Re: [tcpm] WGLC: NCR draft-ietf-tcpm-tcp-dcr-06.txt ENDS 27 Jan 2006

Mark Allman wrote:
> This is not clear to me.  In fact, it's not clear to me exactly how
> fairness comes into this.  If there were 2 flows over some path and no
> reordering then we'd expect them to see about the same performance
> (about half the bandwidth).  Now, if there was reordering and neither
> did NCR then they would each get less than half the bandwidth -- say
> they each got 1/4 the bandwidth, just to put some numbers on things.
> So, now the reordering is causing a 50% slowdown in the flows and less
> than full utilization.

Wait - you're arguing too far from an assumption, I think.

Does reordering have as bad an effect on a congested link
as on an uncongested link?  Or is it more like a 5% penalty
(congested) and 50% (congested).   If so, there's potential
for NCR to improve the situation for the flow using it to,
say, 3/4 of the bandwidth - leaving the non-NCR user only
getting 95% of 1/4 of the bandwidth.

Possibly this is what you mean later:

 >if the NCR flow ended up with 7/8 of the capacity and drove the non-NCR
 >flow to 1/8 of the capacity ... well, then there is a question.

and I didn't see the steps in your reasoning.  I'd call it unfair,
but justified.

In any case, I'm not arguing against the draft becoming Experimental.

Cheers,
     Jeremy Harris

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