Return-Path: william@bourbon.usc.edu Delivery-Date: Fri Oct 31 09:50:17 2008 X-Spam-Checker-Version: SpamAssassin 3.2.3 (2007-08-08) on merlot.usc.edu X-Spam-Level: X-Spam-Status: No, score=-2.4 required=5.0 tests=AWL,BAYES_00 autolearn=ham version=3.2.3 Received: from bourbon.usc.edu (bourbon.usc.edu [128.125.9.75]) by merlot.usc.edu (8.14.1/8.14.1) with ESMTP id m9VGoHrb019047 for ; Fri, 31 Oct 2008 09:50:17 -0700 Received: from bourbon.usc.edu (localhost.localdomain [127.0.0.1]) by bourbon.usc.edu (8.14.2/8.14.1) with ESMTP id m9VH2AjK029861 for ; Fri, 31 Oct 2008 10:02:10 -0700 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 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