[Bloat] The Register; How TCP's congestion control saved the internet

[Dave Taht]

John Nagle showed up on the related hackernews thread:

https://news.ycombinator.com/item?id=37633743#37637357


Animats 23 hours ago | root | parent | next [–]

> If everyone played nice, the exponential backoff timers would work as expected,

Yes. As I wrote in 1985, in [1], under "Game Theoretic Aspects of
Network Congestion" and "Fairness in Packet Switching Systems", about
fair queuing,

We would like to protect the network from hosts that are not
well-behaved. More specifically, we would like, in the presence of
both well-behaved and badly-behaved hosts, to insure that well-behaved
hosts receive better service than badly-behaved hosts. We have devised
a means of achieving this.

The goal of fair queuing is not to improve network performance
overall. The goal of fair queuing is to reward well-behaved hosts over
badly-behaved hosts. If everyone is well-behaved, the queue lengths
are the same, usually 1 or 0, and fair queuing does little.

There is an inherent conflict between this goal and achieving maximum
data transfer rates. If you try for near 100% utilization, the
problems become much worse. You can run comfortably at maybe 70%. This
was an accepted tradeoff for DoD systems. DoD wants things to keep
working in a crisis, even if normal operation is a bit slower.

This is why I'm not a big fan of HTTP/3. It's a attempt to get about
10% more performance in the good case, at the cost of considerable
extra complexity and less immunity to gaming the system.

I never wrote about that much at the time, because if I had, people
would have realized earlier that traffic shaping is possible, which
implies that you can sell and bill for bandwidth and quality of
service. We might have ended up with pay per packet.

[1] https://www.rfc-editor.org/pdfrfc/rfc970.txt.pdf

reply

On Mon, Sep 25, 2023 at 2:18 PM Dave Taht <dave.taht at gmail.com> wrote:
>
> This is possibly the first time the word bufferbloat has made the
> register. I hope it is not the last.
>
> Although the author called out van´s early work, he seems to have
> missed it was also van and kathie on codel, and he was also on the BBR
> team.
>
> What would have happened to the net without van?
>
> On Mon, Sep 25, 2023 at 1:34 PM Kenneth Porter via Bloat
> <bloat at lists.bufferbloat.net> wrote:
> >
> > <https://www.theregister.com/2023/09/24/tcp_congestion_control_internet/>
> >
> > _______________________________________________
> > Bloat mailing list
> > Bloat at lists.bufferbloat.net
> > https://lists.bufferbloat.net/listinfo/bloat
>
>
>
> --
> Oct 30: https://netdevconf.info/0x17/news/the-maestro-and-the-music-bof.html
> Dave Täht CSO, LibreQos



-- 
Oct 30: https://netdevconf.info/0x17/news/the-maestro-and-the-music-bof.html
Dave Täht CSO, LibreQos