I have Xfinity gigabit internet w/ no data cap, Arris SurfBoard SB8200 modem, NetGrear r7800 running OpenWRT 19.07
When I run speed test I get Download: 931.03 Mbps / Upload: 41.46 Mbps against netperf-west.bufferbloat.net and CloudFlare's 18.104.22.168. When I run iperf against my wan ip I get a very lousy ~4 Mbs with a few spikes up to 9 Mbs.
What gives with this poor ingress?
(I'm trying to troubleshoot streaming HD video from my network to my friends network. It was working good up till about 2 months ago. I'm just now getting around to troubleshooting.)
Your cable may be receiving ingress from outdated phone lines or FM signal from nearby cell towers. Check out my post here: https://forums.xfinity.com/t5/Your-Home-Network/Signal-ingress-due-to-outdated-neighborhood-phone-pr...
To narrow the issue, I recommend hooking up to Ethernet, installing pingplotter.com & then debugging by reading pingplotter's blog.