Ring ID to be assigned to the Ethernet segment.
Valid ring-id is from 0x001(1) to 0xFFF(4095).
Users can set EthRingID from 1 to 4095. But for 0
which is read-only, is not avaliable for user to set.
If 0 is returned (from GET), meaning SRTB is OFF,
hence not available for users to configure.