In-car Ethernet Enters the Road

With the current MOST150 rollout, the MOST Cooperation is adding the transmission of Ethernet protocol data to the established MOST infotainment transport of audio and video within the car, explained Dr. Christian Thiel, MOST Cooperation Administrator. Thus, the Ethernet Channel of MOST150 is equivalent to an IEEE802.x network. MOST150 combines Ethernet technology with a networking technology that was designed to meet the stringent automotive requirements. MOST provides the ideal network backbone for a broad variety of IP-based applications such as supporting apps on connected services and Internet access in general.

The MOST network technology is extremely flexible, allowing star, daisy-chain, tree, and other topologies implemented on different physical layers such as POF (plastic optical fiber) and electrical physical layers:

coax and shielded or unshielded twisted pair (STP/UTP) copper wires. The coax standard has recently been specified to serve other vehicle domains, i.e. it fits into the driver assistance domain, as this physical layer is able to provide bi-directional communication and power supply on the same cable.

Regarding content protection, HDCP (High-Bandwidth Digital Content Protection) has been added in addition to DTCP (Digital Transport Content Protection). With these, MOST fulfills the present and will fulfill foreseeable future copy protection requirements for upcoming rights management and copy control systems.

Bandwidth for Ethernet transport exceeds 100 Mbit/s

The MOST Ethernet Channel provides the necessary infrastructure to implement all necessary protocols and mechanisms such as the Internet Protocol (IP), the Transmission Control Protocol (TCP), or the Hypertext Transfer Protocol (HTTP) which are required to support Internet access in a distributed infotainment system. Simultaneously, MOST maintains other essential communication features, such as synchronous and isochronous channels for easy and efficient audio and video streaming. The MOST150 network provides an efficient and easy to use solution for transmitting IP traffic.

Investigations on the throughput with the maximum bandwidth allocated for the packet channel proved that a net bandwidth of over 107 Mbit/s can be achieved, showing that the maximum bandwidth of 142.8 Mbit/s can be utilized with efficiency of over 75 percent.