Conference netcad::hub_mgnt

>1. Are there some restrictions to assign the six Ethernets on the backplane, 
>or can I use any of the 15 IMB's including the half-ones? (IMB11a,11b and 
>12a,12b)

The current MAX modules (DECrepeater900TM, DECserver900TM) are only capable
of connecting to the thinwire and matrix segments 1 thru 6.  This is due to 
a hardware restriction (cost savings) in the line cards.  It is not due to 
any restriction in the backplane hardware, or in the Hub Manager's matrix
allocation code.

In theory, there can be an Ethernet line card which can connect to any of 
the backplane LAN segments.

>2. Are there some restrictions to assign the FDDI Point_to_Point connections 
>on the backplane or is it possible to use all the IMB's? 

Any of the backplane segments can be used for FDDI.  The upcoming FDDI
concentrator line card can connect to any of the backplane matrix segments.

FYI:  The matrix allocation algorithm allocates Ethernet segments from 
segment 1 on up, and FDDI segments from 14 down.  (If two FDDI cards to
be connected are close enough to one another to use the split channels,
these are used.)

Good luck on the tool.  Feel free to post a pointer to it so we can
try it out.
							-Shawn

    Thanks a lot
    
    "matrix segments 1 thru 6" means 1 IMB on the upper connector and 5 IMB's
    on the lower connector. Is that right?
    
    PS
    By the way, is there a technical manual avaiable for DEChub900 and its
    modules?
    That would help a lot (for a free configtool demo!) 

>    "matrix segments 1 thru 6" means 1 IMB on the upper connector and 5 IMB's
>    on the lower connector. Is that right?
 
Yep.  I should have phrased it as, the flexible channel on the upper connector
and the first 5 lower connector channels.
   
>    By the way, is there a technical manual avaiable for DEChub900 and its
>    modules?

The only documentation I've seen on the backplane matrix is the "System
Spec", by Rich Graham.  It's available from:

  quiver::PROJ$722:[ONEHUB.SYSTEM]ONEHUB_SYSTEM_SPEC_<latest version>.PS

This area requires access rights.  Contact Rich at levers::graham if you 
have trouble accessing it.

I don't know of any document which describes each product's backplane 
connection capabilities.
							-Shawn

    I would be interested in the work you are doing. I would like to
    understand its relationship to HUBwatch.
    
    Please send mail to LEVERS::SWEET with details of your plans.
    
    bruce

    
    This needs some correction.
    
    There are 120-some 'signals' on the 900 backplane, which modules group
    to form 'channels'.  Each type of module can have its own definition of
    what constitutes a 'channel' (as it happens, all current modules use
    the same groupings, but future modules will use others that overlap
    with the current ones).
    
    The current Ethernet full-height modules use the same channels; one
    signal set on the upper connector and 5 on the lower connector (the new
    half-height repeater will not be able to use the 5 on the lower
    connector).  This is the source of the restriction that there can be
    only 6 backplane ethernets.  There are enough signals to make the
    theoretical maximum 15 + the thinwire, but this was not done for cost
    reasons.
    
    Note that when you use HUBwatch (or any other SNMP manager that knows
    the correct MIBs) to configure the backplane connections you _cannot_
    select which channels are assigned.  All you can do is tell the MAM
    what network segment types you want created and what backplane ports
    you want connected to each.
    
    If the configuration you request is possible given the signals
    accessible by each module, the MAM will compute an allocation that
    creates the topology that you want, but even then you can't tell which
    physical signals are being used for which segment.  
    
    The allocation order described in one of the earlier replies is an
    artifact of the capabilities of the current repeaters and _will_ change
    for configurations that will be possible with newer modules.
    

    
    I have a followup question concerning IMBs.  Is there any hope that we
    will be able to put more than 6 ethernets and solve the ADD FAILED
    problem any time in the future?
    
    Marc
    
    
    

    Quiver used to be part of the NETCAD cluster, so if you substitute
    "quiver" with "netcad", you should be able to get at the document
    you're looking for.
    
    Bob

    Bob, thanks for your prompt response. NETCAD is alive but the account
    seems to be protected as I can't dir into it. Do you know any other
    location for those specs ?

    No Patrick, I do not know. These are engineering specs, and as such
    need to be protected from general access. There is I believe
    an access control list for access to this area.
    I'd suggest you send mail to Rich Graham and inquire about access
    and state reason for your need.
    
    Bob