The MOST Specification Rev. 3.0 is a complete overhaul of the MOST (Media-Oriented Systems Transport) specification for automotive infotainment systems. The revision, released by the MOST Cooperation, an organization of 16 auto manufacturers and more than 75 component suppliers, is independent of speed grade and can already work with the newly defined MOST150 physical layer.
Thus Rev. 3 allows a higher bandwidth of 150 Mbits/s. It also includes an isochronous transport mechanism to support extensive video applications and an Ethernet channel for efficient transport of IP-based packet data. A typical use for the isochronous channel is the transport of MPEG streams, since they generally use a variable bit rate. The Ethernet channel can transport unmodified Ethernet frames according to IEEE 802.3. This permits software stacks and applications from the consumer and IT domain.
Rev. 3.0 incorporates several “lessons learned,” mainly driven by the experience of MOST Cooperation’s Compliance Verification Program. Emphasis has been put on clear specification points where conformance can be easily verified during compliance testing. Diagnosability has been optimized by an overhaul of Ring Break Diagnosis behavior as well as Detection of Sudden Signal-Off. The robustness of the procedures was verified during the early phase of the specification by using Failure Mode Effects Analysis (FMEA) as well as reference implementations through virtual prototypes.