Blocking "Carrier Check Failure" messages from DECnet-Plus

[Jeremy Begg]

I am setting up an AlphaServer DS20E with VMS 8.3 and DECnet-Plus. The machine has two ethernet ports: a DE600 and a DE500 (the latter is embedded in a KZPCM-DA). At present it is not connected to any network.

When I boot the system, DECnet-Plus issues "Carrier Check Failure" messages every few seconds, e.g.

%%%%%%%%%%% OPCOM 6-NOV-2007 18:22:32.98 %%%%%%%%%%%
Message from user SYSTEM on SLIDER
Event: Carrier Check Failure from: Node LOCAL:.SLIDER CSMA-CD Station CSMACD-1,
at: 2007-11-06-18:22:32.984+10:30Iinf
eventUid 3DD7C520-8C95-11DC-A166-00062B00A698
entityUid 3D7DAA42-8C93-11DC-8535-AA0004000104
streamUid 4049C4E0-8C93-11DC-8624-AA0004000104

Of course, if I plug the network lead in to the KZPCM-DA the message will go away, but that's not an option at present.

I know there's an NCL command to block this but I haven't been able to work out the syntax. I think it's something like:

ncl> block event dispatcher outbound stream local_stream global filter ((csma-cd, csma-cd station csmacd-1), Carrier Check Failure)

but every variation I've tried produces the error "missing right bracket" or "missing left bracket".

Can someone help me out please?

Thanks,
Jeremy Begg

[Colin Butcher · Accepted solution]

Hi Jeremy,

Dredging up some old DCL I found this (below) which should help. It's just the command syntax I've extracted from DCL that generates an NCL script file. I can't remember why some of the stuff is in there, but it was an attempt to block some of the more common irritations from NCL. Another way to solve your problem is a cross-over cable, or to use a pair of loopbacks, both with the speed & duplex set at the console level.

"create event dispatcher sink local_sink"
"block event dispatcher sink local_sink specific filter = ((node ''c12d03_node_osifullname' event dispatcher sink local_sink), change filter)"
"enable event dispatcher sink local_sink"
"set event dispatcher sink * displayuids = false"


"create event dispatcher outbound stream local_stream"
"block event dispatcher outbound stream local_stream specific filter = ((node ''node_osifullname' event dispatcher outbound stream local_stream), change filter)"
"enable event dispatcher outbound stream local_stream"


"block event dispatcher outbound stream * global filter = ((csma-cd, station), carrier check failure)"
"block event dispatcher outbound stream * global filter = ((csma-cd, station), excessive collision)"
"block event dispatcher outbound stream * global filter = ((csma-cd, station), unavailable station buffer)"
"block event dispatcher outbound stream * global filter = ((csma-cd, station), unavailable user buffer)"
"block event dispatcher outbound stream * global filter = ((csma-cd, station), unrecognized individual destination pdu)"
"block event dispatcher outbound stream * global filter = ((csma-cd, station), unrecognized multicast destination pdu)"
"block event dispatcher outbound stream * global filter = ((routing), address unreachable pdu discard)"


"block event dispatcher outbound stream * global filter = ((dtss), synchronization completed)"

Cheers, Colin (http://www.xdelta.co.uk).

[Hoff]

Or just stick the tap into a spare switch or hub? Most of us have a spare around, after all, and now you don't have to remember to turn this stuff back on when/if you get to that stage. Poof. DECnet-Plus shuts up about the carrier. (It might still decide to squall about something else, though.)

Alternatively, toss the following NCL at the device:

DISABLE NODE 0 CSMA-CD STATION CSMACD-1

or whatever the device ENABLE command specified in NET$CSMACD_STARTUP.NCL might be; DISABLE what NET$CSMACD_STARTUP.NCL ENABLEs. To make this change survive a reboot, comment out the CREATE and ENABLE lines for the device in the file. This file is located in SYS$MANAGER: for the host.

Stephen Hoffman
HoffmanLabs LLC

[Martin Hughes]

You can also simply disable that interface

NCL> disable csma-cd station csmacd-1

[Jeremy Begg]

Colin, your suggestion sorted me out. This did the trick:

block event dispatcher outbound stream * global filter = ((csma-cd, station), carrier check failure)

The "=" would appear to be optional, BTW.

Thanks to all for the suggestion to simply disable CSMACD-1. This was my previous solution but not the one I was looking for.

[JohnDite]

You should be aware of your local NCL customization file

sys$startup:NET$EVENT_LOCAL.TEMPLATE which you have to rename to NET$EVENT_LOCAL.NCL
This file gets called during NET$STARTUP

Based on the event that you quoted, one of the first things to set in that file is

set event dispatcher sink * DisplayUIDs FALSE

That way you will save three (superfluous) lines for every DECnet event you get.

Cheers
John

[Jeremy Begg]

Hi John,

Yes I know about NET$EVENT_LOCAL but I did not know you could suppress the UIDs. I might just do that. Thanks!

Jeremy

[DECxchange]

Hello,
You might want to make sure your application is not trying to communicate down that ethernet port that is indicating the carrier check failure. You are probably getting this message because your Alpha is trying to do something with that port. Otherwise, did you consider putting a loopback plug on that port? Thanks.

[Willem Grooters]

Same proble in a similar config: I have the command that Hoff states, in my startup sequence after TCPIP has started. Problem "solved" :) it's only on startup that these messages occur and since boot is no daily activity, I can live with that.

[Hoff]

Willem, if you swap the ENABLE(s) for DISABLE(s) in the NET$CSMACD_STARTUP.NCL file, the burbles of messages issued for the (dis)connection(s) during the startup should vaporize.

The DISABLE I posted is the NCL command form that you'll use after DECnet-Plus has started.

By tweaking the NCL commands underneath DECnet-Plus, you can avoid even starting the (dis)connection. (In this area, DECnet-Plus is configured and managed more like a Unix tool; where you manually edit a configuration text file. And yes, editing this NCL startup file is documented.)

And the NCL commands and link state here don't affect the TCP/IP operations in any way, nor the use of the same NICs. The commands can be issued before or after the TCP/IP startup. Or you can disable the line in the NET$CSMACD_STARTUP.NCL startup script, and to thus prevent the NIC from starting.