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

[Dirk Munk]

Johnny Billquist wrote:
> On 2016-10-01 20:47, Dirk Munk wrote:
>> David Froble wrote:
>>> The way I understand it, DECnet IV doesn't know a thing about IP.  It is
>>> a feature in Multinet that does the routing over IP.  So when you
>>> mention DECnet over IP as if it is a DECnet feature, you've skirted
>>> reality.
>>
>> I think it is using a kind of IP tunnel, at least it is using IP port
>> 700. I will try to find out what it does exactly. Just routing is
>> impossible of course, DECnet Phase IV packets are very different from IP
>> packets, and can not be handled by an IP router.
>
> First of all, for someone who pretends (or claims) to know so much about
> TCP/IP, you should know that there is no ports in IP. That comment is
> just plain bad.

Yes, I know, the ports are with UDP or TCP etc.

> Second, you really should learn the topic before firing off all the
> silly comments you do.
>
> David is entirely correct. The Multinet DECnet-over-IP really means that
> DECnet is totally unaware of TCP/IP. Yes, the Multinet tunnels can use
> both UDP and TCP, and the default port in both cases are 700.
>
> 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.
>
> Multinet then have a tool to define the TCP/IP connection between the
> two points, which is totally outside the knowledge of DECnet.
>
> 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.
>
> DECnet can route things just as normal. One more line does not change
> anything fundamentally. It's just a line.
>
> The two nodes so connected could be on the same or different areas. All
> that is required is that DECnet can do routing, which have nothing to do
> with TCP/IP.
>
> And the TCP/IP layer just have a connection between the two machines,
> using the normal TCP/IP network. And what is transported on that
> connection is totally irrelevant, as far as TCP/IP is concerned. It's
> just bytes.
>
> Now, how hard can it be to understand?

Not very hard, and now I understand why people think Phase V is doing 
the same, which it isn't. It is *not* tunneling like with Multinet. The 
only thing that is needed with Phase V is that the system on the other 
side understands DECnet over IP. That is exactly the same as setting up 
a FTP connection, if the other side doesn't have FTP loaded, it will not 
work. Other then that, with Phase V you can set up a DECnet over IP 
connection to any system in the world without having to set up tunnels. 
You do not use DECnet Phase IV addresses, or NSAP addresses, just IP 
addresses. No DECnet routing, no CLNS routing, just IP routing.

> And in which way is this bad?

Have I ever written it is bad, or made that suggestion? That is just 
your idea.

> And if you have phase V nodes that talk to each other, using whatever
> transports and protocols they want, in which way does that matter here?

The subject was that Phase V and Multinet both offer DECnet Over IP, and 
they seem incompatible. The question is what VSI is going to support.

>
> And finally, yes, I've implemented this same functionality in RSX, and
> thus RSX and VMS nodes using DECnet phase IV can communicate with each
> other, using the Internet. In fact, I am using this today with HECnet,
> which is a Phase IV DECnet, which covers most of the world, actually.
> And we use these Multinet links all the time (it's not the only
> transport, but it is one, and it works).
>
>     Johnny
>