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To: cs551@merlot.usc.edu
Subject: Re: About Bistro 
Date: Sun, 06 May 2007 16:15:12 -0700
From: william@bourbon.usc.edu

Someone wrote:

  > With reference to the earlier mail, the data transfer is, in a
  > sense, independent of the deadline.Does it mean that there
  > isnt any constraint on when the actual data is uploaded on any
  > intermediate bistro???

If the 2nd phase is not finished, the user may not be happy.
In the worst case, the 2nd phase (and 3rd phase) is skipped.
At the end, the event owner can send an e-mail to the user
and ask for the data with the right hash.

  > Also in the slide 27 of lecture 26 after the first step is over
  > how does this client gets the SESSION KEY?? I believe that the
  > destination bistro sends the SESSION KEY in the
  > way....Kpriv[h(T),Email,s,sigma,Kses]???Right??

No.  A random session key is generated by the client.  The
destination bistro does not have to know the session key
until the end of the 3rd phase.
--
Bill Cheng // bill.cheng@usc.edu <URL:http://merlot.usc.edu/william/usc/>




  ----- Original Message -----
  From: william@bourbon.usc.edu
  Date: Sunday, May 6, 2007 3:52 pm
  Subject: Re: About Bistro
  To: cs551@merlot.usc.edu
  
  > Someone wrote:
  > 
  >  > Is the "commit" phase (client-push) transparent to client?
  > 
  > I'm not sure what you meant by "transparent".  The client
  > has to push the data to a bistro server (any bistro server)
  > on the Internet.
  > 
  >  > What happens if a Bistro server is overloaded with "push".
  >  > I guess there will be a delay in upload of actual data (could
  >  > be very large for each client). If yes, how to determine
  >  > the length of the delay?
  > 
  > Once the first phase is completed, the time it takes for the
  > 2nd (commit) phase does not matter as far as the correctness
  > of the protocol is concerned.  If the 2nd phase takes too
  > long, the user might be upset that it's taking too long.  The
  > user can turn off his/her machine and restart the 2nd phase
  > at any time (even after the deadline).  So, the data transfer
  > is, in a sense, independent of the deadline.
  > 
  >  > Also, is it required that Bistro-like system be installed
  >  > on intermediary systems. Can they be installed on
  >  > destination server if scalability is OK?
  > 
  > Sure!  For our homework/project submission, the data is
  > uploaded to the destination bistro directly during the 2nd
  > phase.
  > --
  > Bill Cheng // bill.cheng@usc.edu 
  > <URL:http://merlot.usc.edu/william/usc/>