[Cake] isp economics

Pete Heist pete at heistp.net
Sat Jul 28 16:00:18 EDT 2018

> On Jul 28, 2018, at 9:03 PM, Dave Taht <dave.taht at gmail.com> wrote:
> under load on the NanoStation 5 AC Loco’s I got for the camp’s backhaul. Is it really that good? This is in contrast to the 50+ms I see with rrul_be on the NanoStation M5 (without controlling the queue). 
> ubnt both cases? doubt it's the same bandwidth both cases. should be proportional to the latency you are seeing. running 2x2 incurs a latency penalty also.

Higher bandwidth on the newer AC Loco vs the M5 but not a huge difference (120Mbit one-way vs 90Mbit one-way). Both 20 MHz channels. The AC Loco defaults to 80 MHz channels, which is excessive for this application.
> This test is straight AP to AP though, with probably 1 flow up and 1 down plus ping, so I want to get 2-4 more of these and do rrul_be through the Ethernet ports, to get more flows and UDP, and see how it looks then.
> Run more flows. SFQ is per packet fq. They have right-sized buffers when the link is running at close to the configured rate, not when it's stuggling.

I think that’s the primary reason (the way ubnt does their test), unfortunately don’t have two free to test at the moment.

> I also seem to remember they reduced the txop to ~2ms. turned off 802.11e. I've recommended this for years now in the general case. 

Re 802.11e, what’s interesting is when you run ’athstats’ on the NSM5 (older), there’s a breakdown of BK, BE, VI and VO packet stats. On the AC Loco (newer), there’s not. That does imply, but doesn’t prove, that they don’t use these queues, at least for point-to-point connections. I think they have to have 802.11e to be compliant, but I don’t know if they're mapping everything to one queue or not.

It looks like airMAX is now _not_ used at all for point-to-point connections, whereas it used to be on their older gear. This is good, as my testing showed airMAX only adds a bit of inter-flow latency for point-to-point.

> Their 100mbit ethernet devices also do flow control and are more often the bottleneck than not, so the wifi runs empty more often. 

The AC Loco has Gbit Ethernet thankfully. Looks to me like all of their AC gear does now.

Sorry for diverging too far from the ISP topic, and on the Cake list…

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