ISL trunking and interoperability mode

[Howard_24]

I hope to merge a fabric that consists of a SAN Switch 2/16 E/L with an C-class blade switch and a IBM Blade 2-port Qlogic switch. I also would like to enable ISL trunking on two of the ISL's between the C-class switch and the 2/16 E/L.

In order to merge the IBM Qlogic switch into the fabric I will need to turn interoperability mode to on. Will this cause me to not be able to trunk the C-class blade and the 2/16 E/L switch. Both of these switches are Brocade, but I need the interoperability mode for the IBM 2-port Qlogic switch.

I'm bringing this up because I saw that trunking doesn't support switch interoperability mode in the troubleshooting trunking problems. I will not be trunking to the IBM switch only between the two brocade switches.

Thanks,

Howard

[Peter Mattei]

I would not do that!!

If you need to present your IBM blades into the Brocade SAN I recommend using an FC router.
The FC router of choice would be the Brocade HP StorageWorks 400 Multi-protocol Router.

This will allow communication between dislike SANs without fabric merge!!

See the SAN design reference guide Chapter 3 on:
http://www.hp.com/go/sandesign
and the product page on
http://h18006.www1.hp.com/products/storageworks/400mpr/index.html

Cheers
Peter

[Howard_24]

This is a small SAN and with no SAN admin person and I don't know if putting in a router would be the best way to go.

Is this the only way I can get it to work? IBM's interoperability matrix states that the 2-port switch will work with the brocade switches, but they must be in interoperability mode. I just don't know if I will be able to trunk once I merge everything. Assuming that I can merge everything.

Thanks,

Howard

[Peter Mattei]

Well, as soon as you put the SAN in interoperability mode you will loose features like trunking.
You will still be able to do ISLs and the fabric will work.

As a reference see the "fabric merging inetroperability guide ..." on
http://www.hp.com/go/sandesign

Her you can see what you have to expect.

But at the end of the day IBM has to tell you what exactly will happen with their switch!!

Cheers
Peter

[Howard_24]

Peter,

Thanks, for your input. I read the link you gave me and it said that trunking is not support between the Mcdata or the cisco switches so I would assume that trunking would not work to the IBM (Qlogic) switches as well.

Since I only want to trunk between the two brocade swithes and not between the brocade and IBM switch shouldn't this work. We have only purchases licenses for the brocades.

Thanks again,

Howard

[Peter Mattei]

From my understanding you will not be able to do any trunking if in Interop mode, not even between Brocades.
In the manual it says:
Interoperating Fabric based on existing T11 standards documents > ISL Trunking not supported

However I have not tried it!

Please tell us when you are done!

Cheers
Peter

[Owen_15]

Hi Howard,

Just as a very quick side note to your discussion, I know you have purchased the trunking licenses for between your two brocade switches, but do you have the bandwidth requirement to justify trunking?

Trunking has it's place especially in large SAN's, but from the sounds of things, your SAN is quite small. Trunking only assists in improving the performance of isl links when there is a large bandwidth requirement and they are being flooded.

You can get some very simple performance metrics directly off the web interface of the brocade switches. You will be able to have a look at the ports that you currently have trunked and see what their utilisation is. It wouldn't surprise me if your port utilisation on the trunk ports is below 10% or even lower.

If it is below 10%, and you want to add that IBM switch into the fabric, I would go ahead with it. Turning on inter-operability mode and disabling trunking. Perhaps you can redeploy those trunking licenses?

Regards
Owen

[Howard_24]

The client purchased the trunking licenses before I got involed. I have been tasked to help get a design that would be easy to manage going forward. The IBM Qlogic switch has been the issue. I'm looking into replacing the IBM Qlogic switch with a pass-thru solution. I would plug the IBM blades into free ports on the 16 E/L and use the trunking licenses between the 4/12 on the C-class blade to the 2/16 E/L. The hp C-class has additional ports available so if they need to add a new EVA in the future they will be able to connect it directly into those switches and the IBM blades can get to the storage through the 2/16 E/L. I believe they want to expand the hp blades and slowly phase out the IBM blades so I'm not as concerned with performance on the IBM side.

Thanks,

Howard

[Peter Mattei]

This makes perfect sense.
If they still need more ports they can then either add another exetrnal B-series switch or by an upgrade license for the c-class blade switch (from 4/12 to 4/24)

Cheers
Peter