255 lines
6.0 KiB
Groff
255 lines
6.0 KiB
Groff
.\" $NetBSD: strip.4,v 1.7 1999/03/16 01:19:18 garbled Exp $
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.\"
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.\" Copyright 1996 The Board of Trustees of The Leland Stanford
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.\" Junior University. All Rights Reserved.
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.\"
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.\" Author: Jonathan Stone
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.\"
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.\" Permission to use, copy, modify, and distribute this
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.\" software and its documentation for any purpose and without
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.\" fee is hereby granted, provided that the above copyright
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.\" notice and the above authorship notice appear in all copies.
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.\" Stanford University makes no representations about the suitability
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.\" of this software for any purpose. It is provided "as is" without
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.\" express or implied warranty.
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.Dd March 10, 1996
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.Dt STRIP 4
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.Os
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.Sh NAME
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.Nm strip
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.Nd network driver for the Metricom Ricochet packet radio
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.Sh SYNOPSIS
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.Cd pseudo-device strip Op Ar count
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.Sh DESCRIPTION
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Configures
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.Ar count
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.Nm
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interfaces, named
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.Em strip0 ,
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.Em strip1 ,
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etc, into a
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.Nx
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kernel built from a
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.Xr config 8
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file containing the given entry.
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.Pp
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Each
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.Nm
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interface is a pseudo-device driver for the
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.Tn Metricom
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.Em Ricochet
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packet radio, operating in peer-to-peer packet mode.
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.Pp
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The
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.Nm
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driver takes outbound network packets, encapsulates them using the
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.Tn Metricom
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.Qq star mode
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framing, and sends the packets out an
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.Tn RS-232
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interface to a
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.Tn Metricom
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.Em Ricochet
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packet radio.
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Packets arriving from the packet radio via the serial link are decapsulated
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and then passed up to the local host's networking stack.
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.Pp
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.Nm
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is an acronym for
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.Sy ST Ns armode
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.Sy R Ns adio
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.Sy IP.
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.Pp
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In many ways,
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the
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.Nm
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driver is very much like the
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.Xr sl 4
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SLIP pseudo-device driver.
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A
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.Nm
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device is attached to a tty line with
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.Xr slattach 8 .
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Once attached, the interface is configured via
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.Xr ifconfig 8 .
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The major difference between the
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.Xr sl 4
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SLIP pseudo-device driver and the
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.Nm
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driver is that SLIP works only between two hosts over
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a dedicated point-to-point connection.
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.Pp
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In contrast,
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.Nm
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sends packets to a frequency-hopping packet radio, which can address
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packets to any peer
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.Tn Metricom
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.Em Ricochet
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packet radio, rather than just to a single host at the other end
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of a point-to-point line.
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Thus, one
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.Nm
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pseudo-device is usually sufficient for any kernel.
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.Pp
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In other respects, a
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.Nm
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interface is rather like an
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.Tn Ethernet
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interface.
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Packets are individually addressed, and subsequent packets can
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be sent independently to different MAC addresses.
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However, the
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.Qq star mode
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framing and MAC addressing are not in any way compatible with
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.Tn Ethernet .
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Broadcast or multicast to more than one packet radio is not possible,
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due to the independent frequency-hopping operation of the packet radios.
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The interface flags
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.Dv IFF_POINTOPOINT
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and
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.Dv IFF_BROADCAST
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are not supported on the
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.Nm
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interface.
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.Pp
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In other words,
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.Nm
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implements a multiple-access, non-broadcast device, accessed via
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an RS-232 serial line, using a proprietary packet framing scheme.
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.Pp
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This version of the
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.Nm
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driver maps
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.Tn IP
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addresses to
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.Tn Metricom
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.Em Ricochet
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packet radio addresses using statically configured entries in the
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normal routing table.
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These entries map
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.Tn IP
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addresses of peer packet radios to the MAC-level addresses.
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The exact syntax of this mapping and an example are discussed below.
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The Internet Assigned Numbers Authority
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.Pq Tn IANA
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has allocated an
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.Tn ARP
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type code for use with STRIP.
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A future version of this driver will support
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.Xr arp 4
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to obtain the
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.Tn IP
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address of reachable peer packet radios dynamically.
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.Pp
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.Sh ADDRESS CONFIGURATION
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This version of the STRIP driver requires static pre-configuration of
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the mapping from
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.Tn IP
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addresses to packet radio MAC addresses.
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The
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.Xr route 8
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command should be used to bind a peer STRIP host's packet radio
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.Tn IP
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address to the peer's link-level packet radio address.
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.Pp
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Radio addresses are encoded using the hex equivalent of the packet
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radio's decimal
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.Tn ASCII
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address.
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For example, the following route command will configure a routing
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entry to a packet radio with a MAC address of 1234-5678, and an
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.Tn IP
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address 10.11.12.13, reachable via the
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.Em strip0
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interface:
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.Pp
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.br
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.in 10
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route add -host 10.11.12.13 -link strip0:1:2:3:4:5:6:7:8
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.br
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.in 5
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.Pp
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Generalising from this example to other
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.Tn IP
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addresses and to other 8-digit MAC addreses should be clear.
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.Pp
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.Sh RADIO CONFIGURATION
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The
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.Tn Metricom
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.Em Ricochet
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packet radios can auto-baud at speeds up to 38.4K baud.
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At higher speeds -- 57600 or 115200 -- the packet radio cannot autobaud.
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When running at high speeds, the packet radio's serial port should be
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manually configured to permanently run at the desired speed.
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Use a terminal emulator and the Hayes command
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.Ic ATS304=115200
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to set the serial baudrate to the specified number (or 0 for autobaud).
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The command
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.Ic AT&W
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will then save the current packet radio state in non-volatile memory.
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.Pp
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.Tn Metricom
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.Em Ricochet
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packet radios can operate in either
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.Dq modem-emulation
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mode or in packet mode (i.e.
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.Qq star mode ) .
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The
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.Nm
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driver automatically detects if the packet radio has fallen out of
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.Qq star mode ,
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and resets it back into
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.Qq star mode ,
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if the baud rate was set correctly by
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.Xr slattach 8 .
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.\" .Sh DIAGNOSTICS
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.Pp
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.Sh SEE ALSO
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.Xr inet 4 ,
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.Xr arp 4 ,
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.Xr sl 4 ,
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.Xr config 8 ,
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.Xr ifconfig 8 ,
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.Xr slattach 8 ,
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.Xr route 8 .
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.Sh BUGS
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Currently,
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.Nm
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is IP-only.
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Encapsulations for
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.Tn AppleTalk
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and
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.Tn ARP
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have been defined, but are not yet implemented in this driver.
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.Pp
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.Nm
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has not been widely tested on a variety of lower-level serial drivers.
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.Pp
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The detection and resetting of packet radios that crash out of
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.Qq star mode
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does not always work in this version of the driver.
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One workaround is to kill the
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.Xr slattach 8
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process,
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.Xr ifconfig 8
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the
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.Nm
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interface down, and then start a new slattach and rerun ifconfig
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to enable the interface again.
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.Sh HISTORY
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.Nm
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was originally developed for the
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.Tn Linux
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kernel by Stuart Cheshire of Stanford's Operating Systems and
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Networking group, as part of Mary Baker's MosquitoNet
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.Sy http://mosquitonet.stanford.edu/mosquitonet.html
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project.
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.Pp
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This
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.Nm
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driver was ported to
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.Nx
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by Jonathan Stone at Stanford's Distributed Systems Group and first
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distributed with
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.Nx 1.2 .
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