Return-Path: william@bourbon.usc.edu Delivery-Date: Sun Dec 7 19:39:37 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 mB83dbdu002114 for ; Sun, 7 Dec 2008 19:39:37 -0800 Received: from bourbon.usc.edu (localhost.localdomain [127.0.0.1]) by bourbon.usc.edu (8.14.2/8.14.1) with ESMTP id mB83fWfR031228 for ; Sun, 7 Dec 2008 19:41:32 -0800 Message-Id: <200812080341.mB83fWfR031228@bourbon.usc.edu> To: cs551@merlot.usc.edu Subject: Re: Weighted fair Queueing Date: Sun, 07 Dec 2008 19:41:32 -0800 From: Bill Cheng SOmeone wrote: > In the weighted fair queuing example in slide 19 of lecture 17, > you indicated that we shrink packet sizes by 2 > Does this imply that if Y2 arrives at logical time 1.5, it will > depart at logical time 2 because packet size is now half (instead > of the original departure at 2.5)? Exactly! For a packet whose weight is 2, it's packet size is effectively shrunk by 50%. > You also indicated that we count Y twice when queue Y is not > empty. Does thisimply that we can have a slope of 1/4 if we have > up to two packets from Y in service and both X and Z also have a > packet each in service? No exactly. The slope is 1/4 if there is at least one packet in each queue. (The slope is 1/3 if there is at least one packet in queue Y and at least one packet in queue X or Z.) -- Bill Cheng // bill.cheng@usc.edu