Solved: Unique Area FC IDs for HBAs

emcprateek_2 · ‎09-26-2009

When HBA port and the storage port are connected to the same switch. Some HBA ports require a different area ID than storage ports when they are both connected to the same switch. For example, if the storage port FC ID is 0x6f7704, the area for this port is 77. In this case, the HBA port's area can be anything other than 77. The HBA port's FC ID must be manually configured to

be different from the storage port's FC ID.

Can someone elaborate on which specific/host storage vendors referred here. Any insight on this behavior would be helpful.

Reference: MDS CLI Guide (Text Part Number: OL-16484-02) - Page 18-17

Gary Ross · ‎09-26-2009

I found this and I'm wondering if the last part might be te answer you're looking for.

I'm assuming that everyone knows what an FCID is (Domain ID, Area ID, and Port ID). I'll expand on the Area ID for this question.

An Area ID is used to identify groups of ports within a domain and are also used to uniquely identify fabric-attached arbitrated loops. Each fabric-attached loop receives a unique Area ID.

It is this last part that I think is the answer you're looking for. So if you have point to point devices in say VSAN 100 and an arbitrated loop with devices in the same VSAN, you might see this scenario.

Gary

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Gary Ross · ‎09-26-2009

I found this referenced when dealing with Datacore Storage Servers.

ftp://support.datacore.com/psp/quallists/SWITCH_ALL.pdf

This is the only one I could find. Great question. You had me scratching my head as to why this would matter. I've always thought that as long as I have unique FCID's, who cares.

Hope this helps.

Gary

emcprateek_2 · ‎09-26-2009

Thanks for the insight. That did help.

I believe the scope of this limitation must be very limited.

It would be great if someone could identify on how the area is is playing a role in connectivity here.

-Prateek

Gary Ross · ‎09-26-2009

I found this and I'm wondering if the last part might be te answer you're looking for.

I'm assuming that everyone knows what an FCID is (Domain ID, Area ID, and Port ID). I'll expand on the Area ID for this question.

An Area ID is used to identify groups of ports within a domain and are also used to uniquely identify fabric-attached arbitrated loops. Each fabric-attached loop receives a unique Area ID.

It is this last part that I think is the answer you're looking for. So if you have point to point devices in say VSAN 100 and an arbitrated loop with devices in the same VSAN, you might see this scenario.

Gary

emcprateek_2 · ‎09-27-2009

That does make sense. In case the area id for a point to point device was same as the the area id for the AL devices the PA range (00->FF) of the devices in the loop for the same ares will also include the p2p device.

Thanks Gary!!

Michael Brown · ‎09-28-2009

As I recall, this is a Qlogic (and their re branded HBAs) issue. Emulex HBAs do not have this issue. I think it stemmed from the early days of FC, when the vendors used the port number on the switch as the area portion of the FCID. When you trace the connection, you see the HBA Flogi, then register with the name server, then query the name server for devices in the same zone. For some reason, it never sends Plogi to any devices with the same area. Cisco developed the unique OUI feature as a bypass to the issue. If the MDS detects a Qlogic OUI at Flogi, it will be given an FCID with a unique area. You also have the ability to add additional OUIs as needed if you happen to hit this issue and the OUI is not included in the MDS firmware already. If you want to see which OUIs the firmware has included for unique area assignment, issue this command from the CLI "show fcid-allocation area"

Hope this helps,

Mike