function Get-ObservedIPRange {
	param(
		[Parameter(Mandatory=$true,ValueFromPipeline=$true,HelpMessage="Physical NIC from Get-VMHostNetworkAdapter")]
		[VMware.VimAutomation.Client20.Host.NIC.PhysicalNicImpl]
		$Nic
	)

	process {
		$hostView = Get-VMHost -Id $Nic.VMHostId | Get-View -Property ConfigManager
		$ns = Get-View $hostView.ConfigManager.NetworkSystem
		$hints = $ns.QueryNetworkHint($Nic.Name)

		foreach ($hint in $hints) {
			foreach ($subnet in $hint.subnet) {
				$observed = New-Object -TypeName PSObject
				$observed | Add-Member -MemberType NoteProperty -Name Device -Value $Nic.Name
				$observed | Add-Member -MemberType NoteProperty -Name VMHostId -Value $Nic.VMHostId
				$observed | Add-Member -MemberType NoteProperty -Name IPSubnet -Value $subnet.IPSubnet
				$observed | Add-Member -MemberType NoteProperty -Name VlanId -Value $subnet.VlanId
				Write-Output $observed
			}
		}
	}
}

# Example use:
# Get-VMHost esx01a.vmworld.com | Get-VMHostNetworkAdapter | Where { $_.Name -eq "vmnic1" } | Get-ObservedIPRange

# Example output:
#Device                 VMHostId               IPSubnet                               VlanId
#------                 --------               --------                               ------
#vmnic1                 HostSystem-host-102    10.91.245.128-10.91...                   2907
#vmnic1                 HostSystem-host-102    10.91.244.133-10.91...                   2905
#vmnic1                 HostSystem-host-102    10.91.243.253-10.91...                   2903
#vmnic1                 HostSystem-host-102    10.91.246.11-10.91....                   2908
#vmnic1                 HostSystem-host-102    10.91.246.129-10.91...                   2909