Start a Conversation


This post is more than 5 years old



March 21st, 2011 04:00

Ultra felx technology and ALPA in CX-4 series

In CLARiiON CX-4 series; ultra scale technology which implements ultra flex point to point connection.

I can not understand the exsitance of such term in the CX-4 series, and the existance of ALPA (Arbitrated Loop Physical Address) !!

I'm confused with the co-existance of the two terms or the two technologies inside the CX-4 series!!

March 29th, 2011 09:00

Hello Shawky,

Although I expect it would be less common, the Cx4 does support direct attach to a host (as opposed to attach via a fabric switch). This would be called Private Loop Direct Attach - the front end Fibre Channel topology would be private Arbitrated Loop. Both the initiator and the target would have a fibre channel node type of 'NL' (meaning Node Loop).

In contrast, if you do connect via a switch, then the Fibre Channel topology would be Fabric Point-to-Point; in this case the initiator would have a Fibre Channel node type of 'N', and would connect to an 'F' port on the switch (from previous conversations, I know that you understand this, but, for completeness, an 'F' port is a port that provides access to fabric services).

Now, I have never worked on a direct-attached Cx4, however, the following command is documented as displaying the Arbitrated Loop Physical Address (private) of the front-end storage target 'NL' Port:

  • naviseccli -h alpa -get

I hope that helps.

Thanks, Richard.

16 Posts

April 6th, 2011 01:00

Hi Richard,

I really get your point about the environment in both cases the Direct connection and the switched connection.

But after revising the internal structure and the connectivity scheme of the backend loops in CLARiiON, i think im looking for something internal not about the connectivity options between host and storage.

However your explanation was very good about the connectivity scheme and having the bigger picture  ....



No Events found!