On May 8, 2013, at 4:51 PM, Dennis Boone wrote:
I gather the "multinet" protocol is how much of hecnet is tied
together. Is that right? Is there a protocol description for it, or
code that implements it?
It wraps decnet frames in udp frames, typically on port 700. The linux
decnet package has an implementation of it, and the source is reasonably
easy to follow.
I think I figured it out. The DECnet/Linux code is in dnprogs, file multinet.c
It's quite a hack. DECnet/Linux apparently only supports Ethernet datalinks. Or at least the multinet stuff hooks into the Ethernet machinery (via a tun/tap port). But it converts the packet stream into the point to point flavor of the protocol, at least a close enough approximation that it basically works.
Ok, that helps, because it basically means I need to do another point to point link (closely analogous to the simh DDCMP emulation).
One detail is unclear: it looks like the first four bytes of the datagram are a 2 byte sequence number followed by 2 bytes of padding. The code isn't doing anything with the sequence number on receipt. And it doesn't ever seem to reset the sequence number. So what, if anything, is it used for?
Part of the puzzle is that the DECnet routing spec requires point to point links not to lose packets -- which DDCMP guarantees. UDP does not, obviously. It doesn't even guarantee sequential delivery. And while DECnet can deal reasonably well with lost packets, reordered packets on a datalink are not something the state machine was designed for. I suppose that real world packet loss/reordering rates are low enough that it works well enough by the standards of the people who invented this scheme, even though it wouldn't have passed muster in the DECnet architecture team...
paul
Point to point or Ethernet-like?
I can't speak for the implementation, but from DECnet's point of view a
Multinet link is a point to point connection. A Multinet link connects
exactly one VMS host to exactly one other VMS host - it's not a multi host
bus connection like Ethernet.
Of course DECnet can route traffic thru a Multinet link just like it'd
route thru any other point to point connection, so DECnet machines on one
LAN can see DECnet machines on the remote LAN as long as the two Multinet
connected hosts are DECnet routers.
Bob
On May 8, 2013, at 4:43 PM, Bob Armstrong wrote:
I vaguely remember reading that there's simh support for it, but I don't
see it.
I don't think there's any specific simh support for a Multinet port, but
you can of course run Multinet "thru" simh (i.e. install Multinet on a simh
VAX/VMS system and tunnel DECnet thru the simh emulated Ethernet
controller).
I assume you're asking about a simh invention that talks to a remote
Multinet VAX/VMS system on the simh host side and pretends to be some other
device (like a DMR/DUP/DMV/whatever) on the simulated side - I've never seen
anything like that.
DECnet/Linux can supposedly emulate a Multinet tunnel. Is that what
you're thinking of? But in that case you're running DECnet on the Linux
host and simh has nothing to do with it.
I want to learn how to make my DECnet speak Multinet. Rob mentioned wanting to do the same for his "user mode router". So it would be another DECnet datalink. Point to point or Ethernet-like?
Yes, I saw the DECnet/Linux code. It's rather puzzling because it seems to tie into a tun/tap device -- so it expects Ethernet behavior. But then it converts to short headers, which suggests point to point behavior. Which is it? The data headers are only a tiny part of the difference between the two datalink flavors...
paul
I gather the "multinet" protocol is how much of hecnet is tied
together. Is that right? Is there a protocol description for it, or
code that implements it?
It wraps decnet frames in udp frames, typically on port 700. The linux
decnet package has an implementation of it, and the source is reasonably
easy to follow.
De
I vaguely remember reading that there's simh support for it, but I don't
see it.
I don't think there's any specific simh support for a Multinet port, but
you can of course run Multinet "thru" simh (i.e. install Multinet on a simh
VAX/VMS system and tunnel DECnet thru the simh emulated Ethernet
controller).
I assume you're asking about a simh invention that talks to a remote
Multinet VAX/VMS system on the simh host side and pretends to be some other
device (like a DMR/DUP/DMV/whatever) on the simulated side - I've never seen
anything like that.
DECnet/Linux can supposedly emulate a Multinet tunnel. Is that what
you're thinking of? But in that case you're running DECnet on the Linux
host and simh has nothing to do with it.
Bob
Gentlepeople,
I gather the "multinet" protocol is how much of hecnet is tied together. Is that right? Is there a protocol description for it, or code that implements it?
I vaguely remember reading that there's simh support for it, but I don't see it.
paul
On Wed, 8 May 2013, Johnny Billquist wrote:
On 2013-05-08 03:36, Connor Youngquist wrote:
Hello,
I would like to request area 32 for my usage. I've been watching HECnet
for a while now, and I'm ready to jump in and start learning. Cory has
mentioned that he will assist me in setting up the proper connections.
So noted.
Once he gets the port for multinet forwarded, I should have him linking through me (semi-temporarily).
Johnny
--
Cory Smelosky
http://gewt.net/ Personal stuff
http://gimme-sympathy.org Experiments
Hi, Gerry.
On 2013-05-08 01:58, G. wrote:
On Sat, 04 May 2013 17:56:51 +0200, you wrote:
To make a short follow up on this. I have not heard anything from our
Italian friends, and I think one big reason why this have never happened
is that there never seem to have been a big interest in it.
Sorry guys for my long silence on this topic.
No worry. It's not like it would signify the end of the world.
As far as I know, I'm the only one of the Italian DECnet reading and writing
here, and I'm just a spokesman (sort of). Lately, the whole Italian DECnet is
really just a couple of nodes and is seldom used. This is due to some people
moving from one location to another (even another country) and other people
loosing interest about it or having to devote their spare time to other tasks.
In the past year, for about six months someone of us had some Cisco gear as a
DECnet router, but it's since long gone and not expected to come back.
I don't think I've seen anyone else either, but they would be very welcome if they wanted to.
As for having other things to do, I can certainly understand that one...
Moreover (don't forget the spokesman thing), someone else once said he prefers
not joining our network to another because ours is an experimental one and he
wants to feel free to fiddle with nodes and addresses, and even switch online
unknown nodes, without fear of address clashes and such. Again, another one
with limited bandwidth said that all those "hello" packets coming in every 15
seconds from as many nodes as HECnet has would be too much for him (as a
matter of fact, we have raised networkwide our "hello timer" to 90 seconds).
This really should not need to be a big problem, anymore.
The broadcast traffic was certainly an issue with the bridge (which I recall having heard before, now that you mention it), but using either a VMS machine tunneling, or a Cisco box, this becomes a non-issue.
The same goes for nodes as well. If you are all in one area, it really isn't any different than today, unless you also occasionally setup other areas. Nodes within one area is totally at the discretion of the person(s) responsible for that area, and noone else.
And having one machine act as the router to the rest of HECnet means that traffic inside the area would be no different than today. And I would hope that atleast one person would have a suitable network connection, and a machine, to act as an area router...
The conclusion is that there is no common view about joining our DECnet (or
what remains of it) to HECnet, and every time I've submitted the question to
the other members there was always someone withdrawing or pushing against it.
That part I can't offer much help on. :-)
And I can understand that it's nice to be fully in control, and with less potential for conflicts and commitments. So I don't really feel like pushing hard either, but it would be nice if you could join.
A basic difference between other people joining HECnet and us, is that (as far
as I can understand) usually others are mostly individuals who then have not
to cope with different requirements and opinions, instead we are a group made
up of very different people, scattered all over Italy, from North to South.
We'll... We're scattered around the whole world. Don't make it easier...
However, I think that it works fairly well, for some reason. Maybe because we are not trying to make much of it, but enjoy the small things working.
All in all, I just became uncle and I have something else to think about! :)
For what is worth, I'm personally very grateful to all who think about us and
I'll continue to read and write here every time I can!
Hey! Congratulations. And whenever you feel like it, you can just request an area, and hook up with the rest of us. It would be fun. ;-)
Johnny
On 2013-05-08 03:36, Connor Youngquist wrote:
Hello,
I would like to request area 32 for my usage. I've been watching HECnet
for a while now, and I'm ready to jump in and start learning. Cory has
mentioned that he will assist me in setting up the proper connections.
So noted.
Johnny
-----Original Message-----
From: owner-hecnet at Update.UU.SE [mailto:owner-
hecnet at Update.UU.SE] On Behalf Of G.
Sent: 08 May 2013 00:58
To: hecnet at Update.UU.SE
Subject: Re: [HECnet] Italian DECnet...
On Sat, 04 May 2013 17:56:51 +0200, you wrote:
To make a short follow up on this. I have not heard anything from our
Italian friends, and I think one big reason why this have never
happened is that there never seem to have been a big interest in it.
Sorry guys for my long silence on this topic.
As far as I know, I'm the only one of the Italian DECnet reading and
writing
here, and I'm just a spokesman (sort of). Lately, the whole Italian DECnet
is
really just a couple of nodes and is seldom used. This is due to some
people
moving from one location to another (even another country) and other
people loosing interest about it or having to devote their spare time to
other
tasks.
In the past year, for about six months someone of us had some Cisco gear
as
a DECnet router, but it's since long gone and not expected to come back.
Moreover (don't forget the spokesman thing), someone else once said he
prefers not joining our network to another because ours is an experimental
one and he wants to feel free to fiddle with nodes and addresses, and even
switch online unknown nodes, without fear of address clashes and such.
Again, another one with limited bandwidth said that all those "hello"
packets
coming in every 15 seconds from as many nodes as HECnet has would be too
much for him (as a matter of fact, we have raised networkwide our "hello
timer" to 90 seconds).
I have a solution for this one with the user mode DECnet router I wrote. :-)
If Italy used it and someone on HECnet you peered with used it, then all the
hellos from the rest of HECnet could disappear. If there was not too much
traffic between Italy and the rest of HECnet I would be happy to be the
peer, just remember it is my domestic broadband that would be being used.
Regards
Rob
The conclusion is that there is no common view about joining our DECnet
(or
what remains of it) to HECnet, and every time I've submitted the question
to
the other members there was always someone withdrawing or pushing
against it.
A basic difference between other people joining HECnet and us, is that (as
far as I can understand) usually others are mostly individuals who then
have
not to cope with different requirements and opinions, instead we are a
group made up of very different people, scattered all over Italy, from
North
to South.
All in all, I just became uncle and I have something else to think about!
:) For
what is worth, I'm personally very grateful to all who think about us and
I'll
continue to read and write here every time I can!
Bye, :)
G. (Bologna - Italy)
