Path: utzoo!attcan!uunet!lll-winken!lll-lcc!ames!pasteur!ucbvax!TWG.COM!ljm
From: ljm@TWG.COM (Leo J McLaughlin)
Newsgroups: comp.protocols.tcp-ip.ibmpc
Subject: IP over NetBIOS (Use of broadcast datagrams)
Message-ID: <8901041624.aa04429@Obelix.TWG.COM>
Date: 4 Jan 89 22:16:00 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 30



Some time ago I posted a specification for IP over NetBIOS.  The primary
concern of the responses I have recieved is the use of broadcast datagrams
instead of NetBIOS group names for IP broadcasts.

The problem with using NetBIOS group names for broadcast is that it isn't
quite as simple as just saying 'use IP.xx.xx.xx.xx'.  For instance, if I have
a class 'B' address that uses 24 bits of subnetting I need to post 7 listens:
IP.81.54.4.2, IP.FF.FF.FF.FF, IP.81.54.FF.FF, IP.81.54.4.FF, IP.00.00.00.00,
IP.81.54.00.00, and IP.81.54.4.00.  Worse, this pretty much prohibits NetBIOS
hosts from being multihomed (each logical interface using 7 listens), requiring
the host software to monitor the link layer interfaces chosen before allowing
IP address assignment.  (Latest IP broadcast info taken from the December 25th
edition of the Requirements for Internet Hosts specification).

My belief at the time was that more NetBIOS applications would mind the
stealing of all those NCBs than would mind the use of broadcast datagrams.
We tested our implementation with a handful of IBM programs (the most
important of which was PC LAN) and all of them worked.

So I ask for anyone who knows of some common NetBIOS applications which do
require the non-use of broadcast datagrams (or for that matter of any NetBIOS
implementations and/or applications which would mind if many listens were
posted) to please send me mail.


leo j mclaughlin iii
The Wollongong Group
ljm@twg.com