SV: RE: [HECnet] Hecnet and DDCMP

[Kevin Reynolds]

Johnny,

First and foremost, I want to learn how to configure and understand how these devices connected historically so I can troubleshoot the connectivity.   This gives me the best feeling of true understanding.   Unfortunately, I don't have a slew of these systems (I have a single Microvax II) that I can use to interconnect, so I am locked into simulating at least one end of the connection.   I was hoping to do this with simh.   Secondly, I was hoping to create error conditions and determine whether I can diagnose the problem.

As this is legacy hardware, protocols, and otherwise, I understand that aside from understanding how some of our modern protocols and systems emerged from knowledge of the old systems.   I am I really hoping to start a little further back to solidify my understanding of modern technology without all of the additional layers of distraction included with modern systems.

Did the VAX/VMS platform have an option to include PPP or SLIP previous to decnet +?   I have a good knowledge of these protocols.   I used slip back in the day when I had to connect with a pr1mos system that wouldn't allow pass-through connection to the internet.   PPP, especially multilink using PPP I have implemented multiple times (even recently...silly, but I didn't choose).   My ultimate goal is to pass decnet phase IV (not plus) traffic over the connection.

Thanks,
Kevin


> Date: Mon, 2 Jan 2012 11:15:34 +0100
> From: bqt at softjar.se
> To: hecnet at Update.UU.SE
> Subject: Re: SV: RE: [HECnet] Hecnet and DDCMP
> 
> The biggest issue I don't understand here is why.
> If you tunnel a serial port, you tunnel a serial port. DDCMP is totally 
> invisible to you.
> 
> You will not learn, or need to understand anything about DDCMP for this. 
> A serial port sends bytes. You pass those bytes one. Everyone is happy.
> 
> What kind of protocol is implemented, using those bytes, are very 
> invisible and irrelevant to the tunnel, just as it is to a cable.
> 
> You might as well tunnel SLIP, or PPP. It will work just the same.
> They are all just implementing a network layer on top of a serial 
> connection.
> 
> What are you really trying to accomplish?
> 
> Johnny
> 
> On 2012-01-01 01.57, The Presence wrote:
> > Bob,
> >
> > I really am wanting to use DDCMP for learning purposes. I want to build
> > a decnet phase IV network with DDCMP, however, I want to also have the
> > ability to pass traffic through to connect to additional nodes that are
> > net connected.
> >
> > Kevin
> >
> > ------------------------------------------------------------------------
> > To: hecnet at Update.UU.SE
> > Date: Sat, 31 Dec 2011 16:41:02 -0800
> > Subject: Re: SV: RE: [HECnet] Hecnet and DDCMP
> > From: bob at jfcl.com
> >
> >
> > What is it that you actually want to connect? For the most part, a
> > Multinet link simulates the "user experience" of a DDCMP connection
> > tunneled over IP. Multinet is a point-to-point DECnet circuit which,
> > except for the device names, is functionally identical to any DDCMP link.
> > The only reason I can see for using a real DDCMP serial connection
> > (either sync or async) would be to connect a machine that didn't support
> > an Ethernet interface.
> > Bob
> >
>