From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rick Jones Subject: Question about David's blog entry for NetCONF 2006, Day 1 Date: Thu, 21 Sep 2006 15:15:14 -0700 Message-ID: <45130EF2.2090509@hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from palrel13.hp.com ([156.153.255.238]:49813 "EHLO palrel13.hp.com") by vger.kernel.org with ESMTP id S1751683AbWIUWPP (ORCPT ); Thu, 21 Sep 2006 18:15:15 -0400 Received: from tardy.cup.hp.com (tardy.cup.hp.com [15.244.56.217]) by palrel13.hp.com (Postfix) with ESMTP id 08CB537636 for ; Thu, 21 Sep 2006 15:15:23 -0700 (PDT) Received: from [127.0.0.1] (localhost [127.0.0.1]) by tardy.cup.hp.com (8.9.3 (PHNE_28810)/8.9.3 SMKit7.02) with ESMTP id PAA24763 for ; Thu, 21 Sep 2006 15:15:14 -0700 (PDT) To: Linux Network Development list Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org I was reading David's blog entries on the netdev meeting in Japan, and have a question about this bit: > Currently, things like Xen have to put the card into promiscuous > mode, accepting all packets, which is quite inefficient. Is the inefficient bit meant for accepting all packets, or more broadly that the promiscuous path is quite inefficient compared to the non-promiscuous path? I ask because I would have thought that if the system were connected to a switch (*), the number of packets received through a NIC in promiscuous mode would be nearly the same as when it was not in promiscuous mode - the delta being (perhaps) multicast frames. rick jones (*) "Today," it seems 99 times out of 10 systems are connected to switches not hubs.