Return-Path: Received: from sc1.scconsult.com ([66.73.230.190] verified) by mail.stalker.com (CommuniGate Pro SMTP 4.2.7) with SMTP id 30946489 for SIMS@mail.stalker.com; Wed, 01 Dec 2004 20:15:56 -0800 Received-SPF: pass receiver=mail.stalker.com; client-ip=66.73.230.190; envelope-from=listbill@scconsult.com Received: from [192.168.254.128] ([192.168.254.128] verified) by sc1.scconsult.com (Stalker SMTP Server 1.8b9d14) with ESMTP id S.0000716416 for ; Wed, 01 Dec 2004 23:15:39 -0500 Mime-Version: 1.0 Message-Id: In-Reply-To: References: Date: Wed, 1 Dec 2004 23:15:30 -0500 To: "SIMS Discussions" From: Bill Cole Subject: Re: Wandering off-topic: Speedstream 5861 (was Re: Authentication Attempts) Content-Type: text/plain; charset="us-ascii" ; format="flowed" At 10:53 PM -0500 12/1/04, Alex von Thorn imposed structure on a stream of electrons, yielding: >No, Ethernet is a layer-two protocol, DSL is a layer-one protocol. A >DSL modem modulates and demodulates a DSL signal (hence the name >"modem") to another data link protocol (commonly but not necessarily >Ethernet). Physical protocols are about signalling and electrical >signals which form bits on a physical medium; data link protocols >group bits together into bytes and frames, over any physical medium. >DSL commonly uses Ethernet because home computers have Ethernet >ports and DSL modems often act simply as an Ethernet bridge with no >network routing function. Theoretically, one could use DSL to carry >PPP (though that would be very odd), ATM, frame relay, MPLS, or >whatever. FWIW, SBC (one of the largest DSL providers) in most areas layers ATM over DSL and PPP over the ATM virtual circuit to get the IP layer up. That is a reasonably common approach, as it has some provider-side advantages over making the intrinsically point-to-point DSL look like an Ethernet and then running DHCP over it. -- Bill Cole bill@scconsult.com