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Re: [tsvwg] The List (of application-layer desired features)

From: (wrong string) 陈智昌 <willchan@chromium.org>
Date: Wed, 4 Sep 2013 15:20:28 -0700
Message-ID: <CAA4WUYiu1DRz302uwBWzuMdT1RsEfWGOU_NTsrwSGJuvn-j0AQ@mail.gmail.com>
To: Michael Tuexen <Michael.Tuexen@lurchi.franken.de>
Cc: Roberto Peon <grmocg@gmail.com>, Yuchung Cheng <ycheng@google.com>, Joe Touch <touch@isi.edu>, HTTP Working Group <ietf-http-wg@w3.org>, tsvwg <tsvwg@ietf.org>
On Wed, Sep 4, 2013 at 2:58 PM, Michael Tuexen <
Michael.Tuexen@lurchi.franken.de> wrote:

> On Sep 4, 2013, at 9:43 PM, Roberto Peon <grmocg@gmail.com> wrote:
>
> > I suspect that Yuchung meant 'widely deployed and available', when he
> says 'always'. That should certainly be true for TCP.
> That is definitely true for TCP.
> However, why do you need an alternate solution to be "widely deployed".
> Can't it
> be deployed within the browser?
>

I think people are being too imprecise which leads to confusion. UDP is
widely deployed. A UDP based solution can be deployed within the browser.
TCP-AO is not widely deployed. It cannot be deployed within the browser.

For me it makes sense to require "availability" and "having a sufficient
> level of connectivity".

>
> > Personally, I think that UDP encapsulated stuff has a fighting chance.
> Deployment is a matter of addressing any new features and protocol
> technical issues of the current non end-to-end internet, and sticking a
> binary on participating machines.
> > This is a reasonably bounded problem, thus, has a fighting chance.
> >
> > I suspect that, without kernel support for interpacket delay measurement
> and interpacket gap enforcement, any such protocols will do worse than they
> would with such support, but hopefully that is about enhancement and not
> required to make something new work well.
> This sounds to me like a performance optimisation. I guess this might be
> one feature
> of a larger set of features which improve the overall performance.
> However, the
> connectivity must be there at all. My expectation is that anything running
> over
> UDP might not have the same level of connectivity, but it should be
> acceptable.


> Best regards
> Michael
> >
> > -=R
> >
> >
> > On Wed, Sep 4, 2013 at 11:40 AM, Michael Tuexen <
> Michael.Tuexen@lurchi.franken.de> wrote:
> >
> > On Sep 4, 2013, at 7:52 PM, Yuchung Cheng <ycheng@google.com> wrote:
> >
> >> On Wed, Sep 4, 2013 at 10:12 AM, Joe Touch <touch@isi.edu> wrote:
> >>>
> >>>
> >>> On 9/4/2013 8:21 AM, Yuchung Cheng wrote:
> >>> ...
> >>>
> >>>> Here is a problem I don't think there is a good practical solution:
> >>>> multi-flows. Currently browser uses some heuristics to determine
> >>>> number of parallel connections to trade-off latency and congestion,
> >>>> because the transport does not provide a good service for that.
> >>>
> >>>
> >>> Transports don't read minds.
> >>>
> >>>
> >>>> HTTP/2 reduces one factor by limiting #connections per host to 1 but
> >>>> that's
> >>>> not enough.
> >>>
> >>>
> >>> That's not an appropriate solution - and it's the sort of "mis-use" I
> was
> >>> referring to. It only serves to push muxing up the stack.
> >> The transport(s) that can keep muxing down the stack don't always run
> >> on the Internet. This is what Roberto's argument is about.
> > I think "running always" is hard... Not sure if TCP does.
> > So what about UDP encapsulated stuff like SCTP/UDP?
> >
> > Best regards
> > Michael
> >>
> >>>
> >>>
> >>>> IMHO the transport (tcp, sctp, quic, or anything you
> >>>> prefer) should just take connection priorities dynamically from the
> >>>> app, and schedule connections more intelligently at the receiver. It's
> >>>> not the app's job or can he do a good job at higher layer.
> >>>>
> >>>> There is an old work called congestion manager but it's not useful b/c
> >>>> it's sender based.
> >>>
> >>>
> >>> RFC2140 avoids sets of connections from both getting more than their
> >>> steady-state fair-share, and reduces the amount they step on each
> other.
> >>> It's already deployed, but might benefit from some app-layer hints.
> >>>
> >>> IMO, this isn't a "transport" problem, though - it's more like a
> missing
> >>> coordination layer (whether implemented with headers and state or just
> an
> >>> API to the OS).
> >> Any name is fine with me as long as the solution works.
> >>
> >>>
> >>> Joe
> >>
> >>
> >
> >
>
>
>
Received on Wednesday, 4 September 2013 22:20:58 UTC

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