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To: cs551@merlot.usc.edu
Subject: Re: neighbor vs. HELLO
Date: Mon, 27 Oct 2008 16:37:13 -0700
From: Bill Cheng <william@bourbon.usc.edu>

Someone wrote:

  > My question is more that you get a hello msg from someone that is not your
  > neighbor, but you are their neighbor....do they become your neighbor or do
  > you just respond with a HLLO  and not use it if you were to Flood a msg
  > later on? 

Sorry that I misunderstood your question.

"Initial neighbor" is a one-way relationship, i.e., if B is
in A's init_neighbor_list file, then B is A's "initial neighbor".
So, this is about what's in the init_neighbor_list file.

"Neighbor" is a two-way relationship, i.e., if X is Y's neighbor
then Y is X's neighbor.

In your scenario, A is not B's "initial neighbor".  A should
say HELLO back and now A and B are "neighbors" and this
connection is now an active connection.
--
Bill Cheng // bill.cheng@usc.edu <URL:http://merlot.usc.edu/william/usc/>




  -----Original Message-----
  From: Bill Cheng [mailto:william@bourbon.usc.edu] 
  Sent: Monday, October 27, 2008 2:38 PM
  To: cs551@merlot.usc.edu
  Subject: RE: neighbor vs. HELLO
  
  Someone wrote:
  
    > Does this mean that B is a neighbor of A and A is a neighbor of B or
  that
    > you should just always respond to a Hello msg. Seems like it could be
    > interpreted either way? "Please note that neighbor is a bi-directional
    > relationship. Therefore, when node B gets a hello message from node A,
  and
    > node A is not currently node B's neighbor, node B should send a hello
    > message to node A."
  
  If you get a HELLO, you should always respond with a HELLO,
  *unless* there is another connection and you have decided that this
  connection should be closed.
  
  In this case, since this is an "extra" connection and you are going to close
  it anyway, it doesn't really matter how you close it.  You don't have to
  send HELLO.  But it's okay if you send HELLO and then close.  If you'd like,
  you can also send HELLO and NOTIFY and then close.  It doesn't really matter
  here.
  --
  Bill Cheng // bill.cheng@usc.edu <URL:http://merlot.usc.edu/william/usc/>