Date: Thu, 08 Oct 1998 09:22:36 +0200 From: sthaug@nethelp.no To: archie@whistle.com Cc: mike@smith.net.au, andre.albsmeier@mchp.siemens.de, hackers@FreeBSD.ORG Subject: Re: How to send data between two network cards directly? Message-ID: <29258.907831356@verdi.nethelp.no> In-Reply-To: Your message of "Wed, 7 Oct 1998 17:01:28 -0700 (PDT)" References: <199810080001.RAA23283@bubba.whistle.com>
next in thread | previous in thread | raw e-mail | index | archive | help
> > 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). This may be splitting hairs, but: 10 Mbps Ethernet is *not* like synchronous HDLC, because it has a "start bit" (the preamble). 100 Mbps Ethernet is different - this is more like a synchronous serial line in that there's signal on the cable at all times. Also, half duplex Ethernet uses CSMA/CD, which is definitely what I would call a protocol (implemented in hardware). Steinar Haug, Nethelp consulting, sthaug@nethelp.no To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?29258.907831356>