[e2e] TCP Local Area Normal behaviour? any references?

[Matt Mathis]

OK, you caught me!    It is easy to find pathological cases where you can get
no more than 50% utilization (full window in a single burst, gating all of
the acks on the return path.)

I think capture effect does not become a problem unless the end-system and
routers/switches can send true back-to-back packets for a large portion of the
window.  Just a small amount of idle makes the channel arbitration much more
fair.  It might be kind of interesting to try to reconstruct the Boggs result
with modern PC's.....

Thanks,
--MM--

On Fri, 21 Jan 2005, Craig Partridge wrote:

>
> In message <Pine.LNX.4.58.0501211335290.11281 at tesla.psc.edu>, Matt Mathis write
> s:
>
> >But the more pragmatic solution (adopted here at PSC and may other places) is
> >to declare half duplex Ethernet to be broken, and eradicate it wherever
> >possible.  Where not possible, tell people that the maximum theoretical
> >utilization is 1/e (35%), and they should be pleased if they get any better
> >than that, because they are operating beyond the designed operating point for
> >the media.
>
> That 1/e is not consistent with Boggs & Mogul's work from SIGCOMM 1988.
> Van Jacobson also reported results inconsistent with 1/e.  Indeed, I'd
> thought 1/e had generally been discredited as a mistaken result from
> inaccurate models.
>
> Boggs & Mogul used multiple TCP's.  Van used a single one.
>
> So what did they do such that the capture effect didn't happen?  And
> does capture really yield 1/e or something different?
>
> Craig
>