "NANOG" <nanog at nanog.org>
>> *Sent: *Thursday, January 5, 2023 2:54:27 PM
>> *Subject: *Re: SDN Internet Router (sir)
>>
>> Mike,
>>
>> I’m not sure I understand what you mean by “suboptimal“ routing. Even
>> though the Internet uses AS path length for routing,  many of those path
>> lengths are bogus, and don’t really represent any kind of path performance
>> value. For example, a single AS might hide many hops in an MPLS network as
>> a single hop, obscuring asymmetric routing and other uglies. Prepending
>> also occurs when destinations are trying to enforce their own engineering
>>  policies, which often conflict with yours or mine.
>>
>> So what do you mean by “suboptimal“? Are you thinking that the “best”
>> path in BGP tables actually meant you were getting a performance benefit?
>> Because that’s definitely not the case in today’s Internet. Were were you
>> thinking that you would be going along less congested paths? That’s really
>> at the mercy of the traffic engineering of backbone providers over which we
>> have no control.
>>
>> I generally populate local router FIBs to merel choose an exit point for
>> purposes of load balancing, and nothing more.
>>
>>  -mel
>>
>> On Jan 5, 2023, at 12:38 PM, Mike Hammett <nanog at ics-il.net> wrote:
>>
>> 
>> I guess I wasn't around for those days.
>>
>> As far as running out, again, assuming the tooling works correctly, I'd
>> think to target fewer routes than you could hold. Maybe 1k routes is all
>> one would need to get a significant percent of the traffic. A lot of room
>> to mess up if you can hold 100k, 500k routes.
>>
>>
>>
>> -----
>> 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: *"Joe Maimon" <jmaimon at jmaimon.com>
>> *To: *"Mike Hammett" <nanog at ics-il.net>, "Christopher Morrow" <
>> morrowc.lists at gmail.com>
>> *Cc: *"NANOG" <nanog at nanog.org>
>> *Sent: *Thursday, January 5, 2023 2:30:40 PM
>> *Subject: *Re: SDN Internet Router (sir)
>>
>>
>>
>> Mike Hammett wrote:
>> > I'm not concerned with which technology or buzzword gets the job done,
>> > only that the job is done.
>> >
>> >
>> >
>> > Looking briefly at the couple of things out there, they're evaluating
>> > the top X prefixes in terms of traffic reported by s-flow, where X is
>> > the number I define, and those get pushed into the FIB. One
>> > recalculates every hour, one does so more quickly. How much is
>> > appropriate? I'm not sure. I can't imagine it would *NEED* to be done
>> > all of that often, given the traffic/prefix density an eyeball network
>> > will have. Default routes carry the rest. Default routes could be
>> > handled outside of this process, such that if this process fails, you
>> > just get some sub-optimal routing until repaired. Maybe it doesn't
>> > filter properly and sends a bunch of routes. Then just have a prefix
>> > limit set on the box. Maybe it sends the wrong prefixes. No harm, no
>> > foul. If you're routing sub-optimally internally, when it does hit a
>> > real router with a full FIB, it gets handled appropriately.
>>
>> Unless it loops.
>>
>> The rest sounds nice. But flow caching got a bad rap back in the early
>> worm days. But thats because the situation was a little worse back then.
>> Cache the wrong routes or run out of cache, router dies. So long as
>> thats not the case automating optimization is an extremely valuable goal.
>>
>> >
>> >
>> > I would just be looking for solutions that influence what's in the FIB
>> > and let the rest of the router work as the rest of the router would.
>>
>> The problem comes when the router wont work at all without the FIB
>> routes, like in the olden days.
>> >
>> >
>> >
>> > -----
>> > 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: *"Christopher Morrow" <morrowc.lists at gmail.com>
>> > *To: *"Mike Hammett" <nanog at ics-il.net>
>> > *Cc: *"Tom Beecher" <beecher at beecher.cc>, "NANOG" <nanog at nanog.org>
>> > *Sent: *Thursday, January 5, 2023 12:27:08 PM
>> > *Subject: *Re: SDN Internet Router (sir)
>> >
>> >
>> >
>> > On Thu, Jan 5, 2023 at 11:18 AM Mike Hammett <nanog at ics-il.net
>> > <mailto:nanog at ics-il.net>> wrote:
>> >
>> >     Initially, my thought was to use community filtering to push just
>> >     IXes, customers, and defaults throughout the network, but that's
>> >     obviously still sub-optimal.
>> >
>> >     I'd be surprised if a last mile network had a ton of traffic going
>> >     to any more than a few hundred prefixes.
>> >
>> >
>> > I think in a low-fib box at the edge of your network your choices are:
>> >   "the easy choice, get default, follow that"
>> >
>> >   "send some limited set of prefixes to the device, and default, so
>> > you MAY choose better for the initial hop away"
>> >
>> > you certainly can do the second with communities, or route-filters
>> > (prefix-list) on the senders, or....
>> > you can choose what prefixes make the cut (get the community(ies))
>> > based on traffic volumes or expected destination locality:
>> >    "do not go east to go west!"
>> >
>> > these things will introduce toil and SOME suboptimal routing in some
>> > instances... perhaps it's better than per flow choosing left/right
>> > though and the support calls related to that choice.
>> >
>> > In your NOLA / DFW / ATL example it's totally possible that the
>> > networks in question do something like:
>> >   "low fib box in tier-2 city (NOLA), dfz capable/core devices in
>> > tier-1 city (DFW/ATL), and send default from left/right to NOLA"
>> >
>> > Could they send more prefixes than default? sure... do they want to
>> > deal with the toil that induces? (probably not says your example).
>> >
>> > SDN isn't really an answer to this, though.. I don't think. Unless you
>> > envision that to lower the toil ?
>> >
>>
>>
>>
>>
>
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