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Conference netcad::hub_mgnt

Title:DEChub/HUBwatch/PROBEwatch CONFERENCE
Notice:Firmware -2, Doc -3, Power -4, HW kits -5, firm load -6&7
Moderator:NETCAD::COLELLADT
Created:Wed Nov 13 1991
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:4455
Total number of notes:16761

3276.0. "Flex channel and Concentrator port characteristics" by STOSS1::GRISSOM () Wed Feb 14 1996 10:35

    This is a two part question:
    
    1. It is recommended that when configuring FDDI lans that you use the
       split channel first. How do you implement this? Is it by default
       that if there are no FDDI lans currently configure on the hub. That
       when you configure the first lan, hub management uses a split 
       flex channel.
    
    2. Are there any known bugs in the firmware that will cause a
       concentrator port to switch configured characteristics. I configured
       a DC900MX with the "A" port as the entry port in to the ring (dual
       ring within the hub). Two days later the customer network goes down
       and it was determined that the concentrator port characteristics had
       changed to "M".
    
      HUB firmware..HW=F,SW=V4.0.4
      Concentrator900MX firmware...HW=v2,RO=v1.4,SW=V3.0.1
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3276.1NETCAD::MILLBRANDTanswer mamWed Feb 14 1996 13:1625
Hi -

Let me give a quick answer to your questions.  (Someone who works
more closely with this code may elaborate later.)

Reply to question 1:  You the user don't need to know about, and
especially not worry about, split channels.  Channel allocation
is done within the hub, based on what you told HUBwatch about
what ports of what modules you want connected.  The allocation
algorithm will select the split channels for FDDI if it can -
remember that split channels can be used only for connections
between modules in slots 1 thru 4 or 5 thru 8 (that's where
the term split comes in).  Say you wanted FDDI between a module
in slot 2 and slot 4.  Sure, you'd get a split channel if it
were available.  Then you want to add a module in slot 7 to 
your ring.  Voila, the connection is moved to another channel,
and you the user never need know the difference.

Reply to question 2:  There is a circumstance where info you
have configured takes effect but is not saved.  It can take
several seconds for config info to be saved into non-volatile
memory.  If you reset the module within 30 seconds of configuring
it, it may have been lost.

	Dotsie
3276.2NETCAD::DOODYMichael DoodyWed Feb 14 1996 13:286
    "A port out the front" is the default. The only way to have 
    the top-most port in a concentrator become an M port
    is to make the A port point out the back. This can 
    only be done by using Hubwatch (on purpose).
    
    -Mike
3276.3only in rare cases need users take actionNETCAD::MOWERWed Feb 14 1996 22:0935
    
    RE: .0
    
> 1. It is recommended that when configuring FDDI lans that you use the
>    split channel first. How do you implement this? Is it by default
>    that if there are no FDDI lans currently configure on the hub. That
>    when you configure the first lan, hub management uses a split 
>    flex channel.
    
    
    As Dotsie said in .1, channel allocation is not up to the user, and
    in general should not be a concern.
    
    
    There are a few [large/max] configurations that require all the hub 
    backplane resources, ("flex channels"), and may require some attention
    from the user.
    
    Specifically, in such rare cases, the user may have to move modules so 
    that the FDDI modules are divided "[roughly] evenly" between the two 
    "halves" of the hub;  (right half: slots 1-4, left half: slots 5-8).  
    
    By "roughly evenly" I mean that each half of the hub should have at least 
    2 FDDI modules that are are connected to the same FDDI backplane LAN.  
    (2 FDDI modules in the same half of the hub that are connected to the 
    same FDDI backplane LAN will typically be assigned by the MAM to use the 
    2 split channels on that half of the hub to communicate with each other).
    
    The root issue in these rare cases has to do with the fact that 2 of
    the backplane "flex" channels in the hub run only from 1-4 and 5-8;  
    (called the "split [flex] channels").
    
    Mike Doody explains the details of just such a case in 1540.9.
                                                                     Carl.
    
3276.4Splitting hairsPTOJJD::DANZAKThu Feb 15 1996 22:484
    Ah, so the answer is that we're splitting hairs about split channels...
    
    (groan)
    j