Return-Path: william@bourbon.usc.edu Delivery-Date: Fri Oct 31 12:58:37 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 m9VJwbRP021043 for ; Fri, 31 Oct 2008 12:58:37 -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 m9VKANvK001324 for ; Fri, 31 Oct 2008 13:10:23 -0700 Message-Id: <200810312010.m9VKANvK001324@bourbon.usc.edu> To: cs551@merlot.usc.edu Subject: Re: cs551 is it a bug in grading-guideline? Date: Fri, 31 Oct 2008 13:10:23 -0700 From: Bill Cheng Someone wrote: > Node doesn't fwd join request to temporary link(haven't receive hello), > is it correct? Correct. > So I guess in (c)(2)(a),(c)(3)(a), and(c)(3)(b), we should also wait 10 > seconds between the starting of the nodes. Otherwise, if we start all > regular nodes one after another very quickly, all regular nodes will > have neighbors only with beacon nodes. I think so, but not sure. Usually, it takes time to switch window. So, for JoinTimeout=5, we don't need to wait extra time. The grader will not be "starting nodes as fast as she can". The normal thing is to start a node, observe that it's doing the right thing, before starting another node. -- Bill Cheng // bill.cheng@usc.edu Bill Cheng wrote: > 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