UDP vs. TCP distribution [was: Re: [e2e] Can feedback begenerated...]

[Joe Touch]

"David P. Reed" wrote:
> 
> At 05:55 PM 3/7/01 +0100, Sean Doran wrote:
> >It's not going to be cheaper to have an empty network than to have
> >one with a bottleneck here and there.
> 
> This presumes that customers want the lowest price regardless of
> delay.  Not true.  And in any case, operating a network with queues mostly
> full (which increases utilization) a lot of the time is great strategy if
> you want to maximize profit when you are being paid by the byte (or by the
> portal access rate).
> 
> Most applications benefit from low queueing delay, so this isn't about QoS
> differentiations.  Only FTPs with no human in the loop want capacity with
> no delay constraint.

NTP wants it too. 

Capacity can also be used to mask latency, PROVIDED the variability
in the feedback loop can be described (if not predicted). E.g., even
FTPs with people in the loop work - you send the whole directory
when the person does a "cd" (see Infocom 1995).

(both the above cases are related; the variability is derived
from the application, rather than the network).

Further, many interactive systems are more sensitive to variability
in the latency itself than in the latency value (e.g., NTP, it turns
out).

Joe