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STRIP(4)                  NetBSD Programmer's Manual                  STRIP(4)


NAME

     strip - packet-mode network device driver for the Metricom Ricochet radio


SYNOPSIS

     pseudo-device strip [count]


DESCRIPTION

     Configures count strip interfaces, named strip0, strip1, etc, into a ker-
     nel built from a config file containing the given entry.

     Each strip interface is a pseudo-device driver for the Metricom Ricochet
     radio, operating in peer-to-peer packet mode.

     The strip driver takes outbound network packets, encapsulates them using
     the Metricom "starmode" framing, and sends the packets out an RS-232 in-
     terface to a Metricom Ricochet radio.   Packets arriving from the radio
     via the serial link are decapsulated and then passed up to the local
     host's networking stack.

     strip is an acronym for Starmode Radio IP.

     In many ways, the strip driver is very much like the sl(4) SLIP pseudo-
     device driver.  A strip device is attached to a tty line with
     slattach(8).  Once attached, the interface is configured via ifconfig(8).
      The major difference between the sl(4) SLIP pseudo-device driver and the
     strip driver is that SLIP works only between two hosts over a dedicated
     point-to-point connection. In contrast, strip sends packets to a frequen-
     cy-hopping radio, which can address packets to any peer Metricom radio.
     rather than just to a single host at the other end of a point-to-point
     line.  Thus, one strip pseudo-device is usually sufficient for any ker-
     nel.

     In other respects, a strip interface is rather like an Ethernet inter-
     face.  Packets are individually addressed, and subsequent packets can be
     sent independently to different MAC addresses.  However, the "Star-mode"
     framing and MAC addressing are not in any way compatible with Ethernet.
     Broadcast or multicast to more than one radio is not possible, due to the
     independent frequency-hopping operation of the radios.  The interface
     flags IFF_POINTOPOINT and IFF_BROADCAST are not supported on strip inter-
     face.

     In other words, strip implements a multiple-access, non-broadcast device,
     accessed via an RS-232 serial line, using a proprietary packet framing
     scheme.

     This version strip driver maps IP addresses to Metricom radio addresses
     using statically configured entries in the normal routing table. These
     entries map IP addresses of peer radios to the MAC-level addresses.  The
     exact syntax of this mapping and an example are discussed below.  The In-
     ternet Assigned Numbers Authority (IANA) has allocated an ARP type code
     for use with STRIP. A future version of this driver will support arp(4)
     to obtain the IP address of reachable peer radios dynamically.


ADDRESS CONFIGURATION

     This version of the STRIP driver requires static pre-configuration of the
     mapping from IP addresses to radio MAC addresses.  The route(8) command
     should be used to bind a peer STRIP host's radio IP address to the peer's
     link-level radio address.   Radio addresses are encoded using the hex
     equivalent of the radio's decimal ASCII address.  For example, the fol-
     lowing route command will configure a routing entry to a radio with a MAC
     address of 1234-5678, and an IP address 10.11.12.13, reachable via the
     strip0 interface:


          route add -host 10.11.12.13 -link strip0:1:2:3:4:5:6:7:8

     Generalising from this example to other IP addresses and to other 8-digit
     MAC addreses should be clear.


RADIO CONFIGURATION

     The Metricom radios can auto-baud at speeds up to 38.4k baud.  At higher
     speeds -- 57600 or 115200 -- the radio cannot autobaud.  When running at
     high speeds, the radio's serial port should be manually configured to
     permanently run at the desired speed.  Use a terminal emulator and the
     Hayes command ATS304=115200 to set the serial baudrate to the specified
     number (or 0 for autobaud).  The command AT&w will then save the current
     radio state in non-volatile memory.

     Metricom radios can operate in either ``modem-emulation'' mode or in
     packet mode (Starmode). The strip driver automatically detects if the ra-
     dio has fallen out of starmode, and resets it back into starmode, if the
     baud rate was set correctly by slattach(8).


SEE ALSO

     inet(4),  arp(4),  route(8).  sl(4),  slattach(8),


BUGS

     Currently is IP-only.  Encapsulations for AppleTalk and ARP have been de-
     fined, but are not yet implemented in this driver.

     strip has not been widely tested on a variety of lower-level tty drivers.

     The detection and resetting of radios that crash out of Starmode does not
     always work in this version of the driver.  One workaround is to kill the
     slattach process, ifconfig the strip interface down, and then start a new
     slattach and rerun ifconfig.


HISTORY

     strip was originally developed  for the Linux kernel by Stuart Cheshire
     of  Stanford's Operating Systems and Networking group, as part of Mary
     Baker's  MosquitoNet http://mosquitonet.stanford.edu/mosquitonet.html
     project.  This strip driver was ported to BSD by Jonathan Stone at Stan-
     ford's Distributed Systems Group and first distributed with NetBSD 1.2.

NetBSD                          March 10, 1996                               2