Wolfgang Rupprecht <wolfgang@wsrcc.com> writes:

>> That's what STRIP seems to be. I'm not sure how complete the support is,
>> although it sounds awfully neat. (I nearly shorted out my keyboard with
>> my drooling, while I was reading about the system.)

>This does sound interesting.
>
>Does the STRIP code limit one to direct modem-to-modem links or will
>the Metricom pole-top relays relay packets for you in this mode?
>
>The Metricom web pages alluded to a peer to peer mode but didn't go
>into any details.

Yes, in peer-to-peer mode, the radios can talk directly to Metricom
radios or via poletops, or even (AFAIK, and as long as you have the
service) via Metricom's internal backbone that links poletops.

Perhaps Wolfgang missed the earlier reference to strip(4). Here's a
quote from the NetBSD manual page:


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.