You don't need the iPockets, the 3300 can put out the data on the existing network interface you're already using. Data admin just needs to enable routing between the subnets so the PMS server can actually connect to the 3300 and see the data streams.
Now if for some reason they don't want to enable routing between the subnets and instead want to keep the 3300 subnet completely walled off (doesn't make sense but I've still seen it happen), then yes, you would use the iPocket and put its Ethernet port on the same subnet as the PMS server.