Ethernet enters infotainment domain - on the back of the MOST bus

March 21, 2012 // By Christoph Hammerschmidt
When these days the latest version of the MOST infotainment bus, MOST150, enters serial production, it also brings Ethernet to the infotainment domain. The reason: MOST150 contains a full Ethernet channel which meets the IEEE802.x standards.

Against the background of the OPEN Alliance's announcements to roll out their Ethernet PHY into cars, the MOST Cooperation at the MOST Forum this week highlighted that MOST150 already includes Ethernet. While however the OPEN Alliance's roadmap provides for Ethernet roll-out in serial production only in several years, with MOST150 Ethernet is available in vehicles now. "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," said MOST Cooperation Administrator Christian Thiel. "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."

Indeed, the MOST network technology is very 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 as well as shielded or unshielded twisted pair (STP/UTP) copper wires. The coax standard has recently been specified to serve other vehicle domains - in particular 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. In order to meet the copy protection requirements rights management systems for digital high-resolution video entertainment applications, the MOST Cooperation has added HDCP (High-Bandwidth Digital Content Protection) in addition to DTCP (Digital Transport Content Protection).

The Ethernet Channel within the MOST network provides the infrastructure to implement the 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 audio and video streaming. Independent investigations on the throughput with the