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To: cs551@merlot.usc.edu
Subject: Re: CS551 : Final project 1
Date: Mon, 06 Oct 2008 09:05:22 -0700
From: Bill Cheng <william@bourbon.usc.edu>

I forgot to mention...  This thread also acts as the
network-write thread in slide 19 of lecture 9.  Therefore,
it needs to check its input queue to see if there is work
to do, i.e., data to send.
--
Bill Cheng // bill.cheng@usc.edu <URL:http://merlot.usc.edu/william/usc/>



  -----Original Message-----
  Date: Mon, 06 Oct 2008 08:42:21 -0700
  From: Bill Cheng <william@bourbon.usc.edu>
  To: cs551@merlot.usc.edu
  Subject: Re: CS551 : Final project 1

  Someone wrote:
  
    > After the startup, every node will send hello to
    > every neighbor node. What the node (the client part) will do after the
    > startup??  Should it close the connection and exit the client thread??
    > If it close the connection then should it has to send notify message.
    > 
    > Hello should be sent at the start up time or before initiating a data
    > transfer??
    > 
    > If we have keepalive message then why we need hello?
  
  If you look at slide 14 of lecture 9, when you see that there
  is a line drawn between two nodes, it means that there is an
  *active* connection between the two nodes.
  
  If you close a connection, the link will be gone.
  
  On slide 19 of lecture 9, I have shown a design (just a
  design and not "the" design) where two threads are used per
  socket.  It's perfectly fine to use one thread per socket,
  like you are suggesting above.
  
  What does such a thread do?  Well, this is a network.  The
  main job for a node in the network is to *forward* packets.
  So, a thread would just wait for a packet to arrive,
  decrement its TTL, and decide what to do with the packet.
  
  If you decide to bring down an active connection, you should
  always send NOTIFY before you shutdown and close the socket.
  --
  Bill Cheng // bill.cheng@usc.edu <URL:http://merlot.usc.edu/william/usc/>