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From: Jonathan Morton <chromatix99@gmail.com>
To: Sebastian Moeller <moeller0@gmx.de>
Cc: "Bless, Roland (TM)" <roland.bless@kit.edu>, bloat@lists.bufferbloat.net
Subject: Re: [Bloat] Questions for Bufferbloat Wikipedia article
Date: Wed, 7 Apr 2021 00:36:23 +0300	[thread overview]
Message-ID: <02488D80-24C0-42E6-A4C6-81F7402DC58E@gmail.com> (raw)
In-Reply-To: <2C969F6A-660D-4806-8D46-5049A2E96F74@gmx.de>

> On 7 Apr, 2021, at 12:30 am, Sebastian Moeller <moeller0@gmx.de> wrote:
> 
> I still think that it is not completely wrong to abstractly say BBR evaluates RTT changes as function of the current sending rate to probe the bottlenecks capacity (and adjust its sending rate based on that estimated capacity), but that might either indicate I am looking at the whole thing at too abstract a level, or, as I fear, that I am simply misunderstanding BBR's principle of operation...

It might be more accurate to say that it estimates the delivery rate at the receiver by observing the ack stream, and aims to match that with the send rate.  There is some periodic probing upwards to see if a higher delivery rate is possible, followed by a downwards drain cycle which, I think, pays some attention to the observed RTT.  And there is also a cwnd mechanism overlaid as a safety valve.

Overall, it's very much a hybrid approach.

 - Jonathan Morton

  reply	other threads:[~2021-04-06 21:36 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-05 12:46 Rich Brown
2021-04-05 15:13 ` Stephen Hemminger
2021-04-05 15:24   ` David Lang
2021-04-05 15:57     ` Dave Collier-Brown
2021-04-05 16:25     ` Kelvin Edmison
2021-04-05 18:00 ` [Bloat] Questions for Bufferbloat Wikipedia article - question #2 Rich Brown
2021-04-05 18:08   ` David Lang
2021-04-05 20:30     ` Erik Auerswald
2021-04-05 20:36       ` Dave Taht
2021-04-05 21:49 ` [Bloat] Questions for Bufferbloat Wikipedia article Sebastian Moeller
2021-04-05 21:55   ` Dave Taht
2021-04-06  0:47   ` Erik Auerswald
2021-04-06  6:31     ` Sebastian Moeller
2021-04-06 18:50       ` Erik Auerswald
2021-04-06 20:02         ` Bless, Roland (TM)
2021-04-06 21:59           ` Erik Auerswald
2021-04-06 23:32             ` Stephen Hemminger
2021-04-06 23:54               ` David Lang
2021-04-07 11:06             ` Bless, Roland (TM)
2021-04-27  1:41               ` Dave Taht
2021-04-27  7:25                 ` Bless, Roland (TM)
2021-04-06 20:01       ` Bless, Roland (TM)
2021-04-06 21:30         ` Sebastian Moeller
2021-04-06 21:36           ` Jonathan Morton [this message]
2021-04-07 10:39           ` Bless, Roland (TM)
2021-04-06 18:54 ` Neil Davies

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