[e2e] Bandwidth Estimation workshop

Cannara cannara at attglobal.net
Thu Oct 2 10:20:50 PDT 2003

I'll, of course, second David!


"David P. Reed" wrote:
> At 11:27 AM 9/30/2003, Constantine Dovrolis wrote:
> >On a personal note: I teach CS-networking and my students know very well
> >the distinction between physical-layer bandwidth and network-layer
> >bandwidth.
> This is a distinction which I have not heard.   Do you have a textbook
> citation, or perhaps a citation of a survey paper, that provides such a
> distinction?
> I ask because "information rate" is well defined at both layers in
> bits/second, yet you would claim that the distinction depends on the layer.
> And here in my research group, we construct transport networks that operate
> in the RF domain, doing routing and switching using the medium and spatial
> modulation and filtering.   That "network layer" that we construct has a
> bandwidth that is measured in Hertz, which has nothing to do with the
> information rate, which is a function of the spatial sampling density and
> energy density (according to a law that looks a bit like a Shannon capacity
> theorem).
> My point is that by deliberately conflating the two meanings of bandwidth
> and defining them in terms of an arbitrary layering convention (network vs.
> physical), this pedagogy ennobles a pernicious form of ignorance - one in
> which systems such as the ones we are building here cannot even be
> described, because the terms taught prevent students from being able to
> express them.

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