[Info-vax] What would you miss if DECnet got the chop? Was: "bad select 38" (OpenSSL on VMS)

[Michael Moroney]

Johnny Billquist <bqt at softjar.se> writes:

> From DECnet point of view, it is just a simple line. Called something 
>like TCP-0-0. And you work with it just like any other line in DECnet. 
>It's a point-to-point line, over which DECnet establish a circuit to the 
>remote machine. No different than if you were to just have a simple 
>RS-232 cable between two machines, using DDCMP, and then have DECnet 
>communicate over that.

>Really, this is identical.

Oh, that is interesting. So the Multinet DECnet over IP is just a
virtual point-to-point serial line, not a fake Ethernet like I was
thinking it might be.  Real point-to-point links were common in the
early days of DECnet before ethernet pretty much took over for
short distance links.

>Multinet then have a tool to define the TCP/IP connection between the 
>two points, which is totally outside the knowledge of DECnet.

So for a more complicated network, you'd need several of these virtual
point-to-point links so everyone could talk to everyone else.

I don't know offhand if DECnet V has support for point-to-point links
at all but if it does, Multinet's virtual p-p links should work with
it as well. But with OSI over IP, there is no need other than to talk
to a Phase IV node.

>And in the Multinet tool, you define the remote host and port. Multinet 
>will then establish that connection, using TCP or UDP. And once it is 
>up, then from the DECnet point of view, you have a link which transports 
>bytes between the two nodes, using that line.

That makes sense.  A TCP link from A to B with a driver for a virtual
serial line on each end that puts the stuff over the TCP link.
(Or UDP. I don't know the advantage of one over the other for something
like that)

>DECnet can route things just as normal. One more line does not change 
>anything fundamentally. It's just a line.



As to the argument over the Multinet Phase IV p-p connections and the
Phase V OSI over IP stuff, there is no reason why both can't coexist,
as long as they use different TCP/UDP ports. To IP it's just more
TCP/UDP packets.

As to VSI, for Phase IV it's just a matter of not breaking anything
in the Multinet code.  For Phase V it may depend on working on the
Multinet PWIP driver, or maybe it will just work.