[comp.unix.xenix] MNP levels

ingea@IFI.UIO.NO (Inge Arnesen) (07/25/90)

In article <62@comix.UUCP> you write:
>In article <59@marilyn.UUCP> shawn@marilyn.UUCP (Shawn P. Stanley) writes:
>>In article <3477@crash.cts.com> jca@pnet01.cts.com (John C. Archambeau) writes:
>>>Are there any MNP (level 5) MNP emulation packages for Unix/Xenix? 
>>
>>I'd be interested too, if there are sources involved!
>
>As far as I know MNP is a proprietary >hardware< protocol that
>is owned by Microcomm which is the M in MNP. . .; Microcomm
>licenses this technology to other OEM's however.

Yes and no. MNP level 1-2 is now in the public domain and MicroComm
has release emulation source for IBM PC. A few hackers have made
MNP lookalikes (which usually are even less compatible than the many
lisenced ones :-). Still, the original MNP levels 3-10 are still
property of MicroComm....

BTW: MNP is not a hardware protocol. Even if it usually runs inside a
modem, it is still an implementation of an algorithm.... and MNP is
as far as I know a SW implementation (written in C ?). If some
modem companies will put it in micro code you might be right in
calling it a hardware implementation, but not a hardware protocol
as such. I don't believe there is any hard wired MNP implementations
around (correct me if I'm wrong).

I have thought about making a MNP driver for XENIX, but after getting
MNP on my modem and finding out how useless it is (level 3), I
abandoned the idea. Even level 5 is not very interresting for news
transfers, since the news files are sent compressed and UUCP is a
pretty good protocol .....

I've found that on good lines, MNP levels or V.42bis only makes the transfers
of compressed files slower.



Inge (BoB)  { ingea@ifi.uio.no }
=========================================================================
==   Inge Arnesen, University of Oslo, Norway.                         ==
==                                                                     ==

mark@cristal.umpx.oz.au (Mark Fawcett) (07/31/90)

For all the folks who are interested in running MNP in software on
your Xenix machine, here is some more detailed information.

Microcom have released levels 1 to 4 into public domain, and this was
required prior to the CCITT approving it under the V42 standard for
error correcting protocols in modems.

MNP Level 5 compression is proprietry to Microcom but V42bis compression
is covered by CCITT standard V42bis.

It is not a difficult job to implement MNP is software on a Xenix machine
in C. Microcom have released source code for a rudimentary version which
is written in Microsoft C for ms-dos.

I would suggest that MNP is usefull for running interactive terminal 
sessions, but gets in the way of most protocols such as uucp etc which
will move news for you much faster. Mnp with V42bis compression is
particularly usefull for interactive terminal sessions whilst running
vi to edit C programs as the compression achieved with a decent 
implementation will typically be at least 100%.

If you would like any more detailed information send requests directly
to me and i will summarise to the net, if any level of interest is
shown.

.signature

-- 
Mark Fawcett - Microplex Pty Ltd	(mark@cristal.oz)

PHONE:	+61-2-888-3685		UUCP:		uunet!cristal.oz!mark
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