When you create a LUN, you can only access it with the iSCSI, FC, or FCoE protocol by default. However, you can use NAS protocols to make a LUN available to a host if the NAS protocols are licensed and enabled on the storage system.
The usefulness of accessing a LUN over NAS protocols depends on the host application. For example, the application must be equipped to understand the format of the data within the LUN and be able to traverse any file system the LUN may contain. Access is provided to the LUN's raw data, but not to any particular piece of data within the LUN.
If you want to write to a LUN using a NAS protocol, you must take the LUN offline or unmap it to prevent an iSCSI or FCP host from overwriting data in the LUN.
The LUN is now readable over NAS.