Clarification - Onboard Administrator enclosure link cabling

[chuckk281]

Angel had a customer question regarding the linking of the Onboard Administrator modules:

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Hello all,

I’ve been asked to clarify what is the best practice of linking the OAs of multiple enclosures.  One

suggestion was that a loop needed to be created between the enclosure down link port of the last

enclosure to the enclosure link-up port and service port of the first enclosure. 

The HP BladeSystem c7000 Enclosure Setup and Installation Guide has two notes which appear

to contradict each other regarding the top enclosure link-up port.

NOTE: The enclosure link ports are designed only to support c-Class enclosures in the same rack.

The enclosure link-up port on the top enclosure is the service port, and the enclosure link-down port

on the bottom linked enclosure is unused. [Sic implies no bottom to top connection]

NOTE: If more c-Class enclosures are added to the rack at a later time, the open enclosure link-up

port on the top enclosure can be used to link the new enclosure.

What is the correct way to link multiple enclosures/OAs?  If a loop is created, what are the

ramifications?  Thanks in advance.

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Monty was on top of it:

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The enclosure link ports are used by the OA to determine topology – the enclosure at the top of the stack is the top enclosure in the GUI view of linked enclosures.

Yes – an additional use of the enclosure up link port is as a service port – to connect to a PC Ethernet port.

Do NOT loop the top enclosure to the bottom enclosure – this loops the OA enclosure link network and there is no end to the topology chain.

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Comments? Other suggestions? Good to go?