From owner-freebsd-net Sat Mar 27 7:14:17 1999 Delivered-To: freebsd-net@freebsd.org Received: from obie.softweyr.com (unknown [204.68.178.33]) by hub.freebsd.org (Postfix) with ESMTP id 610D714F4F for ; Sat, 27 Mar 1999 07:14:14 -0800 (PST) (envelope-from wes@softweyr.com) Received: from softweyr.com (wes@zaphod.softweyr.com [204.68.178.35]) by obie.softweyr.com (8.8.8/8.8.8) with ESMTP id IAA01522; Sat, 27 Mar 1999 08:13:38 -0700 (MST) (envelope-from wes@softweyr.com) Message-ID: <36FCF5A2.8F3F11E9@softweyr.com> Date: Sat, 27 Mar 1999 08:13:38 -0700 From: Wes Peters Organization: Softweyr llc X-Mailer: Mozilla 4.5 [en] (X11; U; FreeBSD 3.1-RELEASE i386) X-Accept-Language: en MIME-Version: 1.0 To: Mike Jenkins Cc: freebsd-net@freebsd.org, mm@i.cz Subject: Re: switch vs bridge (fwd) References: <199903270149.TAA07234@carp.gbr.epa.gov> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org Mike Jenkins wrote: > > Wes Peters wrote: > > The you either don't understand the job, or don't understand the (very > > limited) capabilities of these so-called layer 4 switches. It's not that > > it's a bad idea, just that there are a couple of vendors out there giving > > the idea a bad name with their implementations. > > I think the concept of switching based on udp/tcp port is useful. > One thing I'm not clear on is at what layer is the switch gathering > the packets? Is it at the data link (Ethernet) layer or the network > layer (IP)? I was assuming the data link layer to allow transparency. > If it is the network layer then the switch is your router as Wes said. > Do layer 3 switches have the ability to redirect packets based on > udp/tcp port numbers? That is, by definition, layer 4. Layer 3 is the IP address layer, and no "port" information occurs there. As I said above, it's not that layer 4 switching is a bad idea, it's just that the current implementation from some of these vendors is a bit weak, and none are based on standard protocols. And it *is* a bad idea to have every switch on your network peeking all the way into the layer 4 information of EVERY packet flowing through, that means you've bought a couple thousand times more packet processing power than you really need. The best way to do it would be to stick a layer-4 balancing engine inside a switch chassis, managing ports via the switch backplane. AFAIK nobody has done this yet, but it's such a darned good idea, I know somebody who might. ;^) -- "Where am I, and what am I doing in this handbasket?" Wes Peters Softweyr LLC http://www.softweyr.com/~softweyr wes@softweyr.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message