Methods and systems for Ethernet fabric protection in a disaggregated OTN switching system that include PIU modules each having multiple ports for OTN to Ethernet transceiving and an Ethernet fabric as a switching core are disclosed. An OTN over Ethernet module in each of the PIU modules may enable various OTN functionality to be realized using the Ethernet fabric which may include multiple Ethernet fabric planes. A PIU module may transmit Ethernet packets using a first working port over a first Ethernet fabric plane and may transmit Ethernet packets using a second working port over a second Ethernet fabric plane. When the PIU module detects a fault condition on the second Ethernet fabric plane, the PIU module may transmit Ethernet packets using a third protection port over the first Ethernet fabric plane instead of using the second working port.