[HECnet] DECnet et al

[Johnny Billquist]

On 2011-07-17 20.41, hvlems at zonnet.nl wrote:
Johnny, in general I am a strong believer in the motto that if someting isn't broken then you shouldn't try to fix it.
And I always felt that a bridged ( or switched :-) lan is "better" than a routed lan, provided enough bandwidth is available.

Thanks. The problem is that there are limits that a bridged ethernet will hit, and we're getting close to where it will hurt in HECnet.
It simply does not scale well.

That is why it might be that we need to do something else eventually. Either split so we have several smaller segments, with normal DECnet machines routing in between them, or else write a virtual router. Who knows what we'll do in the end. :-)

	Johnny

Hans
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-----Original Message-----
From: Johnny Billquist<bqt at softjar.se>
Sender: owner-hecnet at Update.UU.SE
Date: Sun, 17 Jul 2011 20:34:53
To:<hecnet at Update.UU.SE>
Reply-To: hecnet at Update.UU.SESubject: Re: [HECnet] DECnet et al

On 2011-07-17 20.22, Peter Lothberg wrote:
But HECnet as a whole is not connected to this segment...

      I thought the majority of it was...     There are a few people, like me, who
are using Multinet but only a few cases.   I thought pretty much everything
was bridged.

      [FWIW, Multinet tunnels a point-to-point DECnet link, essentially like a
DDCMP link, over UDP.   For that you really need to have a router at either
end to pass traffic for other machines on either LAN.]

Bob


Johnny,

If you can make a DECnet router, (l3...) or make the Internet look like point-to-point
(ddcmp) links, it would work 'better'. As sending all areas as 'rip
vectors' every second is not'usefull'.

Yes. The bridge is simple, but not really ideal. It causes a lot of
traffic that would be better if we could restrict.

But for a router, we need to talk the DECnet routing packets, which I
think might not be that bad, but then also route DECnet packets, which
means much more cleverness. I'm afraid I definitely don't have time for
all that.
But it would be nice. You could even be extra clever and only present
one DECnet node with n interfaces, one for each endpoing that currently
have a bridge. So it would seem like everyone had a connection to that
router, but no direct connection to the other endpoints. So we'd have
routing traffic running p-t-p to the virtual router, but no need to
spread that traffic all over the earth, as is done today. Each end would
still be running the bridge just like today, but the central hub would
be rather different.

And I'm offline, as I only speak Multinet and Decnet in GRE... (and
takes for endpoints?)

Yeah. I know... I think you are not the only one not at all on the
bridge, but I can't remember anyone else off hand.

	Johnny