Conference netcad::hub_mgnt

>> Workaround: Install a UTP MAU on the global port of the  delni's and connect 
>>	    it to a UTP port on the DECbridge 900MX

    Try putting a loopback connector on the global port of the DELNI and
    flip the switch into global mode.  This will disable any heartbeat in
    the DELNI.  If this doesn't work then go with a DETPM on the DELNI
    Global port and use a crossover cable to connect into one of the UTP
    ports in the DS 900EF.

    Let us know if this cures the problem.
    
>> Are there special transceiver cable length restrictions for the 900MX????

    No
    
    dave

Thanks for the reply

I  installed a DETPM on the DELNI, put it in global mode and connected it via a
crossover cable to port 6 of the Bridge. This worked fine but it's still a
workaround.

Do we have to disable the heartbeat on a DELNI when it's connected to a 900MX,
and if yes why???


Regards Gerrit
    

    It's not believed that there is anything wrong with the 900MX.
    There is a verrry long history of network problems with using DELNI's 
    in local mode (where by default when it is in local mode, it
    puts out heartbeat, and if it is not disabled, it creates various
    forms of havoc on networks. I have a file miles long which is an
    extraction of a bunch of classic notes from another notes file on
    the hazards of DELNI's used in local mode to connect to the rest of
    an extended LAN. I believe the classic notes are extractions from one 
    of the itterations of the ETHERNET notes conference.
       BTW there is a newer DELNI now being sold by DEC which is a nice 
    upgrade to the older classic DELNI with its er... classic problems. 
    The newer DELNI *doesn't* exhibit the older DELNI's "classic" behavior.
    
    Bob

Thanks Bob for the reply

>       BTW there is a newer DELNI now being sold by DEC which is a nice 
>    upgrade to the older classic DELNI with its er... classic problems. 
    
Customer is using the new style DELNI.
 
>    The newer DELNI *doesn't* exhibit the older DELNI's "classic" behavior.

What do you mean by classic behavior, what I know from the new style DELNI
(learned from the Enet notesfile) that it operates electrical identical to
the classic DELNI, just some minor differences like full/half step signaling
en heartbeat timing

I installed the workaround as in .2 and can't go back to do some further testing
because customer will not let me do the testing (production reason)

My original question remains:  is this a legal configuartion???

             VAX Systems-----------------|DELNI (Local mode)
             FDDI ring-- DECbridge 900MX-|
                           

If "yes" we have 900MX/DELNI combination problem and I have to escalate because
all four Bridge-DELNI combinations show the same problem.

If "no" we have to improve the documentation on using the AUI port

Regards Gerrit



   


                               

    

    >              just some minor differences like full/half step signaling
    > en heartbeat timing               
    
    That's not a considered a minor difference in certain network
    configurations. That is the difference I was referring to when
    mentioning the classic problems with the old DEC Delni's. That
    is that they used full step signaling. Other than the full step
    on the older and half step on the new delni's, yes they are 
    electrically identical.
    Putting either a MAU or an AUI loopback on the delni global port
    when the delni is used in local mode is an accepted configuration
    when it is desired to disable heartbeat on a delni. This has been
    documented in many Digital network interconnect manuals and
    configuration guides.
    
    Bob

    But does a loopback with the DELNI in global mode solve the DS 900EF
    AUI to DELNI port and reduced thruput problem?
    
    dave