Conference netcad::hub_mgnt

    
    Dan,
    
    	You have listed a limit of 4 DECrepeater 90FAs and 4 DECrepeater
        90FSs for a DEChub 900. I believe that the limit should be 8.
        What was the limit of 4 based on (ie power)?
        
        I believe that you can have 8 DECagent 90s in a DEChub 900 (using 
        power and net connectivity). These DECagent 90s could be used to 
        manage communities elsewhere on the network. It may not be a common 
        configuration though. Not sure on 2 DECagent 90s (slots 7 and 8) in a 
        DEChub 90.
    
    Regards,
    Bob

    
    			Maximum		Maximum
    			Allowed in	Allowed in
    Module		DEChub 90	DEChub 900
    -----------		--------------	----------
    DECagent 90		     2		     7  as need 1 slot for LAN
    DECbridge 90	     2*		     8*                  connection
    DECbridge 90FL	     2*		     8*
    DECrepeater 90C	     8		     8
    DECrepeater 90FA	     2		     8
    DECrepeater 90FL	     8		     8
    DECrepeater 90FS	     2		     8
    DECrepeater 90T+	     8		     8
    
    DECrepeater 900FP	     -		     8
    DECrepeater 900GM	     -		     8
    DECrepeater 900TM	     -		     8
    DECswitch 900EE	     -		     6#
    DECswitch 900EF	     -		     6&
    PEswitch 900	     -		     6&
    
    * - enough power to do this but not recommended due to possible
        configuration problems, ie. 200 address table limit.
    
    # - could have 8, but power supply limits it to 6.
    
    & - based on the DECswitch EF should be able to run at least 6 units.
        May be able to have 7 or 8 DECswitch EE's as they do not have
        an FDDI interface so will draw less power.
    
    Slots 7 & 8 in the DEChub 90 have the +12V that certain 90 modules
    require, ie. DECagent 90 and any module that has an AUI port.  There
    are no such restrictions in the DEChub 900 chasis.
    
    dave

    Thanks very much for your comments.
    
    I'm considering more than just power.  This should be a functional and
    supported configuration; therefore, only  1  bridge in each DEChub 90.
    Same for DEChub 900 with regard to the DECbridge 90 modules.
    
    However, when we get to the DECswitches and the PEswitch, what is are
    likely and workable configurations?
    
    Thanks,
    Dan

    If you ignore power limitations then 8 switches could be put into
    one DH 900MS and there would be no limitations why you couldn't.
    But power is a limiting factor with the switches and the numbers
    and my comments are valid, 6 or more switches depending on the switch
    and the amount of power drawn.

    dave

    A correction and some more info on the switch power numbers.
    
    	Option			Power		Modules Per Hub (*)
    	---------------		-----		-------------------
    	DECswitch 900EE		62.5W			6
    	DECswitch 900EF		67.5W			6
    	PEswitch 900TX		50.5W			8
    
    (*) This assumes there are 3 or 4 power supplies installed. If
    	4 then the fourth supply is only for redundancy.
    
    	The above numbers are strictly based on power usage. As pointed out
    in previous notes the actual useful configuration may yield a lower
    number of modules per hub. For instance, if one wanted to bring the
    FDDI out of the backplane with a hub full of PEswitch 900TX's you would
    have to install a Wiring Concentrator in one of the slots, thus taking
    away one of the PEswitches.
    

What about the remaining modules? Where can we get similar power re-
quirements for all the HUB90/0 modules?

pellis.

    
         See note 4. By the way this note is one of several in the tagline
    when the conference is opened so that you don't have to do a serch to
    find the information.
    
    

    A comment in regards to .2
    
    The DECagent90's front connector is NOT an AUI-port, but a simple
    terminal-port for console managment. Elswhere in this notefile I
    noticed reference to a DC-DC converter used in this module, so it almost 
    looks as if this module doesn't necessarily have to reside in slots 7 or 8 
    of the DEChub90.
    
    Anyone know for sure?
    
    Rolf 
    DC_Brazil
    
    

    
    Rolf,
    
    	The DENMA must reside in either slot 7 or 8 of a DEChub 90, any
        slot in a DEChub 900, or can be standalone. The port on the
        front of the DENMA is for either a console port or an OBM/SLIP
        port.
    
    Regards,
    Bob

    Bob, 
    
    OK, so I presume that OBM/SLIP port does in fact require the 12 volts
    from the backplane.
    
    Now, if I were NEVER to use that port, could I then place the agent in
    any of the other 6 slots?
    
    I'm asking this because I have a customer who has 4 hubs, each with a
    Bridge90 and a 90FA and wants to avoid having to use the Agent free-
    standing.
    
    This also brings up the academic question: Could I use a 90FA or a
    bridge90, on which I don't use the AUI port, in any of the remaining 
    slots?
    
    I know, I know, we shouldn't sell this kind of configuration, but the
    customers are getting smarter all the time and want to know "just in
    case..."!
     
    I think I have seen this brought up in the conference before but I
    couldn't find it.
    
    Thanks
    Rolf

    
    Rolf,
    
    	I've used the DR90FA (fiber port only) in slots other than 7 or 8
        in a DEChub 90. I don't think that the DENMA or DECbridge 90 will
        function outside of those slots, but I'll yield that to the
        experts:-) Personally, if all the LEDs don't come up as expected
        (which they don't with the DR90FA in the lower 6 slots), I'd
        shy away from it. 
    
    Regards,
    Bob

You cannot use a DENMA in any slot except 7 or 8 in a DEChub 90.  The flash RAM
on board requires +12V.  Since the functional firmware runs out of the flash,
you're SOL without +12V.  The db25 connector on the front panel also uses +12V.

I don't have the schematics or specs for the DECbridge 90/90FL, but for sure the
AUI needs +12V.  I'm not sure about the other components, but my guess is that
something else needs +12V since it will not pass self-test if it is not in slot
7 or 8 (in fact, the Power OK LED does not even light up).

The DECrepeater 90FA will repeat out the fiber port if installed in any slot. 
But as Bob suggested, this configuration is not recommended as the AUI port will
not operate unless the repeater is installed in slot 7 or 8.

...Roger...

    OK thanks,
    
    with this precise info it will be easy to talk to the customer!
    
    Regards - Rolf