Date: Tue, 03 Aug 1999 09:45:17 -0400 From: "Louis A. Mamakos" <louie@TransSys.COM> To: Brian Somers <brian@FreeBSD.org.uk> Cc: jonathan michaels <jon@caamora.com.au>, Brian Somers <brian@Awfulhak.org>, Robert Watson <robert+freebsd@cyrus.watson.org>, freebsd-net@FreeBSD.ORG Subject: Re: "Invitation to participate in PPPoE Trial" (fwd) Message-ID: <199908031345.JAA09965@whizzo.transsys.com> In-Reply-To: Your message of "Tue, 03 Aug 1999 14:21:54 BST." <199908031321.OAA07776@keep.lan.Awfulhak.org> References: <199908031321.OAA07776@keep.lan.Awfulhak.org>
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> Personally, I prefer the idea of having something like PPPoUDP > instead. This would provide all the same facilities, be very easy to > implement (user-ppp can do it already!) and would be routable, all > for a very small encapsulation overhead. This already exists; it's called L2TP. One of the desires for PPPoE was that an ISP could install a *DSL connection to a customer, and use Ethernet as the medium between the DSL "modem" CPE device and your PC(s). Using something like L2TP would require that the DSL "modem" device either: - be configured with an address that "works" on your ethernet segment - acts as a DHCP server and tells the other devices on the LAN what their IP addresses need to be. The first alterantive means a higher customer support cost - more configuration knows that will be set wrong. The second alternative means you break whatever existing LAN stuff is going on. So PPPoE runs over "raw" Ethernet MAC frames to get across the LAN from the PC to the DSL modem. There's no configuration of the CPE device, so it's hard to get the knobs set wrong. This aspect is of serious concern because DSL services are fairly low margin, and you can't afford to have a guy (or two!) in truck go around to every customer to turn on the service, or many suppport phone calls. You have to keep in the back of your mind that there are legions of consumer/residential Windows users that are the primary audience for this technology, and the associated support and operation costs of running this kind of network are always of concern. This is the whole reason for ADSL "lite" (Or "G.lite") - it's not supposed to require a "splitter" at the subscriber premisis, so the desperate hope is that the service can be turned up on your existing POTS phone line with no one making a service call to "install" the service at your residence. "Normal" ADSL requires a splitter to be installed because the ADSL modulation can be heard as noise in analog phone sets, and you'd also like to isolate the POTS phones when the go off-hook and change the loading characteristics on the line. Note that if someone did L2TP over raw ethernet, it would be more or less equivilent; it's just that when we had the need, L2TP over IP wasn't even done yet (and still isn't, really) much less trying to extend it. louie (one of the authors of the PPPoE protocol/RFC) To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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