From owner-freebsd-net Thu Apr 5 12:16:30 2001 Delivered-To: freebsd-net@freebsd.org Received: from whizzo.transsys.com (whizzo.TransSys.COM [144.202.42.10]) by hub.freebsd.org (Postfix) with ESMTP id DF73137B42C for ; Thu, 5 Apr 2001 12:16:27 -0700 (PDT) (envelope-from louie@whizzo.transsys.com) Received: from whizzo.transsys.com (localhost.transsys.com [127.0.0.1]) by whizzo.transsys.com (8.11.3/8.11.0) with ESMTP id f35JG5n54176; Thu, 5 Apr 2001 15:16:24 -0400 (EDT) (envelope-from louie@whizzo.transsys.com) Message-Id: <200104051916.f35JG5n54176@whizzo.transsys.com> X-Mailer: exmh version 2.3.1 01/18/2001 with nmh-1.0.4 Cc: Wes Peters , Brett Glass , freebsd-net@FreeBSD.ORG X-Image-URL: http://www.transsys.com/louie/images/louie-mail.jpg From: "Louis A. Mamakos" Subject: Re: Transition from modem PPP to PPPoE References: <4.3.2.7.2.20010330201802.00dc8f00@localhost> <4.3.2.7.2.20010401141552.0452a6c0@localhost> <3ACBF0B6.52B99863@softweyr.com> <200104051738.f35Hcsn53390@whizzo.transsys.com> In-reply-to: Your message of "Thu, 05 Apr 2001 13:38:54 EDT." <200104051738.f35Hcsn53390@whizzo.transsys.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Thu, 05 Apr 2001 15:16:05 -0400 Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org > I've never thought that the 4 bytes of overhead per PPPoE frame was > terribly inefficient, compared to, say, IP-in-IP with another 20 byte > IP header. But I'm certainly not arguing that a choice of technology > be made on simply the number of bytes on the wire; there are other > things to consider as well. Ooops, must have been smoking some of Jordan's crack. That's more like 14 bytes rather than 4. Still, we're in the same ballpark at other schemes of tunneling over ethernet. I think that the code path-length might be a bit longer for PPPoE, but that's a wild-ass guess. I have a suspicion that there's slightly more overhead paid for the netgraph-based implementation as compared to a optimally coded IP-in-IP tunnel (using gif?). Of course, the netgraph implementation is a huge win over running the packets up into user mode and doing a context switch. louie To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message