Conference 7.286::fddi

1980.0. "Powering off 2100 disrupts FDDI ring DEFEA-DA" by CX3PST::NOTAMI::A_ANDERSON (CX03 2/H13 NSU/VAX MacGhille Aindrais) Wed Mar 13 1996 15:32

Hello all,

I have a customer with the following problem.  He has two 2100's each with a 
DEFEA-DA FDDI controllers at firmware rev 2.46.  One 2100 is running VMS 6.2 
the other DEC unix 3.2C.  Both are DAS attached to a FDDI ring.  If he powers 
off either system the FDDI rings goes down until the 2100 is powered back on 
and finishes its self test.  

He has 5 3-com Netbuilder hubs a Amdahl system and a Sequent system on the 
FDDI ring with the two 2100's all are DAS attached.  Using netstat on the
Sequent does not show the ring in a wrap state when either of the 2100's are
powered off.  

Also looking at LANCP and SDA on the VMS 2100 we do not see a downstreeam
neighbor (it should be the Unix 2100), the upstream neighbor shows up as the
Sequent.  But when he powers off the VMS 2100 the LEDs on the unix 2100 
blinks as expected.  The same goes with the VMS 2100's leds, they blink when 
the Unix 2100 is powered off.  

He has tried a new controller on the VMS 2100 and it made no differance.  

He also pulled the two 2100's off of the FDDI ring and made a test DAS ring 
with theses two and a third 2100 and could not reproduce the problem.  But 
without the 2100's the other 7 devices on the FDDI ring do not have a 
problems. 

  
Any ideas welcome

Alan Anderson  
Network Support CSC CS