Control of ethernet link-partner GPIO using OAM

An in-vehicle Ethernet communication system, comprising:

• a first Ethernet Physical layer (PHY) device comprising (i) a first interface configured to connect to a first controller and (ii) multiple first General-Purpose Input-Output (GPIO) ports;
• and
• a second Ethernet PHY device comprising (i) a second interface configured to connect to a second controller and (ii) multiple second GPIO ports,
• the first and second Ethernet PHY devices being configured to:
• transfer data between the first and second controllers by (i) communicating with the first and second controllers via the first and second interfaces and (ii) transmitting and receiving, over a physical Ethernet link between the first and second Ethernet PHY devices, layer-1 Ethernet frames that carry the data;
• and
• transfer a multi-bit value comprising multiple bits, from a state encoder to a state decoder, using the same first and second Ethernet PHY devices and over the same physical Ethernet link used for transferring the data between the first and second controllers and independently of the first and second controllers, by:
• receiving the multiple bits of the multi-bit value from the state encoder on the respective multiple first GPIO ports of the first Ethernet PHY device;
• sending the multiple bits of the multi-bit value from the first Ethernet PHY device to the second Ethernet PHY device, over the physical Ethernet link, in an Ethernet Operations Administration and Maintenance (OAM) frame that is interleaved among the layer-1 Ethernet frames;
• and
• outputting the multiple bits of the multi-bit value to the state decoder on the respective multiple second GPIO ports of the second Ethernet PHY device.