I'm having issues designing an architecture for communication in a vehicle. Currently a PC is connected through a switch to a series of ECUS, each one with a TCP2CAN converter. The PC has to be started prior to the ignition of the vehicle, which is the main issue, in order to keep the watchdog of the master ECU alive.
I'm searching for solutions to do this in an automated way, meaning vehicle's ignition, turns on a device (call it PLC or Microcontroller) which is able to handle this TCP messages (RAW) and send them to their correct destinations This implies timing limitations in the system, to keep watchdogs alive.
I've found multiple PLCs with Modbus TCP IP protocol, but I'm unsure whether this is equivalent to TCP/IP. I've also search in other questions and answers, but most of the TCP/IP questions refer to a stack in a microcontroller. I'm open to other solutions (not necessarily a PLC), as long as I am able to work as a gateway to interact with TCP/IP messages (read them and modify them accordingly).