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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

848.0. "Hub Manager Question" by ALBANY::BARTLEY () Tue Mar 22 1994 10:10

    Customer question:
    
    If the Hub Manager (that module in the top of the 900MS) dies, will
    the hub continue to function?
    
    Thanks,
    
    Dave

T.R	Title	User	Personal Name	Date	Lines
848.1	Hub Manager answer	SLINK::HOOD	I'd rather be surfing	`Tue Mar 22 1994 10:43`	1
	Yes.
848.2	Yes, mostly...	QUIVER::SLAWRENCE		`Tue Mar 22 1994 11:10`	17
	That was perhaps a little too simple... Generally, yes, as long as you don't want to change the hub configuration and you don't power cycle things. Even after a power cycle, 90 modules will power up and just do the default thing and connect to the Thinwire (they do this without management intervention). Full height modules must have power enabled by the management module, and require instructions from the manager to connect to any backplane channel (some, including the DECserver900TM and the DEFMI will connect to the Thinwire by default). The management module is pretty easy to swap out (NOT hot swappable); the cover pops off and then there are a couple of nylon hold-down screws and two ribbon cables to remove and reconnect. If a customer is concerned about this and has enough hubs to justify it, they may want to stock thier own spare.
848.3	no full height module will start ???	ZUR01::SCHNEIDERR		`Thu Mar 24 1994 15:17`	22
	> Full height modules must have power enabled by the management > module, and require instructions from the manager to connect to any > backplane channel (some, including the DECserver900TM and the DEFMI > will connect to the Thinwire by default). Lets assume, after a powerfail the HUBmanager module died. That means, that no full height module (and in the future the new half height module, too) that has power management, won't start ??????? > The management module is pretty easy to swap out (NOT hot swappable); > the cover pops off and then there are a couple of nylon hold-down > screws and two ribbon cables to remove and reconnect. If a customer is > concerned about this and has enough hubs to justify it, they may want > to stock thier own spare. I heard that it will be hot swappable in the future. Is that true? Could someone explain, what configuration is where stored. For example if i have to swap the management module, all infos about channel are lost? Roland
848.4		NACAD::HERTZBERG	History: Love it or Leave it!	`Thu Mar 24 1994 15:25`	6
	All full-height modules have power management and need to be explicitly turned on by the hub manager. If the hub manager fails, all full-height will not power up. All half-height modules, new or old, power up without intervention of the hub manager.
848.5		QUIVER::SLAWRENCE		`Mon Mar 28 1994 10:06`	14
	.-1 is correct re: power up after manager failure. There is discussion of hot swappable managment for some future hub, but don't look for it soon - it is still just discussion. Basically, any configuration information for the hub as a whole, including backplane configuration is stored only in the management module (any other alternative would require arbitration between modules, which may have no means of even communicating with each other). So yes, if you loose the management module you loose backplane configuration. HUBwatch is looking at mechanisms for storing hub configuration information so that it can be easily restored, but this is not in V3.X.