Finally add the manpage for the IEEE 802.1Q VLAN

network interface.

1 files changed, 143 insertions, 0 deletions

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+.\"
+.\" Copyright (c) 2001 Yar Tikhiy
+.\" All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\" $FreeBSD$
+.\"
+.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 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 card 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 NICs that have both hardware support and proper
+driver hooks for the 802.1Q VLAN technology in
+.Fx
+are
+.Xr nge 4 ,
+.Xr ti 4 ,
+and
+.\" not in -stable
+.Xr txp 4 .
+.Pp
+The rest of the ethernet NICs supported by
+.Fx
+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, this 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
+.\" not in -stable
+or module.
+The hack works only for the 21041, 21140, and 21140A chips.
+.It Xr fxp 4
+supports long frames for the
+.Nm
+natively.
+.It Xr tl 4
+does support long frames.
+.It Xr tx 4
+may begin supporting long frames soon.
+.It Xr xl 4
+supports long frames only if the card is built on a newer chip
+.Pq Cyclone and above .
+.El
+Note:
+Except for
+.Xr fxp 4 ,
+none of the above drivers inform the
+.Nm
+driver about their support for long frames.
+Just fix the MTU of a
+.Nm
+interface if it appears to be lower that 1500 bytes after
+attaching the
+.Nm
+to a parent interface that is known to support long frames.
+.Sh SEE ALSO
+.Xr ifconfig 8
+.Sh BUGS
+No 802.1Q features except VLAN tagging are implemented.