Conference netcad::hub_mgnt

    
    
    About 2)
    
    
    The idea behind the LIGO types in HW, it's to provide a set of valid
    configurations, each one representing one of the possible combinations
    for front panel ports 1 and 6 and backplane connections.
    
    So, each LIGO type represents the whole concentrator, when you take 
    the stub in HW, you are connecting the one or two ports connecting to
    the backplane depending on the selection made.
    
    Since "the concentrator is the building block for FDDI networks",
    in HW you make conections among concentrators, not ports.
    

    
    
    And for 1) there will be no problem, but if prefer,
     you can configure that port as port M
    
    
    Carlos Silva
    Digital Mexico
    

	The "FDDI backplane lan" doesn't equate to A or B or M or S. 
	All connections are point to point - if you have an A out the back
	then it is forced by the LIGO's in Hubwatch to connect to a
	B port on a neighbor module. The FDDI backplane lans are either 
	rings or trees - not a mix. 

	Read note #2340 for more info.

	-Mike

	re: .2
    
>    And for 1) there will be no problem, but if prefer,
>     you can configure that port as port M

	really? I can find nothing to indicate that the front panel
	FDDI ports on a DECbridge 900MX can be anything but A and B...
	I assumed that if A+B were configured to the backplane that the
	front panel ports would be inactive..........

	here's what I'm trying to do:

	I have a 900 hub with a number of DC900MXs and one DB900MX...all
	the DC900MXs are currently configured with A+B as backplane ports
	and the S port of systems with SAS adapters connected to the front
	panel M ports...the DB900MX is currently configured with A+B
	as backplane ports and one 10BT port on the front panel connects the
	hub to the rest of the network...all modules in the hub are connected
	to an FDDI backplane LAN segment, and I now gather that this
	is essential a virtual dual ring...

		- is this configuration correct so far?
		- is there a better/other way to configure it? for
		  example as a virtual single ring? advantages/disadvantages??

	can I now connect another SAS adapter's S port to anything on the
	front panel of the DB900MX? if not, would some other configuration
	allow me to do so???

	_kelley    

	I posted .4 will and then saw .3...I will read the doc and
	see if it answers my questions...

	thanx
	_kelley

	ok, the doc pointer in .3 was very helpful...I can now talk
	I hope more intelligently about this...

	first, its clear to me I need to install wave 3 firmware...that's
	why I haven't seen the option to make the external ports on
	the DS900EF (yes: I now know I should no longer be calling this
	a DB900MX ;-) a PHY M....so I'll get off my butt and install the
	stuff in the DEChub CFW V4.0 kit, and get HUBwatch V4 et. al....

	with that in mind, is the following a legal FDDI tree config?

				Front Panel Ports

	  M M M M M M      M M M M M M      M M M M M M                M  
	  | | | | | |      | | | | | |      | | | | | |                |  
	+-+-+-+-+-+-+-+  +-+-+-+-+-+-+-+  +-+-+-+-+-+-+-+  +-----------+-+
	|   DC900MX   |  |   DC900MX   |  |   DC900MX   |  |   DS900EF   |
	+-+---------+-+  +-+---------+-+  +-+---------+-+  +-+-----------+
	  |         |      |         |      |         |      |           
	  |         +      +         +      +         +      +           
	  S         M------S         M------S         M------S           

				Backplane Ports

	in all cases, front panel PHY M ports will be connected to PHY S
	ports of SAS adapters in Alphas...

	if this is legal, is there anything special I need to do either
	in ordering the modules in the DEChub slots or in ordering how
	I drag the backplane ports to the backplane LAN interconnect, or
	does HUBwatch and/or the hub itself figure out which port should
	be used to connect to its neighbor?

	thanx for the help so far...

	_kelley

    
    Yes, this is legal. You can place the modules anywhere you want in the 
    hub. You then create the FDDI LAN with Hubwatch, configure the LIGOs,
    and pull them down to the FDDI LAN ICON. The MAM will connect them in 
    the backplane as described in note 2340. 

	thanx for all the help

	_kelley

    I see you are very concerned about the placement of 
    modules and details like that, just a recomendation about 
    the order of connections of modules:
    
    When you connect modules in HW remember to connect first 
    adjacent modules. 
    
    The structure of the backplane channels is like this:
    
                  1 2 3 4 5 6 7 8  (structure of modules)
                  ---------------
                  ---------------
                  ---------------
                  ---------------  (10 flex channels covering all slots)
                  ---------------
                  ---------------
                  ---------------
                  ---------------
    
                  ------- ------- (4 flex channels covering a half of all
    slots)
                  ------- -------    
    
    If you connect something like 4 DC900MX in slots 1, 3, 5 & 7 and
    connect
    first 1 and 7, you are using 1 of the 10 "complete flex channels". 
    But if you connect 1 to 3 instead, you are using one of the split
    channels
    at the bottom, reserving the "complete" channels for other actual or
    future uses.
    
    Conclution: First connect the adjacent modules to take advantage of the 
    split channels in the backple.
    
    "Adjacent" meaning "in the same group of 4 slots sharing a split
    channel"

    
    re .9
    
    Actually, the order of connection is not something you need to
    keep track of. Hubwatch will allocate the channels in the optimum 
    mmanner so that you (the user) do not have to worry about all of this. 
    You are correct about the types of things that are at issue, but
    they are hidden from the users.