Re: [Cake] [Bloat] Two questions re high speed congestion management anddatagram protocols

Re: [Cake] [Bloat] Two questions re high speed congestion management anddatagram protocols

[David P. Reed]

Sorry for top posting, but ... Bigger question:
Why would DCCP be deprecated by Linux kernel?
Who makes that decision? Who argues against it?

It's a pretty good approach to properly congestion controlling many non-TCP communications protocols that might be implemented on UDP and lack good congestion control otherwise.
E.g. QUIC or RTP (for non CBR traffic) or various RPC-style  protocols. Larry Peterson recently wrote a piece asking why RPC wasn't well supported in distributed computing even after almost 50 years. Lack of Conception Control that works is a big issue. QUIC ain't it. QUiC is a HTTP replacement for REST protocol sementics.

So why discard a good thing that works?


-----Original Message-----
From: "Stephen Hemminger" <stephen@networkplumber.org>
Sent: Sun, Jun 25, 2023 at 2:51 pm
To: "David P. Reed via Bloat" <bloat@lists.bufferbloat.net>
Cc: "David P. Reed via Bloat" <bloat@lists.bufferbloat.net>, "Cake  List" <cake@lists.bufferbloat.net>
Subject: Re: [Bloat] Two questions re high speed congestion management anddatagram protocols

On Sat, 24 Jun 2023 14:41:52 -0400 (EDT)
"David P. Reed via Bloat"  wrote:

> I also was looking back to DCCP as a useful way to get a UDP that handled congestion without engaging the higher layers, and preserving the other flexibility of UDP.

DCCP never got widely used, and Linux is on the path of deprecating it.

Re: [Cake] [Bloat] Two questions re high speed congestion management anddatagram protocols

[Stephen Hemminger]

On Mon, 26 Jun 2023 23:41:59 -0400 (EDT)
"David P. Reed" <dpreed@deepplum.com> wrote:

> Sorry for top posting, but ... Bigger question:
> Why would DCCP be deprecated by Linux kernel?
> Who makes that decision? Who argues against it?

No one uses it, and unused protocols are targeted by hackers.
And there are few tests and no maintainer.

Re: [Cake] [Bloat] Two questions re high speed congestion management anddatagram protocols

[David Lang]

On Mon, 26 Jun 2023, David P. Reed via Bloat wrote:

> Sorry for top posting, but ... Bigger question:
> Why would DCCP be deprecated by Linux kernel?
> Who makes that decision? Who argues against it?

Linus or the networking maintaners make the decision.

Usually things get pulled from the kernel because there are updates that need to 
be made to the code (to match changes elsewhere in the kernel or because of 
security issues) and there isn't a maintainer who works on the code in a 
resonable time. This means that the maintainers for the general code area (in 
this case networking maintainers) will need to do extra work in an area they 
aren't that interested in (and, especially in the case of hardware, may not have 
the ability to test). They do some of it, especially if it's commonly used, but 
eventually either another maintainer steps up, or it goes away

David Lang

Re: [Cake] [Bloat] Two questions re high speed congestion management anddatagram protocols

[Stephen Hemminger]

On Tue, 27 Jun 2023 12:47:01 -0700 (PDT)
David Lang <david@lang.hm> wrote:

> On Mon, 26 Jun 2023, David P. Reed via Bloat wrote:
> 
> > Sorry for top posting, but ... Bigger question:
> > Why would DCCP be deprecated by Linux kernel?
> > Who makes that decision? Who argues against it?  
> 
> Linus or the networking maintaners make the decision.
> 
> Usually things get pulled from the kernel because there are updates that need to 
> be made to the code (to match changes elsewhere in the kernel or because of 
> security issues) and there isn't a maintainer who works on the code in a 
> resonable time. This means that the maintainers for the general code area (in 
> this case networking maintainers) will need to do extra work in an area they 
> aren't that interested in (and, especially in the case of hardware, may not have 
> the ability to test). They do some of it, especially if it's commonly used, but 
> eventually either another maintainer steps up, or it goes away
> 
> David Lang

See https://patchwork.kernel.org/project/netdevbpf/patch/20230614194705.90673-3-kuniyu@amazon.com/

Re: [Cake] [Bloat] Two questions re high speed congestion management anddatagram protocols

[Dave Taht]

https://datatracker.ietf.org/doc/charter-ietf-ccwg/

is a new wg intended to poke into these issues

On Tue, Jun 27, 2023 at 4:49 PM Stephen Hemminger via Cake
<cake@lists.bufferbloat.net> wrote:
>
> On Tue, 27 Jun 2023 12:47:01 -0700 (PDT)
> David Lang <david@lang.hm> wrote:
>
> > On Mon, 26 Jun 2023, David P. Reed via Bloat wrote:
> >
> > > Sorry for top posting, but ... Bigger question:
> > > Why would DCCP be deprecated by Linux kernel?
> > > Who makes that decision? Who argues against it?
> >
> > Linus or the networking maintaners make the decision.
> >
> > Usually things get pulled from the kernel because there are updates that need to
> > be made to the code (to match changes elsewhere in the kernel or because of
> > security issues) and there isn't a maintainer who works on the code in a
> > resonable time. This means that the maintainers for the general code area (in
> > this case networking maintainers) will need to do extra work in an area they
> > aren't that interested in (and, especially in the case of hardware, may not have
> > the ability to test). They do some of it, especially if it's commonly used, but
> > eventually either another maintainer steps up, or it goes away
> >
> > David Lang
>
> See https://patchwork.kernel.org/project/netdevbpf/patch/20230614194705.90673-3-kuniyu@amazon.com/
> _______________________________________________
> Cake mailing list
> Cake@lists.bufferbloat.net
> https://lists.bufferbloat.net/listinfo/cake



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Dave Täht CSO, LibreQos