From owner-freebsd-arch@FreeBSD.ORG Fri Nov 11 14:15:24 2005 Return-Path: X-Original-To: arch@FreeBSD.org Delivered-To: freebsd-arch@FreeBSD.ORG Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 62B0016A41F for ; Fri, 11 Nov 2005 14:15:24 +0000 (GMT) (envelope-from glebius@FreeBSD.org) Received: from cell.sick.ru (cell.sick.ru [217.72.144.68]) by mx1.FreeBSD.org (Postfix) with ESMTP id B1B6C43D49 for ; Fri, 11 Nov 2005 14:15:23 +0000 (GMT) (envelope-from glebius@FreeBSD.org) Received: from cell.sick.ru (glebius@localhost [127.0.0.1]) by cell.sick.ru (8.13.3/8.13.3) with ESMTP id jABEFKhw041764 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Fri, 11 Nov 2005 17:15:21 +0300 (MSK) (envelope-from glebius@FreeBSD.org) Received: (from glebius@localhost) by cell.sick.ru (8.13.3/8.13.1/Submit) id jABEFKHp041763; Fri, 11 Nov 2005 17:15:20 +0300 (MSK) (envelope-from glebius@FreeBSD.org) X-Authentication-Warning: cell.sick.ru: glebius set sender to glebius@FreeBSD.org using -f Date: Fri, 11 Nov 2005 17:15:19 +0300 From: Gleb Smirnoff To: Bruce M Simpson Message-ID: <20051111141519.GE1647@cell.sick.ru> References: <20051107140451.GU91530@cell.sick.ru> <20051111140926.GC733@empiric.icir.org> Mime-Version: 1.0 Content-Type: text/plain; charset=koi8-r Content-Disposition: inline In-Reply-To: <20051111140926.GC733@empiric.icir.org> User-Agent: Mutt/1.5.6i Cc: arch@FreeBSD.org Subject: Re: ARP request retransmitting X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 11 Nov 2005 14:15:24 -0000 On Fri, Nov 11, 2005 at 02:09:26PM +0000, Bruce M Simpson wrote: B> On Mon, Nov 07, 2005 at 05:04:51PM +0300, Gleb Smirnoff wrote: B> > I suggest to keep sending ARP requests while there is a demand for B> > this (we are trying to transmit packets to this particular IP), B> > ratelimiting these requests to one per second. This will help in a B> > quite common case, when some host on net is rebooting, and we are B> > waiting for him to come up, and notice this only after 1 - 20 seconds B> > since the time it is reachable. B> > Any objections? B> B> In response to the other replies to this thread citing broadcast B> pollution on Ethernet-based networks: B> Please add this functionality under a sysctl where it is turned off by default. B> B> It is desirable in situations where ARP entries cached further upstream are B> stale, but it may cause flooding in an environment where the layer 2 backbone B> hasn't been split or has not been segregated well. B> B> Other people cited examples where vendor switch implementations were B> retransmitting across VLANs -- this week I've been offering moral support B> to a friend who is dealing with similar VLAN brokenness at his $DAYJOB B> (there was an extension to 802.1d to support multiple spanning tree instances B> across VLANs which I think not everyone supports correctly). I'd like to see a proven evidence that this functionality leads to a measurable increase in broadcast traffic. Many modern operating systems behave in such way and no-one complains. The increase of broadcast traffic is very theoretical, it happens only when there are downed hosts. -- Totus tuus, Glebius. GLEBIUS-RIPN GLEB-RIPE