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From: Neal Cardwell <ncardwell@google.com>
To: Matt Mathis <mattmathis@google.com>
Cc: Dave Taht <dave.taht@gmail.com>,
	starlink@lists.bufferbloat.net,
	 bloat <bloat@lists.bufferbloat.net>
Subject: Re: [Bloat] starlink bloat in review
Date: Mon, 17 May 2021 11:08:25 -0400	[thread overview]
Message-ID: <CADVnQykudX4xz=LqgKPG40ejULCLME=mE-v8LFB+JBjGs8H7aA@mail.gmail.com> (raw)
In-Reply-To: <CAH56bmCLiwDYZqYm0dm31NtqAKXGhh8w43hunpXFssqQyCd1og@mail.gmail.com>

On Sat, May 15, 2021 at 7:00 PM Matt Mathis via Bloat
<bloat@lists.bufferbloat.net> wrote:
>
> I don't understand: starlink doesn't terminate the TCP connection,
> does it?   Or are you referring to YT's BBR adequately addressing
> Starlinks variable RTT?   "Adequately" is probably the operative word.
> It is not too hard to imagine what goes wrong with BBR if the actual
> path length varies, and on an underloaded network, you may not be able
> to even detect the symptoms.

On that note, the article mentions:
  "Starlink itself measures ping times for Counter-Strike: Go and
Fortnite in its app, and I rarely saw those numbers dip below 50ms,
mostly hovering around 85-115ms."

If the range 50ms to 115ms is representative of two-way propagation
delays on their network, then it sounds like BBR can probably perform
reasonably well in that environment. The algorithm is designed to
tolerate factor-of-two variations in RTT and still maintain full
utilization, if there is reasonable buffering.

neal

  reply	other threads:[~2021-05-17 15:08 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-15 22:07 Dave Taht
2021-05-15 22:59 ` Matt Mathis
2021-05-17 15:08   ` Neal Cardwell [this message]
2021-05-17 15:46     ` Jim Gettys
2021-05-17 15:49     ` [Bloat] [Starlink] " Nathan Owens

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