Return-Path: william@bourbon.usc.edu Delivery-Date: Mon Apr 16 16:06:53 2007 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on merlot.usc.edu X-Spam-Level: X-Spam-Status: No, score=-3.3 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00, NO_REAL_NAME autolearn=ham version=3.1.3 Received: from bourbon.usc.edu (bourbon.usc.edu [128.125.9.75]) by merlot.usc.edu (8.13.5/8.13.5) with ESMTP id l3GN6rfY004777 for ; Mon, 16 Apr 2007 16:06:53 -0700 Received: from bourbon.usc.edu (localhost.localdomain [127.0.0.1]) by bourbon.usc.edu (8.13.5/8.13.5) with ESMTP id l3GN6x3A022310 for ; Mon, 16 Apr 2007 16:06:59 -0700 Message-Id: <200704162306.l3GN6x3A022310@bourbon.usc.edu> To: cs551@merlot.usc.edu Subject: Re: duplicate files detection and msg cache Date: Mon, 16 Apr 2007 16:06:59 -0700 From: william@bourbon.usc.edu Someone wrote: > As I understand, a node must no store duplicate file > (a file he already has) when receiving a store message. > Nonce can distinguish difference instance of the same > file, but how can we distinguish whether a file in store > message is what we already have, given that same > filename, keywords, sha1 are not enough to distinguish > two files? If you have a file in your mini-filesystem with the same filename, sha1, and nonce, as in your message, you should not store a copy of the file in your message. (I'm not sure exactly what you are asking.) > Secondly, if an intermediate node successfully forwards > message A (as part of flooding originated by this node's neighbor), > and later response to A back to the previous hop, should we > erase msg cache entry for A (since A's path is no longer > useful for routing)? No, it's not necessary. Since you already have a timeout mechanism to deal with this. -- Bill Cheng // bill.cheng@usc.edu