From owner-freebsd-audit Wed Jul 25 8:21:58 2001 Delivered-To: freebsd-audit@freebsd.org Received: from mail.chem.msu.ru (mail.chem.msu.ru [195.208.208.19]) by hub.freebsd.org (Postfix) with ESMTP id 8FFD537B91A for ; Wed, 25 Jul 2001 08:17:48 -0700 (PDT) (envelope-from yar@comp.chem.msu.su) Received: from comp.chem.msu.su ([158.250.32.97]) by mail.chem.msu.ru with SMTP (Microsoft Exchange Internet Mail Service Version 5.5.2650.21) id NHPRWACK; Wed, 25 Jul 2001 19:11:05 +0400 Received: (from yar@localhost) by comp.chem.msu.su (8.11.1/8.11.1) id f6PFHjs90467; Wed, 25 Jul 2001 19:17:45 +0400 (MSD) (envelope-from yar) Date: Wed, 25 Jul 2001 19:17:45 +0400 From: Yar Tikhiy To: audit@FreeBSD.ORG Cc: Dima Dorfman , Peter Jeremy Subject: Re: vlan(4) manpage Message-ID: <20010725191744.A77305@comp.chem.msu.su> References: <20010725072042.A24573@comp.chem.msu.su> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <20010725072042.A24573@comp.chem.msu.su>; from yar@FreeBSD.ORG on Wed, Jul 25, 2001 at 07:20:42AM +0400 Sender: owner-freebsd-audit@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG Hello, Thank Dima and Peter for your valuable comments. The next revision of the vlan(4) man page includes corrections and additions suggested by you. Moreover, I've added a paragraph on VLAN firmware support and written a whole subsection of tips on how to select and configure the right NIC to use with VLANs. -- Yar .\" .\" $FreeBSD$ .\" .Dd July 25, 2001 .Dt VLAN 4 .Os .Sh NAME .Nm vlan .Nd IEEE 802.1Q VLAN network interface .Sh SYNOPSIS .\" In -stable: .Cd pseudo-device vlan Op Ar count .Cd device vlan Op Ar count .\" .Sh DESCRIPTION The .Nm driver demultiplexes frames tagged according to the IEEE 802.1Q standard into logical .Nm network interfaces, which allows for routing/bridging between multiple VLANs through a single switch trunk port. .Pp To function, a .Nm interface must be assigned a parent interface and numeric VLAN tag using .Xr ifconfig 8 . A single parent can be assigned to multiple .Nm interfaces provided they have different tags. The parent interface is likely to be an ethernet one connected to a properly configured switch port. The VLAN tag should match one of those set up in the switched network. .Pp The .Nm driver supports physical devices that do the VLAN demultiplexing in firmware. The .Ar link0 flag should be set on a .Nm interface .Pq Em not on its parent using .Xr ifconfig 8 in that case to indicate that the hardware support for the 802.1Q VLANs is present in its parent. .\" .Ss "Selecting the right network interface card to run VLANs through" By now, the only NIC that has hardware support for the 802.1Q VLAN technology in FreeBSD is .Xr ti 4 . .Pp The rest of ethernet NICs supported by FreeBSD can run VLANs using the software emulation in the .Nm driver. However, most of them lack the capability of transmitting and/or receiving oversized frames. Using such a NIC as a parent interface for a .Nm implies a reduced MTU on the corresponding .Nm interfaces. In the modern Internet, the latter is likely to cause .Xr tcp 4 connectivity problems due to massive, inadequate .Xr icmp 4 filtering that breaks the Path MTU Discovery mechanism. .Pp The NICs that support oversized frames are as follows: .Bl -tag -width "fxp(4)" -compact -offset indent .It Xr de 4 requires defining .Dv BIG_PACKET in the .Pa /usr/src/sys/pci/if_de.c source file and rebuilding the kernel or the module. .It Xr fxp 4 supports oversized frames if both itself and the .Nm driver are compiled into the kernel, or if the .Dv FXP_FLAG_LONG_PKT_EN .Pq 0x20 device flag is set on it. .It Xr tl 4 may or may not work with the existing driver. .It Xr tx 4 may or may not work with the existing driver. .It Xr xl 4 works well only if the card has newer firmware .Pq 3c905C and above . .El .Sh SEE ALSO .Xr ifconfig 8 .Sh BUGS No 802.1Q features except VLAN tagging are implemented. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-audit" in the body of the message