Transport protocols and bulk file transfer

[Brian Tierney <>]

Hi Stanislav:

Sorry I did not have time to join the call this morning, but I did read
the document. Overall I think its very good. I think it hits all the key
issues.

The only thing I disagree with is the statement on CPU requirements of  
UDP
vs TCP. I've heard from Bill Allcock of ANL that using UDT inside of  
GridFTP
instead of TCP used 2x the CPU (maybe this is due to the UDT  
implementation, not UDP).
I've done a bit of testing that shows that UDP CPU is higher too. I  
think you really
only see the difference at speeds great than 500 Mbps.

But despite the higher CPU, I think a user-space, UDP based solution is  
the way to go.

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  Brian L. Tierney,   Lawrence Berkeley National Laboratory (LBNL)
  1 Cyclotron Rd.  MS: 50B-2239,  Berkeley, CA  94720
  tel: 510-486-7381    fax: 510-495-2998   efax:  240-332-4065
  

   http://www-didc.lbl.gov/~tierney
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