Re: DECnet IV over Multinet Circuit

In article <dnq3ab0c2k@xxxxxxxxxxxxxxxxxx>,
healyzh@xxxxxxxxxxx writes:
> I'm trying to figure out how to resolve a problem with connecting two
> Hobbyist systems using DECnet Phase IV over Multinet. We have it working,
> but it won't work reliably. After a very short time the circuit will go
> down, and won't come back up without some work.
>
> I can get it back up if I do the following on the VAX:
> MCR NCP SET CIRCUIT TCP-0-0 STATE OFF
>
> Then wait a few minutes and then issue a:
> MCR NCP SET CIRCUIT TCP-0-0 STATE ON
>
> The circuit will stay up for a few minutes. I was able to log into the
> remote system and log out, but a couple minutes later the circuit was
> back down.
>
> On another try of this, I logged in and fired up MONITOR SYSTEM, and have
> left it running. As a result the line has been active for about 16 hours
> now.
>
> So it appears that as long as there is activity on the circuit, it will stay
> up, but as soon as there isn't any activity for a short time, it will drop,
> and then requires the above trick to get it to come back up.
>
> I don't know if this is an issue with DECnet, Multinet, or the Firewalls
> that are between the two systems.
>
> Does anyone have any ideas on this?
>

Our networking people installed a (industry standard) firewall here some
time ago that has turned TCPIP in to a stateful protocol. That is, it
actually tracks sessions running through it and if a session is inactive
for a (operator defined) period of time it stops passing data for it should
it become active again. A real braindead idea, but I don;t have control
over it and it has forced me to institute keep-alives on all our remotely
accessable servers even knowing and agreeing with Karn and Jacobsen on
"Keep-alives, a bad idea". (We won't even go into the fact that this
results in exactly the supposed network problem they claim it was intended
to prevent!!)

bill

--
Bill Gunshannon | de-moc-ra-cy (di mok' ra see) n. Three wolves
bill@xxxxxxxxxxxxxxx | and a sheep voting on what's for dinner.
University of Scranton |
Scranton, Pennsylvania | #include <std.disclaimer.h>
.