[e2e] Bandwidth Estimation workshop

David P. Reed dpreed at reed.com
Tue Sep 30 12:20:34 PDT 2003

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

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 

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 

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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