[Info-vax] Loosing all LAT connections on one machine in DECNet Network

[H Vlems]

On 14 apr, 23:05, JF Mezei <jfmezei.spam... at vaxination.ca> wrote:
> JCamCMKRNL wrote:
>
> LAT is sensitive to network problems.
>
> Say your VMS node is NODE-A.
>
> I would check the connecion of the AUI cable from node-A to the H-4000,
> and the vampire teeth connection of the H4000 into the thick coax (wow,
> that brings back memories!).
>
> LAT is very sensitive to glitches on the network and packet loss.
>
> The fact that LAT services to other node continue to remain operational
> on your decserver would tend to indicate that the coax backbone is
> working fine, otherwise all LAT service advertisements would go.
>
> Or is the VAX connected via AUI to the DELNI and the decserver connected
> directly to the DELNI ?
>
> After you notice that NODE-A is no longer advertised on your decserver,
> I would login to node-A and use LATCP to create a new service (perhaps
> called CHOCOLATE) and then see if the decserver sees the advertisement
> for the new service.
>
> I would also look at decnet statistics, notably counter for errors and
> retransmissions. (what version of VMS do you have ? LANCP might give you
> that too).
>
> Another thing to try is, from NODE-A:
> SET HOST/LAT NODE-A
>
> If this doesn't work, it means that even NODE-A has stopped advertising
> its own service and this might lead you to a cause (someone going int
> LATCP and removing the service ?)
>
> If the decserver removes the NODE-A service (not letting people
> reconnect) it means that LAT has not received keep alive messages for a
> certain period of time (not sure) and it won't publish service to NODE-A
> until NODE-A advertises the service again.
>
> DECNET is less sensitive to network problems.
>
> Also, another thing to try when the serice is down:
>
> From NODE-A
> $SET HOST/LAT PDP-11
>
> Does that work ?
>
> During outages, what (from NODE-A) does:
>
> MC LATCP SHOW SERVICES
> reveal ? Does NODE-A see its own service ? Does it see service provided
> by other nodes ?

The OP reports that four PDP-11's and one VAX are connected to a
DELNI. There's no transceiver in the path.
Which reminds me: what happens if you put an AUI loopback plug in the
global port of the DELNI< does the LAT service return immediately?

I'm not sure the OP has LAT running on the PDP-11's, even if they run
RSX-11M(+) the DECserver 200's may be used for reverse LAT.
Furthermore, outbound LAT is not enabled bu default, it must be
switched on  (mc latcp set conn/both iirc).

Hans

Hans