From owner-freebsd-arch@FreeBSD.ORG Mon Nov 7 15:19:30 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 40B9B16A41F; Mon, 7 Nov 2005 15:19:30 +0000 (GMT) (envelope-from bv@bilver.wjv.com) Received: from wjv.com (fl-65-40-24-38.sta.sprint-hsd.net [65.40.24.38]) by mx1.FreeBSD.org (Postfix) with ESMTP id 9AC0A43D45; Mon, 7 Nov 2005 15:19:29 +0000 (GMT) (envelope-from bv@bilver.wjv.com) Received: from bilver.wjv.com (localhost.wjv.com [127.0.0.1]) by wjv.com (8.13.5/8.13.1) with ESMTP id jA7FJRgo006891; Mon, 7 Nov 2005 10:19:27 -0500 (EST) (envelope-from bv@bilver.wjv.com) Received: (from bv@localhost) by bilver.wjv.com (8.13.5/8.13.1/Submit) id jA7FJRkB006890; Mon, 7 Nov 2005 10:19:27 -0500 (EST) (envelope-from bv) Date: Mon, 7 Nov 2005 10:19:27 -0500 From: Bill Vermillion To: Gleb Smirnoff Message-ID: <20051107151927.GD1830@wjv.com> References: <20051107140451.GU91530@cell.sick.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20051107140451.GU91530@cell.sick.ru> Organization: W.J.Vermillion / Orlando - Winter Park ReplyTo: bv@wjv.com User-Agent: Mutt/1.5.11 X-Spam-Status: No, score=-1.4 required=5.0 tests=ALL_TRUSTED autolearn=failed version=3.1.0 X-Spam-Checker-Version: SpamAssassin 3.1.0 (2005-09-13) on bilver.wjv.com Cc: arch@freebsd.org Subject: Re: ARP request retransmitting X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: bv@wjv.com List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 07 Nov 2005 15:19:30 -0000 On Mon, Nov 07, 2005 at 17:04 , the primordial soup was bombarded with cosmic radiation and a new life form of genus Gleb Smirnoff emerged to test its air breathing capabilities and with great effort gasped: > Colleagues, > I have a proposition on changing the behavior of ARP retransmitting. > Currently we after sending several ARP requests, sending ARP requests > for given IP is suppressed for some interval (by default 20 seconds). > Probably this feature was designed in early 90th, when sending one > additional broadcast packet was an expensive thing. The man page says the host is considered down "for a short period (normally 20 seconds), allowing an error to be returned to transmission attempts in this interval". > I suggest to keep sending ARP requests while there is a demand for > this (we are trying to transmit packets to this particular IP), > ratelimiting these requests to one per second. This will help in a > quite common case, when some host on net is rebooting, and we are > waiting for him to come up, and notice this only after 1 - 20 seconds > since the time it is reachable. > Any objections? Is the 20 second limit that much of a problem. And the 20 minute timeout for caching is certainly far more generous that my old big Cisco that had a 4 hour cache. A user complained that he put up new machines and things weren't working. I told him he should have called me before he put the IPs back the way they were as cleanring the arp-cache took care of that. How big is your network? Bill -- Bill Vermillion - bv @ wjv . com