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To: cs551@merlot.usc.edu
Subject: Re: CS551 - Final1
Date: Sat, 11 Oct 2008 19:51:45 -0700
From: Bill Cheng <william@bourbon.usc.edu>

Someone wrote:

  > Regarding Join:
  > 
  > Scenario: 3 non-beacon nodes starting up. 1 beacon-node already up and
  > blocked on accept().
  > 
  > When the 3 non-beacon nodes send join request messages, the beacon node
  > responds to the 3 nodes. Does this beacon node also forward the join request
  > to the non-beacon nodes ?

Yes.  The JOIN request gets *flooded* to the whole network
(if TTL is large enough).

  > Also, at some point the join timer expires and the non-beacon nodes see that
  > there is just one beacon node that they can connect to and they add that
  > beacon in their init_neighbor_list  file.

No.  It should receive JOIN responses from all nodes.  It
should sort the JOIN responses and write the winners to the
init_neighbor_list file.  It does not care if a response is
from a beacon node or not.

  > Now, if minNeighbors is greater than 1 and the join timeout has expired,
  > what should the non-beacon nodes do ? Just make that one beacon their
  > neighbor even if minNeighbors is greater than 1 ... OR .. would the other
  > non-beaon nodes be considered as potential neighbors ?

Please see above.

  > How does a non-beacon node make another non-beacon node its neigbor if it
  > doesn't send a Join request to the non-beacon nodes ?

A JOIN request gets flooded to the *whole* network and
every node responds.
--
Bill Cheng // bill.cheng@usc.edu <URL:http://merlot.usc.edu/william/usc/>




  On Thu, Oct 9, 2008 at 7:33 PM, Bill Cheng <william@bourbon.usc.edu> wrote:
  
  > Someone wrote:
  >
  >  > A few questions:
  >  >
  >  > -Does a Beacon node have to connect to all beacons and its init
  >  > neighborlist, or just its init_neighbor_list? If so after connecting to
  > all
  >  > beacon nodes and neighbors would a beacon node just consider the
  >  > neighborlist as neighbors from that point?
  >
  > A beacon node does not have a init_neighbor_list file
  > because it never performs a join.  Since a beacon node
  > is at the *core* of the network, it does not need to
  > discover/join the network.
  >
  >  > -Does a beacon node retry to connect to other beacon nodes only once
  > after
  >  > the retry amount specified in the input file or does it keep trying with
  >  > that length gap until shutdown?
  >
  > It must never stop retrying!
  > --
  > Bill Cheng // bill.cheng@usc.edu <URL:http://merlot.usc.edu/william/usc/>