From owner-freebsd-net Sun Oct 27 1: 6:20 2002 Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 4E96337B401 for ; Sun, 27 Oct 2002 01:06:19 -0800 (PST) Received: from pursued-with.net (adsl-66-125-9-242.dsl.sndg02.pacbell.net [66.125.9.242]) by mx1.FreeBSD.org (Postfix) with ESMTP id BD3B643E6A for ; Sun, 27 Oct 2002 01:06:13 -0800 (PST) (envelope-from Kevin_Stevens@pursued-with.net) Received: from pursued-with.net (fffinch [192.168.168.101]) by pursued-with.net (8.12.6/8.12.5) with ESMTP id g9R95fsG002190; Sun, 27 Oct 2002 01:05:41 -0800 (PST) (envelope-from Kevin_Stevens@pursued-with.net) Date: Sun, 27 Oct 2002 01:05:41 -0800 Subject: Dual Networks - Was: Annoying ARP warning messages. Content-Type: text/plain; charset=US-ASCII; format=flowed Mime-Version: 1.0 (Apple Message framework v546) Cc: freebsd-net@FreeBSD.ORG To: Julian Elischer From: Kevin Stevens In-Reply-To: Message-Id: <44E18C9B-E98B-11D6-BF1E-003065715DA8@pursued-with.net> Content-Transfer-Encoding: 7bit X-Mailer: Apple Mail (2.546) Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org On Saturday, Oct 26, 2002, at 23:42 US/Pacific, Julian Elischer wrote: > As one of the people whio wrote lots of the code you are using I'm > trying to figure out why you are doing something that we never > designed it to do because "no-one would want to do that". > i.e. "Do we have to change any design criteria? > Is there soemm reason that this is suddenly something people will want > to do?" Well, speaking generally, here are some of the reasons I've seen people run two NICS on the same physical network: - Redundancy for NIC failure. This is often combined with a second physical layer network, but that's not always feasible. - Configuration requirements. Sometimes there are compatibility issues associated with running multiple protocols on the same card, sometimes there are configuration differences. For example, one might want to run jumbo frames on a gig card to connect to a backup server, but need to limit MTU on connections headed to the outside world via external VPN. You can't always do what you need to with aliases on a single card. - Traffic control/accounting. Statistics and SNMP counters usually run against the physical interface rather than the IP address, so if you need accounting for separate networks (for utilization reports, billing, etc.) it can be desirable to have multiple NICS in the same box. - Load balancing/teaming. Via MLPPP or other teaming technology, you might have several 100MB connections teamed out of the same box to a switch with a faster uplink to the destination. The ARP issue mentioned will still occur even though each NIC has it's own dedicated 100MB duplex connection. I'm sure there are others out there as well. KeS To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message