[HECnet] Use of Area 63 for Testing

[Paul Koning]

> On Apr 6, 2021, at 4:23 PM, Mark J. Blair <nf6x at nf6x.net> wrote:
> 
> MIM::DECNET.TXT states that area 63 is "Reserved for hidden area testing". Is area 63 routing suppressed by PyDECnet and/or any other methods of connecting to HECnet? If one were to play around with local nodes in area 63 without remembering to bring down the upstream HECnet connection, what would happen?

There's nothing special about area number 63 in the architecture, or in PyDECnet -- nor, as far as I know, in any other DECnet implementation.

The "hidden area" idea was used within DEC, since the Engineering Net at some point outgrew the 16 bit address space.  I don't really remember anymore how it was used.  I can try to construct some schemes that would work; the one I just constructed in my head is rather messy and I don't know if it is correct.  A possible answer relies on using max areas = 62 in most of the network, but = 63 in the routers that connect to hidden area entry points.

The other complication is that we'd have to resurrect the PMR / PASSTHRU object.  There's a PDP-10 version that's been posted, but my Macro-10 is much too feeble these days to read it.  I don't have the RSTS version, but I may have code that talks to it which may be sufficient.  Given a decent spec of how it works, a Python version would be easy.

	paul