Summary:

ISP is Comcast Xfinity Gigabit cable. The network has about 25 connected devices. 935Mbps/39Mbps average over 16 speed tests with SQM disabled. C average grade on Bufferbloat tests.

After setting up SQM with minimal fuss over stock options, Bufferbloat is consistently A . Speeds now average 725Mbps/35Mbps.

Preface: The setup was cost-effective. The WAPs were $100 from eBay. The router was $55 from eBay. The XB7 allows unlimited data (Thanks Comcast -_-).

Hardware:

XB7 Cable Modem, Bridged

Linksys WRT1900ACSv2 Router w/ OpenWRT 19.07.8

Eero Pro 5 WAPs x2, Bridged, Wired

Without SQM:

According to https://www.waveform.com/tools/bufferbloat, Bufferbloat varied wildly from Download Active: up to 160ms, Upload Active: up to 80ms.

Example: https://www.waveform.com/tools/bufferbloat?test-id=d77e2654-f31f-4b6a-b1e6-e35b54d7d054

With SQM enabled:

Download and Upload Active: up to 3ms, often testing at 0. Consistently A .

Example: https://www.waveform.com/tools/bufferbloat?test-id=64650815-fcea-4ee0-93c4-e204fe0ebb2c

My Testing & SQM Settings:

Tested via ethernet (cat5e), I laid out a spreadsheet taking the average of 16 speed tests, using the (average x 80-95%) in 2.5% increments to find the best bufferbloat test scores. 90% of egress (upload) speeds and 80% of the ingress (download) speeds provided the best results.

I have download speed ingress shaping set to 748,549Kbps (80%), upload speed egress shaping set to 35,245Kbps (90%). Queue discipline is cake. The script is piece of cake with ‘nat dual-dsthost’ & ‘nat dual-srchost’ set in the advanced ingress and egress queueing disciplines, respectively. Link-layer adaption is set to ‘Ethernet with overhead,’ 44 per-packet overhead.

Conclusion:

Couldn’t be happier. The only trouble I encountered was using OpenWRT 21.02.1 with the WRT1900ACSv2 wouldn’t let SQM work properly. Cursory research suggested the router only operates in single-core with the latest OpenWRT firmware rev. Down revving to 19.07.8 resolved my SQM issues.