28 Mar
2021
28 Mar
'21
8:30 p.m.
I have always wondered whether 'Multinet' might have been a figment of
some marketeer's imagination.? DEC's sales people had some remarkable
gaffs, particularly when transitioning from the 36 to 32 bit line.? But
I'm sure they were not unique in that regard.
Under Tops-20, 'Multinet' has a _very_ specific meaning; it is the
MNETDV module (the Multinet driver) is what handles routing IP packets
over different physical media, in this case, an AN20 (to an IMP), an NI
and CI.
I can't remember what equivalent for DECnet is called in 36 bit land,
but it can be routed over a CI, an NI or over a DTE to DN20 (MCB).?
There are some additional devices, but I don't know if they were
implemented; I think ROUTER.MAC handles some of that.
------------------------------------------------------------------------
On 3/28/2021 1:52 PM, Paul Koning wrote:
I didn't see that.
I have never used the product called Multinet myself. When I use the term
"Multinet" it has always referred to the encapsulation of DECnet point to point
routing packets with a 4 byte header, sent either as UDP packets or over a TCP stream.
This is what I understand to be the so-called "Multinet datalink" (which as I
have said many times isn't an actual datalink and reflects only the utter ignorance of
its creators). That "protocol" should be avoided; if there is no alternative
then only the TCP variant should be used. The UDP variant is utterly unfit for any use in
any application whatsoever and always has been; I should probably delete it from PyDECnet
rather than permit it with a warning as I currently do.
If the product called Multinet also supports DDCMP, that's a different matter
entirely. I have never heard of any such thing. How does it work? Is it compatible with
DDCMP over TCP as implemented in SIMH? If yes -- and even if it only supports only
connect or listen but not both concurrently as SIMH does -- it should work with PyDECnet.
I'd be interested in hearing about it. If it isn't compatible with the SIMH
version for some other reason, then I would expect it not to work with PyDECnet either.
If so, and if someone can supply me with a description of how it operates, hopefully with
at least some protocol captures, I may be able to add support for it.
paul
> ------------------------------------------------------------------------
> On Mar 28, 2021, at 12:59 PM, Robert Armstrong <bob at jfcl.com> wrote:
>
> Johnny already said it, but it's worth repeating that Multinet WILL do DDCMP
over TCP (yes, TCP not UDP) if you ask it to. It's unfortunately not the default, but
it's easy to change.
>
> Bob
>> ------------------------------------------------------------------------
>> Paul Koning <paulkoning at comcast.net > wrote:
>> No, you're confusing DDCMP and Multinet.
>> Multinet isn't a datalink protocol; it's merely a wrapper for
>> the routing layer packets.