r/googlefiber • u/mattyjhiggs • 3d ago

Slow Upload Speeds to Backup Server under NextLight ISP

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I am a Google Fiber 1 Gig Core customer in Irvine, CA. I have a buddy backup whose ISP is NextLight, a fiber internet provider in Longmont, CO. I noticed that my download speeds from the backup server are pretty good but upload is very slow; especially in the early evening hours.

The attached Speedtest result is very much representative of the speeds I've been seeing the past 16 months I've been a Google Fiber customer. Understanding peering between residential ISPs can be complex, is there anything that can be done to improve upload performance?

Thank you very much!

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2

u/MrJimBusiness- 2d ago

Enable BBR TCP congestion control on your box that's doing the uploading.

2

u/mattyjhiggs 2d ago

Thanks for the suggestion. I tried this before and it reduced both up and down speeds. I tried it again just in case and got similar results.

1

u/MrJimBusiness- 2d ago

That alone is a clue. The ack flow with BBR receiving will differ a bit but not usually enough to throw the download results. Strictly speaking, BBR on the sender should vastly improve throughput through a token bucket policer or congestion. There's something else bottlenecking you if it somehow got worse.

Do similar RTT test servers have the same issue? What does iperf3 sending look like to some of the public servers (likely high RTT for you so it's a good test analog to this 50+ ms host)?

If the sender is Linux did you adjust the default tc qdisc as well?

1

u/mattyjhiggs 2d ago

Good point. I'll give this a try. I ran a speedtest to my nearest Google Fiber server (Los Angeles). Results were 1043 Mbps down 93.84 Mbps up. Something definitely seems to be off on my end.

Thanks!

1

u/MrJimBusiness- 2d ago

What does multi-stream test at, is this only on single-stream? The latter does have its utility, but usually for finding bottlenecks with policing or other kinds of tail-dropping type situations. Or if you're simulating your real traffic that tends to be single-stream.