Re: [Roll] using the flow label instead of hop by hop

[Philip Levis <[e-mail]>]

On Oct 20, 2012, at 1:19 AM, Pascal Thubert (pthubert) wrote:

> Phil;
> 
> There is indeed lot of pressure for this in terms of header sizes and energy consumption in the *real world*.

I'm personally concerned about header sizes and energy consumption in The Matrix. Because I don't live in the real world. Oh, wait, sorry, I do. Can you walk me through the quantitative reasoning that a few bytes of header will increase energy consumption? It the belief that it will lead to sub-packet fragmentation in some non-amortized sense? Generally speaking, in low power wireless networks, energy consumption is dominated by idle listening and communication latency/interval support, not the length of packets. Of course there is a spectrum of low power approaches and their point on that spectrum. Are you thinking of one in particular?

Could implementers who are encountering this pressure comment? I'm a sucker for and easily swayed by quantitative data as well as first-hand rather than second-hand reports.

> And there is no hack in the proposed solution.
> Simply we believe more in practical engineering and ML discussions than we trust in crystal balls. 

*coughs politely* I believe in very practical engineering that considers long term consequences. Solving a problem a certain way now might cause significant problems in the future. I agree this is a tradeoff -- in my personal opinion, nothing more, the tradeoff on this one is 100% clear.

Phil

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Philip Levis
President, Kumu Networks
Associate Professor, Stanford University
http://csl.stanford.edu/~pal