2001-09-11 21:54:20 +04:00
|
|
|
.\" $NetBSD: bridge.4,v 1.2 2001/09/11 17:54:20 wiz Exp $
|
2001-08-18 02:20:34 +04:00
|
|
|
.\"
|
|
|
|
|
.\" Copyright 2001 Wasabi Systems, Inc.
|
|
|
|
|
.\" All rights reserved.
|
|
|
|
|
.\"
|
|
|
|
|
.\" Written by Jason R. Thorpe for Wasabi Systems, Inc.
|
|
|
|
|
.\"
|
|
|
|
|
.\" 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.
|
|
|
|
|
.\" 3. All advertising materials mentioning features or use of this software
|
|
|
|
|
.\" must display the following acknowledgement:
|
|
|
|
|
.\" This product includes software developed for the NetBSD Project by
|
|
|
|
|
.\" Wasabi Systems, Inc.
|
|
|
|
|
.\" 4. The name of Wasabi Systems, Inc. may not be used to endorse
|
|
|
|
|
.\" or promote products derived from this software without specific prior
|
|
|
|
|
.\" written permission.
|
|
|
|
|
.\"
|
|
|
|
|
.\" THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``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 WASABI SYSTEMS, INC
|
|
|
|
|
.\" 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.
|
2001-09-11 21:54:20 +04:00
|
|
|
.\"
|
2001-08-18 02:20:34 +04:00
|
|
|
.Dd August 17, 2001
|
|
|
|
|
.Dt BRIDGE 4
|
|
|
|
|
.Os
|
|
|
|
|
.Sh NAME
|
|
|
|
|
.Nm bridge
|
|
|
|
|
.Nd network bridge device
|
|
|
|
|
.Sh SYNOPSIS
|
|
|
|
|
.Cd "pseudo-device bridge"
|
|
|
|
|
.Sh DESCRIPTION
|
|
|
|
|
The
|
|
|
|
|
.Nm
|
|
|
|
|
driver creates a logical link between two or more IEEE 802 networks
|
|
|
|
|
that use the same (or
|
|
|
|
|
.Dq similar enough )
|
|
|
|
|
framing format. For example, it is possible to bridge Ethernet and
|
|
|
|
|
802.11 networks together, but it is not possible to bridge Ethernet
|
|
|
|
|
and Token Ring together.
|
|
|
|
|
.Pp
|
|
|
|
|
To use
|
|
|
|
|
.Nm bridge ,
|
|
|
|
|
the administrator must first create the interface and configure
|
|
|
|
|
the bridge parameters. The bridge is created using the
|
|
|
|
|
.Xr ifconfig 8
|
|
|
|
|
.Sq create
|
|
|
|
|
subcommand.
|
|
|
|
|
The learning and forwarding behavior and other parameters of a
|
|
|
|
|
bridge are configured by the
|
|
|
|
|
.Xr brconfig 8
|
|
|
|
|
utility.
|
|
|
|
|
.Pp
|
|
|
|
|
A bridge can be used to provide several services, such as a simple
|
|
|
|
|
802.11-to-Ethernet bridge for wireless hosts, and traffic isolation.
|
|
|
|
|
.Pp
|
|
|
|
|
A bridge works like a hub, forwarding traffic from one interface
|
|
|
|
|
to another. Multicast and broadcast packets are always forwarded
|
|
|
|
|
to all interfaces that are part of the bridge. For unicast traffic,
|
|
|
|
|
the bridge learns which MAC addresses are associated with which segments
|
|
|
|
|
will forward the traffic selectively.
|
|
|
|
|
.Pp
|
|
|
|
|
The
|
|
|
|
|
.Nm
|
|
|
|
|
driver implements the IEEE 802.1D Spanning Tree protocol (STP). Spanning
|
|
|
|
|
Tree is used to detect and remove loops in a network topology.
|
2001-09-11 21:54:20 +04:00
|
|
|
.Sh HISTORY
|
|
|
|
|
The
|
|
|
|
|
.Nm
|
|
|
|
|
driver first appeared in
|
|
|
|
|
.Nx 1.6 .
|
2001-08-18 02:20:34 +04:00
|
|
|
.Sh AUTHORS
|
|
|
|
|
The
|
|
|
|
|
.Nm bridge
|
|
|
|
|
driver was originally written by
|
|
|
|
|
.An Jason L. Wright
|
|
|
|
|
.Aq jason@thought.net
|
|
|
|
|
as part of an undergraduate independent study at the University of
|
|
|
|
|
North Carolina at Greensboro.
|
|
|
|
|
.Pp
|
|
|
|
|
This version of the
|
|
|
|
|
.Nm
|
|
|
|
|
driver has been heavily modified from the original version by
|
|
|
|
|
.An Jason R. Thorpe
|
|
|
|
|
.Aq thorpej@wasabisystems.com .
|
|
|
|
|
.Sh BUGS
|
|
|
|
|
The
|
|
|
|
|
.Nm
|
|
|
|
|
driver currently supports only Ethernet and Ethernet-like (e.g. 802.11)
|
|
|
|
|
network devices.
|
|
|
|
|
.Pp
|
|
|
|
|
The
|
|
|
|
|
.Nm
|
|
|
|
|
driver currently does not support snooping via
|
|
|
|
|
.Xr bpf 4
|
|
|
|
|
or transparent filtering.
|
