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How to create FCIP link without merging the fabrics.

Abhi Varada

We have two data centers about 200 miles apart and have individual SAN fabrics at both locations. We recently installed a 300Mbps IP WAN between the locations to setup Replication. I have created an FCIP link and tunnel but the problem is, now both fabrics are merged. The VSANS themselves are isolated (because we have only allowed the replication VSAN through the FCIP tunnel)  but the device-aliases across all vsans are all merged. I mean device-aliases which have been created on either fabrics now have been merged to both the fabrics now and DCNM sees switches from both the Data centres as one huge fabric now. I am not sure how to separate the fabrics. I atleast want the device-alias databases separate from each other. Any help is much appreciated. 

6 Replies 6




If you don't want the VSANs to merge, disallow that VSAN from the trunk. If you want to communicate them, you can create a transit VSAN and use IVR.



Hi. Thanks for the reply. I have created a transit vsan and disallowed all other VSANS from the trunk. So, all other VSANs except the transit VSAN are isolated but all switches in both locations still show up as one fabric. And also, because device-aliases are global across vsans, all the device-aliases have been distributed across both fabrics. So, I was wondering how to separate the fabrics, and manage them separately while still having an FCIP link between them. I haven't used IVR though. The reason for that is that we have a transit VSAN 98 in both fabrics. So didn't think IVR was necessary.

I would recommend you have a look at

In your case IVR is mandatory ! and for any FCIP network recommended.

Be aware that

Not every MDS supports IVR (I think N5K either)

IVR applies a different type of zoning, called IVR zoning

I believe IVR zoning doesn't support fc-alias, nor device-alias, only pwwn based

In case you share same VSAN in either datacenter, and domain-id's are not unique, you need to configure NAT as well

IVR is tricky, and requires careful planning; operations is challenging as well; you most likely have local zones as well as IVR zones / zonesets


IVR NAT is the only supported option since 5.2.x


The domain ID's are unique in my case. Should I still configure NAT? Is there an advantage to it?

NAT is no longer supported, regardless if you have unique VSAN IDs or not.

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