Abstract: A vehicle subsystem assembly transmits an identifier of the vehicle subsystem assembly to an electronic control unit (ECU) via an Ethernet link as part of a procedure for obtaining a first key for secure communications with the ECU via the Ethernet link from a backend system. Then, the vehicle subsystem assembly receives an encrypted message from the ECU via the Ethernet link and decrypts the encrypted message using a second key stored at the vehicle subsystem assembly to generate a first decrypted message. The vehicle subsystem assembly determines whether the first decrypted message includes a second identifier that matches the first identifier, and extracts the first key from the decrypted message. In response to determining that the decrypted message includes the second identifier that matches the first identifier, the vehicle subsystem assembly uses the first key in connection with secure communications between the vehicle subsystem assembly and the ECU.

Abstract: A network interface device operates in a normal transmit operating mode in which the network interface device continually receives transmission symbols from a link partner via the communication link. The network interface device determines that receive circuitry of the network interface device is to transition to a low power mode in response to receiving a sleep signal from the link partner. The network interface device then operates according to a quiet/refresh cycle of the low power mode to conserve power. The quiet/refresh cycle corresponds to a time schedule that includes a refresh time window in which receive circuitry of the network interface device is to be powered to receive a refresh signal from the link partner Immediately after transmission of the sleep signal, the network interface device transitions to a quiet time window of the time schedule in which the network interface device ignores transmissions from the link partner.

Abstract: A network communication system having at least two communication protocol modes, namely, a full power communication mode and a low power, limited communication mode. In the low power mode, the link is line powered and utilizes link pulses to represent binary 1s and idle line states to represent binary 0s so that low power mode communication is entirely compatible with all 10BASE T equipment on the network.