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Any cable modem brands known to not use bufferbloat-ing NICs?



DOCSIS 3.1 standard introduced a good but not great Active Queue Management scheme called PIE. But upgrading your modem only helps with traffic you're sending; your ISP needs to upgrade their equipment to manage the buffers at their end of the bottleneck in order to prevent your downloads from causing excessive induced latency.


The bufferbloat project introduced a great (IMHO) fq + AQM scheme called "cake", which smokes the DOCSIS 3.1 pie in every way, especially with it's new DOCSIS shaper mode in place. It's readily available in a ton of home routers now, notably openwrt, which took it up 3 years ago. It's also now in the linux mainline as of linux 4.19. The (first of several) papers on it is here: https://arxiv.org/abs/1804.07617

I hope to have a document comparing it to docsis 3.1 pie at some point in the next few months, in the meantime, I hope more (especially ISPs in their default gear) give cake a try! It's open source, like everything else we do at bufferbloat.net and teklibre.


Use a decent router on your side and configure it to rate limit slightly below the modems's limits. This avoids ever creating a queue in their boxes. You can run a ping while tweaking your router rate limit settings to find the point where it is just about queuing but not quite, to optimize both throughput and latency.


Depending on your speed, you may need a bit more than just a decent router. Many routers can't hardware accelerate qos traffic, which will be needed to limit the speed.

My Netgear R7000 can't handle my 400mbps connection using qos throttling. I will need probably at least a mid range Ubiquiti router to handle it.


Ubiquiti routers won't help you; they're even more reliant on hardware acceleration than typical consumer brands, and nobody has put the best modern AQM algorithms into silicon yet. What you really need is a CPU fast enough to perform traffic shaping and AQM in software, which ironically means x86 and Intel are the safest choices.


Well, bufferbloat is at it's worst on slow connections (<100Mbit) and 50 dollars worth of router can fix it there in software.


Only if the firmware implements the algorithms. OpenWRT is your best bet for this: I have it running on a TL-WDR3600 quite well.


> Any cable modem brands known to not use bufferbloat-ing NICs?

Avoid modems with Intel, specifically the various "Puma" chipsets. Best to double-check the spec sheet on whatever you buy.

The main alternative seems to be Broadcom-based modems: TP-Link TC7650 DOCSIS 3.0 modem and Technicolor TC4400 DOCSIS 3.1 modem (of which there are a few revisions now).


A $45 router is enough to de-bufferbloat connections up to several hundred megabits, and past that bufferbloat is less of a concern (in part because its difficult to saturate).


My $120+ Netgear r7000 can't quite handle my 400mbps connection when qos filtering is turned on. If anyone wants a reference.


There are cheap and good routers.

$69 MikroTik hAP ac2 will easily push 1Gbps+ with qos rules - https://mikrotik.com/product/hap_ac2#fndtn-testresults (it's a bit more tricky to setup and you need to make sure you don't expose the interface to the internet)


It's not the hardware that's at fault, it's the software and/or configuration. See here: https://news.ycombinator.com/item?id=17448022




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