Delivery-Date: Fri Oct 31 09:50:17 2008
Message-Id: <200810311702.m9VH2AjK029861@bourbon.usc.edu>
To: cs551@merlot.usc.edu
Subject: Re: cs551 is it a bug in grading-guideline?
Date: Fri, 31 Oct 2008 10:02:10 -0700
From: Bill Cheng <william@bourbon.usc.edu>

Someone wrote:

  > I'm not quite sure it's a bug in the grading-guideline:
  > 
  > ------------------------------------------------------------------------------
  > (C) Network with 2 beacon nodes : +22 points
  > ------------------------------------------------------------------------------
  > (2) (c) restart only 1 beacon plus all of the 4 regular nodes,
  >          all regular nodes should fail
  > The conclusion is true only when start 4 regular with -reset.
  > 
  > But if grader follows the sequence, (2)(a), (2)(b), (2)(c),
  > after (2)(b),
  > n03 has (n00,n01) in its init_neighbor_list;
  > n02 has (n00,n03) in its init_neighbor_list;
  > n08 has (n00,n01) in its init_neighbor_list.
  > Then in (2)(c), after starting n03, if grader starts n02 quickly,
  > n02 will connect n00 and n03 successfully, then keep alive.
  > Then n03 got neighbor n02 plus original n00, then also survive.
  > And n08 starts, thru n00, it could find new neighbors.
  > 
  > I've tested it with my code, but not sure.

I think you are correct if the nodes get started quickly.
Since JoinTimeout is 5 seconds, I should add "wait 10 seconds"
between the starting of the nodes to make sure that all
regular nodes will fail to start.

I'll update the grading guidelines soon.  Thanks for catching
the bug!
--
Bill Cheng // bill.cheng@usc.edu <URL:http://merlot.usc.edu/william/usc/>