From owner-freebsd-net@FreeBSD.ORG Tue Mar 27 21:43:36 2007 Return-Path: X-Original-To: freebsd-net@freebsd.org Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id EA75E16A404 for ; Tue, 27 Mar 2007 21:43:36 +0000 (UTC) (envelope-from ml@netfence.it) Received: from parrot.aev.net (parrot.aev.net [212.31.247.179]) by mx1.freebsd.org (Postfix) with ESMTP id 1A90213C458 for ; Tue, 27 Mar 2007 21:43:33 +0000 (UTC) (envelope-from ml@netfence.it) Received: from soth.ventu ([151.77.236.62]) (authenticated bits=128) by parrot.aev.net (8.14.0/8.13.8) with ESMTP id l2RLNS6N052506 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Tue, 27 Mar 2007 23:23:34 +0200 (CEST) (envelope-from ml@netfence.it) Received: from [10.1.2.18] (alamar.ventu [10.1.2.18]) by soth.ventu (8.14.0/8.13.8) with ESMTP id l2RLFGqB026160; Tue, 27 Mar 2007 23:15:16 +0200 (CEST) (envelope-from ml@netfence.it) Message-ID: <46098962.3040707@netfence.it> Date: Tue, 27 Mar 2007 23:15:14 +0200 From: Andrea Venturoli User-Agent: Thunderbird 1.5.0.10 (X11/20070306) MIME-Version: 1.0 To: Jordan Gordeev References: <3DDDCC38D00FA545A6C012475EF2DC0302AF8F55@LQEVS1.gcapmedia.com> <46092E46.4090502@dir.bg> In-Reply-To: <46092E46.4090502@dir.bg> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.61 on 212.31.247.179 Cc: freebsd-net@freebsd.org, Ross Draper Subject: Re: Vrrp/CARP/ucarp Problems X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 27 Mar 2007 21:43:37 -0000 Jordan Gordeev wrote: > The only load balancing that CARP supports, to my knowledge, is ARP > level load balancing. From carp(4): > The ARP load balancing has some limitations. First, ARP balancing only > works on the local network segment. It cannot balance traffic that > crosses a router, because the router itself will always be balanced to > the same virtual host. Forgive me for stepping in, but I had read the above statement over and over trying to figure what it meant; perhaps it's not so clear... If I understood it correctly it's not saying you should not use CARP on routers. Instead it's meaning that load-balancing won't cross a third router which is on cascade of the two CARP routers. An image might help to clarify: +------+ +------+ +------+ .... +------+ |host I| |host J| |host K| .... |host Z| +------+ +------+ +------+ .... +------+ | | | | \--------+--------+-------------+---------\ | +------+ +------+ +------+ .... +------+ +--------+ |host A| |host B| |host C| .... |host H| |Router 3| +------+ +------+ +------+ .... +------+ +--------+ | | | | | \--------+-----+--+-------+-----+---------/ | | +--------+ +--------+ |Router 1| |Router 2| +--------+ +--------+ Suppose you are arp-balancing with CARP on Router 1 & 2, hosts A-H will get balanced, but hosts I-Z will all go to the same router (wether Router 1 or Router 2). This is because all their incoming packets will bear Router 3's MAC address. Is this interpretation correct? bye & Thanks av.