> > > Of course it can. It is totally trivial. None of
> > > this need be done in
> > > the kernel, or at the UDP layer.
> > 
> > which means over-burdening the application layer.
> 
> Inserting two bytes is an overburden? Come on. You
> don't even need the
> header checksum in the first place, but if you want
> it is burdensome
> to insert two bytes and check them later? That's
> ridiculous.

Its not the two bytes, its the processing overhead.
You also mentioned it and I also quote:

"the largest bottleneck to achieving high throughput
in this system is due to computing checksums" 
  J. Kay and J. Pasquale. Profiling and Reducing
Processing Overheads in TCP/IP. IEEE/ACM Transactions
of Networking, 4(6), December 1996. 

Apart from the checksum we need the priority mechanism
up there as well (how trivial it might be).

And with the error-rate of wireless networks I do want
to calculate header checksum.

Lastly, traditionally speaking this sure doesnt look
like an application layer functionality to me.


  -- Ali

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