3 Jan
2015
3 Jan
'15
2:54 a.m.
On 01/02/2015 08:43 PM, Johnny Billquist wrote:
One can tunnel most anything over GRE, even raw Ethernet frames,
regardless of the higher-level protocols. Hence the 'G' for
"Generic".
Yes. But you need some ingress and egress that makes use of it. Or
else
we could just as well argue that UDP can tunnel anything.
...which it can. ;) On a Cisco, assigning a DECnet cost to an
interface (and a GRE endpoint is a pseudo-interface on a Cisco) forms
that ingress/egress.
(I know YOU know this; I'm saying it for the benefit of those
here who
are just learning about this)
Actually, I don't know the details, even though I pretty much know how
it *could* be done. I've pretty much never actually worked on a Cisco
box. :-)
However, DECnet costs cannot possibly be related, as we're now not
talking about DECnet protocols. (LAT and MOP are not using DECnet...)
You need to somehow tell the Cisco box to grab all ethernet packets with
a certain protocol number, and pass those on over the tunnel, and have
the other end do the reverse.
Assigning a DECnet cost to a tunnel endpoint pseudo-interface causes
it to pay attention to DECnet packets.
Which is not LAT and MOP. Which is what I've written multiple times now.
:-)
Right. I didn't say it was.
DECnet packets are routed by the Cisco router. MOP and LAT are not
protocols running on top of DECnet, but are their own protocols directly
on ethernet. Which is also why they in essence are "local only", as they
cannot be routed.
...but they can be bridged, which you can ALSO do with a GRE tunnel.
The very same GRE tunnel as is handling DECnet, in fact.
-Dave
--
Dave McGuire, AK4HZ/3
New Kensington, PA