From owner-freebsd-arm@freebsd.org Fri Nov 11 01:49:44 2016 Return-Path: Delivered-To: freebsd-arm@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id E7DB1C3ADFB for ; Fri, 11 Nov 2016 01:49:44 +0000 (UTC) (envelope-from erichsfreebsdlist@alogt.com) Received: from alogt.com (alogt.com [69.36.191.58]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id C934AF43 for ; Fri, 11 Nov 2016 01:49:44 +0000 (UTC) (envelope-from erichsfreebsdlist@alogt.com) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=alogt.com; s=default; h=Content-Transfer-Encoding:Content-Type:MIME-Version:References: In-Reply-To:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=DeHODbLPoXynpo9HcLDC/FC0uc3AcWvbWQ1im3W0tzg=; b=ktEfpJvEDKTNL08h95ElIsUsdE EUXypriNiNnhdTRcTYfIw5Rn5PHHlg8fgd/32chDn5mUErPd9IIKMx6Zuc7ig4B6udnWuoxo6G/rR mMxMmPghcwsJGxEqYTF9dYZfsMSoUqWJCtrTP7oQSHlpxl5XWKtjPKbrip8GnDPMeXA0=; Received: from [114.125.84.199] (port=53635 helo=X220.alogt.com) by sl-508-2.slc.westdc.net with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.87) (envelope-from ) id 1c50yI-001UMq-5C; Thu, 10 Nov 2016 18:49:38 -0700 Date: Fri, 11 Nov 2016 09:49:30 +0800 From: Erich Dollansky To: "John W. Kitz" Cc: Subject: Re: How to change MAC address on RPI-B? Message-ID: <20161111094930.46f55a60@X220.alogt.com> In-Reply-To: <000c01d23b3a$c06e1ef0$414a5cd0$@Kitz@xs4all.nl> References: <005701d23a7d$71400630$53c01290$@Kitz@xs4all.nl> <20161110065105.77a19e3b@X220.alogt.com> <000c01d23b3a$c06e1ef0$414a5cd0$@Kitz@xs4all.nl> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - sl-508-2.slc.westdc.net X-AntiAbuse: Original Domain - freebsd.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - alogt.com X-Get-Message-Sender-Via: sl-508-2.slc.westdc.net: authenticated_id: erichsfreebsdlist@alogt.com X-Authenticated-Sender: sl-508-2.slc.westdc.net: erichsfreebsdlist@alogt.com X-Source: X-Source-Args: X-Source-Dir: X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "Porting FreeBSD to ARM processors." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 11 Nov 2016 01:49:45 -0000 Hi John, On Thu, 10 Nov 2016 11:11:02 +0100 "John W. Kitz" wrote: > > To the best of my recollection at the time there was no need > > whatsoever to configure these NICs into promiscuous mode, which in > > you need this for fault-tolerant computing. A machine or a device > with a known goes down, the failure will be detected and another > device or machine is configured to take over the other's task by also > taking over the other's MAC address. The communication partners will > only a delay but not a failure. > > JKi: I'm curious, would, in your experience, the impact of any delay > incurred by tinkering with addresses at both layer-3 AND layer-2 in a > failover situation be less in comparison to any delay incurred when > tinkering with the addresses at layer-3 ONLY and leave the recovery of > addressing issues at layer-2 to the relevant protocols? > it depends of what you want. When the machine connecting to the fault-tolerant machine is not fault-tolerant, it will not be able to change any addresses. All it will do is repeating requests. A watch-dog should have realised by then that either the interface or the machine with the interface is down and should have activated either a different interface or a different machine. It is just one of many option you have. And it is a cheap option as you can make even FreeBSD fault-tolerant with this as the operating system does not play any part in this kind of fault-tolerance. Erich