AL_PA of a HBA

[vladimir_1]

How could I change an AL_PA of HBA (A3740A, A5158A)?

Thanks

[David Navarro]

Reestarting server ??? that is, shutdown, powering off and starting.

Maybe I'm wrong, but this address is assigned when you inserts a new node in AL, addresses are reassigned. If you power down HBA, you forces to be reinserted in loop.

Good Luck

[Oliver Haensel]

Hello Vladimir,

there's no need of changing ALPAs for HBAs.

The ALPA (arbitrated loop physical address) is the equivalent of the loop ID. ALPAs are used for routing FC frames within a loop. (this applies to the A3740A HBA).

There are 2 ways: hard coded ALPAs are used for storage devices (tapes, disks). One must ensure that these are unique in the loop. With HP-UX the ALPA/Loop ID determines the ioscan hardware path and therefore the device file.

If you don't need hard coded ALPAs you can let the fibre channel protocol select the ALPAs in the loop. Usually HBAs are not visible in ioscan therefore the ALPA is assigned during loop initialisation.

If your HBA is connected with fabric topology (A5158A: direct fabric attach or public loop) it will address with a 24Bit NPort ID.

When using Brocades native addressing mode (which is the default) the ALPA is part of the NPortID.

Hope this anwers your questionj

-Oliver-

[vladimir_1]

Hi Oliver,

Then how can I let or forbid assigning ALPA to an HBA with LIP?

[Oliver Haensel · Accepted solution]

Hello Vladimir,

there's no way - if you're connected in a loop.
So if you're using a A3740A HBA which is only capable of private loops you will get a soft assigned address every time a LIP occurs. This is part of the LIP (loop initialisation primitive) process: If a LIP occurs all previously assigned addresses will remain the same, that means the HBA will get the same ALPA again. Only if the server is rebooted the loop master can't remember the old ALPA...

But you can prevent getting new ALPAs...
Use a A5158A HBA which is fabric capable and connect it to a switch (i.e.Brocade). The host will automatically connect as N Port - a point-to-point topology with fabric login (means 24Bit address space). Then there will be no ALPA anymore... and no LIP too!

-Oliver-

[Surekha]

Hi all,

Is it possible to connect through Fibre Channel HBA directly to the optical disks in point-to-point mode. I don not want to use a Switch or Hub.

I have made set-up this way, but the port status is always OFFLINE.

Pls help me solve this problem.

thanks,
surekha