From owner-freebsd-hackers Fri May 14 19:58:34 1999 Delivered-To: freebsd-hackers@freebsd.org Received: from allegro.lemis.com (allegro.lemis.com [192.109.197.134]) by hub.freebsd.org (Postfix) with ESMTP id 7C01D14C29 for ; Fri, 14 May 1999 19:58:29 -0700 (PDT) (envelope-from grog@freebie.lemis.com) Received: from freebie.lemis.com (freebie.lemis.com [192.109.197.137]) by allegro.lemis.com (8.9.1/8.9.0) with ESMTP id MAA16158; Sat, 15 May 1999 12:28:28 +0930 (CST) Received: (from grog@localhost) by freebie.lemis.com (8.9.3/8.9.0) id MAA48832; Sat, 15 May 1999 12:28:26 +0930 (CST) Date: Sat, 15 May 1999 12:28:26 +0930 From: Greg Lehey To: David Scheidt Cc: Dan Nelson , "Mark J. Taylor" , Daniel Eischen , freebsd-hackers@FreeBSD.ORG Subject: Re: ifconfig: changing mac address Message-ID: <19990515122826.O89091@freebie.lemis.com> References: <19990515121747.N89091@freebie.lemis.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.95.4i In-Reply-To: ; from David Scheidt on Fri, May 14, 1999 at 09:54:02PM -0500 WWW-Home-Page: http://www.lemis.com/~grog X-PGP-Fingerprint: 6B 7B C3 8C 61 CD 54 AF 13 24 52 F8 6D A4 95 EF Organization: LEMIS, PO Box 460, Echunga SA 5153, Australia Phone: +61-8-8388-8286 Fax: +61-8-8388-8725 Mobile: +61-41-739-7062 Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Friday, 14 May 1999 at 21:54:02 -0500, David Scheidt wrote: > On Sat, 15 May 1999, Greg Lehey wrote: > > : > :If you have two different nets, why do you need the same Ethernet > :address? > : > > Transparent redundancy. With them both up on the same MAC address, if one > fails, you have no loss of connection, though you may drop some packets, of > course. Most of the time you get twice the bandwidth. > > David, who doesn't want to think about writing a driver for this. OK, now maybe I'm missing something here. But an Ethernet address is used to identify a board. Arp binds it to an IP address. An IP address is bound to a network. So if you're on a different network, you get a different IP address. Why do you need the same Ethernet address? This is very different from having two boards on the same network, both with the same Ethernet address. As I observed earlier, that does make sense, but it's a hot standby situation. I can't see any point in arranging for both of them to accept or send data. Greg -- See complete headers for address, home page and phone numbers finger grog@lemis.com for PGP public key To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message