From owner-freebsd-hackers Wed Oct 7 17:10:44 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id RAA29868 for freebsd-hackers-outgoing; Wed, 7 Oct 1998 17:10:44 -0700 (PDT) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from dingo.cdrom.com (dingo.cdrom.com [204.216.28.145]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id RAA29853 for ; Wed, 7 Oct 1998 17:10:38 -0700 (PDT) (envelope-from mike@dingo.cdrom.com) Received: from dingo.cdrom.com (localhost.cdrom.com [127.0.0.1]) by dingo.cdrom.com (8.9.1/8.8.8) with ESMTP id RAA03646; Wed, 7 Oct 1998 17:15:50 -0700 (PDT) (envelope-from mike@dingo.cdrom.com) Message-Id: <199810080015.RAA03646@dingo.cdrom.com> X-Mailer: exmh version 2.0.2 2/24/98 To: Archie Cobbs cc: hackers@FreeBSD.ORG Subject: Re: How to send data between two network cards directly? In-reply-to: Your message of "Wed, 07 Oct 1998 17:01:28 PDT." <199810080001.RAA23283@bubba.whistle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Wed, 07 Oct 1998 17:15:50 -0700 From: Mike Smith Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > Mike Smith writes: > > > > > I have two machines connected with two network cards directly > > > > > together via 10Base2. I would like to send data from one > > > > > machine two the other without doing IP or any other > > > > > protocol. > > > > > > > > You have to have some protocol, or you can't tell what any given item > > > > of data is. > > > > > > OK, maybe I desribed it in a wrong way. I would like to use > > > the most basic protocol that is available. No overhead, > > > no error correction, no nothing... > > > > You can't do this. Ethernet implicitly involves several protocols, > > each with their own overheads and error correction. > > Not true.. Ethernet is just synchronous HDLC with a 32 bit checksum. > You can send and receive raw Ethernet frames using bpf(4). I see at least two there; the Ethernet protocol (implemented substantially in hardware) and the interface to the Ethernet card. Anyway, my response was to the "no overhead, no error correction, no nothing". Ethernet has mandatory overhead, mandatory (usually hardware) error detection, and no "no nothing". I think I was right. 8) -- \\ Sometimes you're ahead, \\ Mike Smith \\ sometimes you're behind. \\ mike@smith.net.au \\ The race is long, and in the \\ msmith@freebsd.org \\ end it's only with yourself. \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message