From owner-freebsd-net Wed Mar 24 13:14:43 1999 Delivered-To: freebsd-net@freebsd.org Received: from xylan.com (postal.xylan.com [208.8.0.248]) by hub.freebsd.org (Postfix) with ESMTP id E955A14FAE for ; Wed, 24 Mar 1999 13:14:39 -0800 (PST) (envelope-from wes@softweyr.com) Received: from mailhub.xylan.com by xylan.com (8.8.7/SMI-SVR4 (xylan-mgw 2.2 [OUT])) id NAA00805; Wed, 24 Mar 1999 13:12:31 -0800 (PST) Received: from utah.XYLAN.COM by mailhub.xylan.com (SMI-8.6/SMI-SVR4 (mailhub 2.1 [HUB])) id NAA18492; Wed, 24 Mar 1999 13:12:30 -0800 Received: from softweyr.com by utah.XYLAN.COM (SMI-8.6/SMI-SVR4 (xylan utah [SPOOL])) id OAA07619; Wed, 24 Mar 1999 14:12:21 -0700 Message-ID: <36F95545.6B1F40C0@softweyr.com> Date: Wed, 24 Mar 1999 14:12:37 -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: Petri Helenius Cc: Bill Fumerola , Peter Brezny , freebsd-net@FreeBSD.ORG Subject: Re: switch vs bridge (fwd) References: <36F95064.670D0DA1@sms.fi> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org Petri Helenius wrote: > > Bill Fumerola wrote: > > > > On Wed, 24 Mar 1999, Petri Helenius wrote: > > > > > > A switch replicates packets based on their Ethernet destination. > > > > > > > And how exactly would you describe a bridge then? > > > > Anything I say is going to be able to be picked apart, > > > > but a bridge replicates any data it sees for its destination network and > > just shoves it over. > > > > A switch makes an intelligent port-by-port decision. > > > 99% of ethernet bridges out there have a forwarding table as the switches > have which are multiport bridges. It's a completely different ballgame for > token ring though. > > There is no concept of "network" in ethernet so you cannot do any actions > based on the addressing other than learn where all the sources are. This > process > is equally the same for bridges and switches. (since they are the same) Try these on for size: MAC-Layer Bridge - A device used to forward data between LANs at layer two, by automatically filtering out traffic which is local to each LAN, while forwarding on traffic which is not local to each LAN. All broadcasts and multicasts, as well as all traffic with a destination address which has not been learned by the bridge, is forwarded. MAC-Layer Switching - LAN data transferred through a network based on the source and destination address contained in the MAC header of the frame. Essentially the same as bridging, but almost always employing dedicated hardware to perform the switching. In other words, there isn't a whole lot of difference unless you step up to layer three switches. These definitions taken from "The Switching Book II", from Xylan Corp. Download a PDF version or order your own free printed copy at: http://www.xylan.com/library/switchbook/index.html While you're there, poke around and buy something. ;^) -- Where am I, and what am I doing in this handbasket? Wes Peters +1.801.915.2061 Softweyr LLC wes@softweyr.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message