Return-Path: william@bourbon.usc.edu Delivery-Date: Thu Oct 30 18:13:21 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 m9V1DLBl009192 for ; Thu, 30 Oct 2008 18:13:21 -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 m9V1P3dZ017274 for ; Thu, 30 Oct 2008 18:25:03 -0700 Message-Id: <200810310125.m9V1P3dZ017274@bourbon.usc.edu> To: cs551@merlot.usc.edu Subject: Re: CS551 Final1 Date: Thu, 30 Oct 2008 18:25:03 -0700 From: Bill Cheng Someone wrote: > From the spec: "The check message is used by a node to see if it is still > connected to the core of the SERVANT network." > The Beacon node is a part of the core of the SERVANT network. If a beacon > node goes down, the rest of the beacon nodes would keep retrying to connect > to this node. Then why should a beacon node send check message? You are absolutely correct. Sorry, I miss-read the question! (I guess I've been anwering too many e-mails!) Although my answer was correct (except for the "yes" part). I thought the question was about NOTIFY. -- Bill Cheng // bill.cheng@usc.edu On Thu, Oct 30, 2008 at 2:22 PM, Bill Cheng wrote: > Someone wrote: > > > Does a beacon node need to send check message when it loses > > connection from one of its neighbors? > > Yes. Remember, the rule is that if you have sent HELLO, > you need to send GOOD-BYE (i.e., NOTIFY). > > > If a beacon node's NoCheck=1 and a non-beacon node's NoCheck = 0, > > the beacon node will ignore the check message, so it means that > > the non-beacon node will think itself is not part of the network, > > is it right? > > This will never happen during grading. Either NoCheck=0 for > all nodes, or NoCheck=1 for all nodes. This is done so that > your part (2) does not depend on part (1) *completely* working > properly. > > > For Error Code of notify message, which value does timeout (Auto > > shutdown) use? > > Please see: > > http://merlot.usc.edu/cs551-f08/msgs/bill/341.txt > -- > Bill Cheng // bill.cheng@usc.edu