Throughput issues on Wave G/CondoInternet (Redmond, WA)

Hi NANOG mailing list,

I have Wave G "Gigabit" service in Redmond, WA, and download speeds have been slow. Wave G is Wave Broadband's MDU-focused Gigabit offering, and was formerly CondoInternet, although I joined only this year on a Wave G-branded service.

To Seattle, I cap at about 600-750 Mbps download while I get 900 Mbps uploads. To servers far away, it does gown to 10-30 Mbps while I can upload at 200-500 Mbps. The downloads speeds are far lower than what's normal from TCP (I **do** know higher latency == slower downloads).

The issue appears to be the window size being smaller on downloads on the routers on Wave G's side and that limits download throughput.

This is a Wireshark screenshot of a download test:

The green line is the window size, and the blue line is the outstanding bytes.

In comparison, this is a Wireshark screenshot of an upload test:

The download test shows a small window size and spikes in the outstanding bytes and this gets reset very often after the first increase instead of gradually using the pipe's full capacity and then resetting, showing the window size can't get higher.

The upload test shows a larger window size and a sawtooth shape of the outstanding bytes which is what should normally happen.

This happens on both FreeBSD 13-CURRENT and Windows 10, both hardwired and Wi-Fi. My work Windows 10 PC via RDP and personal FreeBSD VPS servers have no issues whatsoever to the same exact servers, both being in the Seattle metro.

"Tech Support" hasn't been helpful since they insist on a tech visit which I believe isn't needed ("Wave G" isn't Wave's DOCSIS offering, no HFC issues here), or blame the issue on something outside their network (these issues **don't** exist outside Wave G). Ziply/Frontier and CenturyLink aren't available here, and why would I go to Comcast's overpriced, asymmetrical, capped garbage?

If someone works for Wave Broadband, or more specifically on the Wave G service, please shoot me an private email so we can get this resolved (and I can share my service details and pcap file if necessary in the said private email).

-Neel Chauhan