Return-Path: william@bourbon.usc.edu Delivery-Date: Thu May 3 22:14:02 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 l445E2kn006242 for ; Thu, 3 May 2007 22:14:02 -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 l445D6Xh025247 for ; Thu, 3 May 2007 22:13:06 -0700 Message-Id: <200705040513.l445D6Xh025247@bourbon.usc.edu> To: cs551@merlot.usc.edu Subject: Re: Snoop operation Date: Thu, 03 May 2007 22:13:06 -0700 From: william@bourbon.usc.edu Someone wrote: > On p. 34 of Lec. 24, what does "greater than last ACKed, > pass on" correspond to in the flowchart on the left? This corresponds to the "No" arrow out of "In-sequence". This is the case of a congestion loss. > Also, in the flowchart, if a new packet is out of sequence, > how could we immediately say that it is "congestion loss" > (the red font under the box)? I think the idea of snoop > is to abate TCP's overreaction to packet loss (some > caused by wireless environment not congestion). "Congestion loss" means that a packet is dropped by a congested router in the Internet. This is what TCP assumes when any packet is lost. -- Bill Cheng // bill.cheng@usc.edu