Abstract: A vehicular data tunnel Thin Client Unit (TCU) apparatus includes a circuit to couple onto an Internet Protocol (IP) secure Ethernet transitory data communication medium. A circuit can transform and reverse serial data frames into and out of Internet Protocol packets including an encrypted IP packet. It includes a circuit to dispose of CAN data frames which are inconsistent with any mission of locally attached CAN or LIN compatible devices. The method of operation includes: receiving and dynamically installing configuration data to connect to an Ethernet medium as a terminus or as a relay in a ring, subscribe to a Intranet Vehicle Private Network, determine Quality of Service priority and recipient identification, receive and transform LIN and CAN data frames to IP packets, encrypt and decrypt packets for transmission, and conduct sender verification and data frame consistency.