[Rpm] Almost had a dialog going with juniper...

rjmcmahon rjmcmahon at rjmcmahon.com
Sun Feb 19 18:52:08 EST 2023


Cisco's first acquisition was Crescendo. They started with twisted pair 
and moved to Cat5. At the time, the claim was nobody would rewire 
corporate offices. But they did and those engineers always had an AC 
power plug nearby so they never really designed for power/bit over 
distance.

Broadcom purchased Epigram. They started with twisted pair and moved to 
wireless (CMOS radios.) The engineers found that people really don't 
want to be tethered to wall jacks. So they had to consider power at all 
aspects of design.

AP engineers have been a bit of a Frankenstein. They have power per AC 
wall jacks so the blast energy everywhere to sell sq ft. The enterprise 
AP guys do silly things like PoE.

Better is to add CMOS radios everywhere and decrease power, 
inter-connected by fiber which is the end game in waveguides. Even the 
data centers are now limited to 4-meter cables when using copper and the 
energy consumption is through the roof.

Bob
> On Sun, Feb 19, 2023 at 3:37 PM rjmcmahon <rjmcmahon at rjmcmahon.com> 
> wrote:
>> 
>> A bit off topic, but the AP/client power asymmetry is another design
>> flaw similar to bloat.
> 
> It makes no sense to broadcast at a watt when the device is nearby. I
> think this is a huge, and largely unexplored problem. We tried to
> tackle it in the minstrel-blues project but didn't get far enough, and
> the rate controllers became too proprietary to continue. Some details
> here:
> 
> https://github.com/thuehn/Minstrel-Blues
> 
>> 
>> Not sure why nobody is talking about that.
> 
> Understanding of the inverse square law is rare. The work we did at
> google fiber, clearly showed the chromecast stick overdriving nearby
> APs.
> 
> https://apenwarr.ca/diary/wifi-data-apenwarr-201602.pdf
> 
> 
>> https://www.youtube.com/watch?v=Ey5jVUXSJn4
> 
> Haha.
> 
>> 
>> Bob
>> > Their post isn't really about bloat. It's about the discrepancy in i/o
>> > bw of memory off-chip and on-chip.
>> >
>> > My opinion is that the off-chip memory or hybrid approach is a design
>> > flaw for a serious router mfg. The flaw is thinking the links' rates
>> > and the chip memory i/o rates aren't connected when obviously they
>> > are. Just go fast as possible and let some other device buffer, e.g.
>> > the end host or the server in the cloud.
>> >
>> > Bob
>> >> https://blog.cerowrt.org/post/juniper/
>> >>
>> >> But they deleted the comment thread. It is interesting, I suppose, to
>> >> see how they frame the buffering problems to themselves in their post:
>> >> https://www.linkedin.com/pulse/sizing-router-buffers-small-new-big-sharada-yeluri/
>> > _______________________________________________
>> > Rpm mailing list
>> > Rpm at lists.bufferbloat.net
>> > https://lists.bufferbloat.net/listinfo/rpm


More information about the Rpm mailing list