Date: Thu, 01 Oct 1998 00:29:32 +0930 From: Leigh Hart <hart@dotat.com> To: freebsd-net@FreeBSD.ORG, freebsd-hackers@FreeBSD.ORG Subject: 802.1Q VLAN support Message-ID: <199809301459.AAA15771@at.dotat.com>
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I'm developing some single board computer applications that require 802.1Q vlan support (of the simplest kind) and in trawling through these list archives I found mention of if_vlan.c ...: /* * ... * ... * ... * * $Id: if_vlan.c,v 1.3 1998/08/23 03:07:10 wollman Exp $ */ /* * if_vlan.c - pseudo-device driver for IEEE 802.1Q virtual LANs. * Might be extended some day to also handle IEEE 802.1p priority * tagging. This is sort of sneaky in the implementation, since * we need to pretend to be enough of an Ethernet implementation * to make arp work. The way we do this is by telling everyone * that we are an Ethernet, and then catch the packets that * ether_output() left on our output queue queue when it calls * if_start(), rewrite them for use by the real outgoing interface, * and ask it to send them. */ This is about all I can find in the kernel-current source tree that relates to 802.1Q - there's little or no documentation I can find that tells me how to start using this code...(god help me if it's there and I havn't looked hard enough :[) Any pointers to /dev/obvious gratefully accepted... PS - my work with 802.1Q has found that, despite the current draft spec suggesting that each vendor should decide on their own what to do about the problem of having a larger frame size due to the extra 4 byte VLAN header, most vendors have opted to support an increas by four bytes in the frame size... It should be noted that if FreeBSD is going to support this in any sensible manner, it should start including an option for changing ETHER_MAX_LEN in the kernel, either real time or at compile time... Cheers Leigh -- | "By the time they had diminished | Leigh Hart, <hart@dotat.com> | | from 50 to 8, the other dwarves | Dotat Communications Pty Ltd | | began to suspect 'Hungry' ..." | GPO Box 487 Adelaide SA 5001 | | -- Gary Larson, "The Far Side" | http://www.dotat.com/hart/ | To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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