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February 21st, 2013 21:00

What is the "NP" director bit settings meaning?

What is the "NP" director bit settings meaning?

As per Primus emc66020

If the NP (Non-participating) flag is enabled and the H-bit is set (H is on by default and not visible), the director uses only the hard address. If it cannot get this address, it re-initializes and changes its state to non-participating (goes offline). If the NP-bit is not set, the director accepts the soft-assigned address.

What's the function of H-bit and what's different between hard address and soft-assigned address.

Thanks,

June

2 Intern

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467 Posts

February 21st, 2013 21:00

When two NL ports are connected in the fabric the loop initilization process starts to assign an AL_PA (Arbitrated loop physical address" to each NL port. If the port has previousy acquired an AL_PA then it will try to keep it,  but if it cant it will either get assigned a new one or be set to NP (non participating) mode - which in effect disables it.   By default it will accept the new AL_PA,  unless the port is set to NP enable.

You've got another bit in the mix called the Loop ID which is a one-byte address (00 - 7D). If the H Bit is set thie Loop ID is what the FA will try to get it's AL_PA based on this Loop ID.   If it gets it it's called a Hard Address.  If it doen't it will either accept the Soft Address (if the NP is not enabled) or reject it (if enabled) and enter into a disabled like state.

To recap... when your FA is connected to a switch port...  it's going to get assigned an loop address.  It goes something like this:

Connection made

Check H Bit

H Bit enabled -> use the LOOP ID to get the address (hard address)

     Address accepted and assigned using Loop ID -> Open for business using hard address

     Address not assisnged using Loop ID -> Check NP Bit

         NP Disabled -> Accept soft address -> open for business using soft address

         NP Enabled -> Reject soft address and go offline

H Bit disabled -> accept the assigned addres (soft address)

Hope that makes sense its late for me..

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