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From: jbvb@VAX.FTP.COM (James Van Bokkelen)
Newsgroups: comp.protocols.tcp-ip.ibmpc
Subject: Re: multiplexing interfaces (was 'ethernet over pcnet')
Message-ID: <8807020308.AA01043@vax.ftp.com>
Date: 2 Jul 88 03:08:57 GMT
References: <8807020133.AA00845@vax.ftp.com>
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I agree, that my message wasn't intended to answer Brendan's stated question,
which revolved around what he could do with his existing IBM PC LAN cards.
I didn't reply to the original message, since I had nothing specific to say
about it.

However, in the course of giving Brendan a pretty good solution for his
broadband cards, you touched on the subject of multiplexing interfaces,
and I felt that I did have something to say about them...  Your mention
implied that multiplexing interfaces were relatively new on the scene,
and rare, when in fact, commercial offerings of multiplexing interfaces
considerably pre-date and outnumber the IP-over-NETBIOS variety you described.
This was why I changed the subject line...

A correction: I mentioned the IBM Adapter Support Interface (TOKREUI) as
being one of the multiplexing hardware drivers, supported by TCP/IP from
both us and IBM, as well as most LAN programs (I haven't yet encountered
anyone who wrote their own driver for the IBM 802.5 adapter).  I view this
as an excellent example of what can be done with a properly designed and
documented multiplexing interface.  It has even been supported by some of
IBM's competitors in the 802.5 market (although the quality of the emulation
can be uneven, just like many non-IBM NETBIOSes).

We have placed a somewhat less elaborate interface in the public domain
(our Packet Driver spec), which has been used by about half of the FTP
OEMs and customers I mentioned.  A version of the CMU PC-IP which supports
this has been done by Karl Auerbach, and other p-d and commercial software
may appear in the future.  We obviously don't have the clout of 3Com or
Microsoft, but our spec has been in the field for more than a year, and wins
on a few technical considerations, as well (MAC/Vector binds only device
drivers, and doesn't have an un-bind function).

One further comment: Banyan Vines 3.0 servers function as IP routers, using
both the normal IP encapsulation for each attached LAN (if a standard
encapsulation exists), and an IP-over-Banyan encapsulation which allows
TCP/IP to be used on any of the less-standardized LANs that Vines has been
implemented on.  This is an effort in the direction of "full connectivity
for TCP/IP across the whole multi-segment LAN" that goes somewhat further
than using NETBIOS (with its one-cable addressing limitations) as a local
encapsulation.  Perhaps other LAN vendors will develop similar offerings.

James VanBokkelen
FTP Software Inc.