Explanation/Reference:
Excerpt from TechNet:
For each cloud, the Fabric Health Dashboard displays these aspects of the fabric:
Host State: monitors the health state of the hosting groups or the computing aspects of the cloud, such as CPU, memory, disks, and network adapters Storage Pools State File Share and LUN State: monitors the health state of the storage aspect of fabric for issues, such as disk space capacity and allocation Network Node State: utilizes network monitoring in Operations Manager and displays the health state of network nodes (devices) that are relevant for the cloud you selected. Only physical network devices within one hop from the hosts are shown. To see the physical network devices, you must enable the Network Monitoring feature of Operations Manager and monitor the physical network devices connected to the hosts. Virtual networks are not shown in the dashboard.
References:
http://technet.microsoft.com/en-us/library/dn249700.aspx