MOST Forum sketches 5-Gbps future

April 26, 2013 // By Christoph Hammerschmidt
At the recent MOST Forum in Esslingen near Stuttgart (Germany), experts discussed the presence and future of the MOST data bus used in automotive environments. Against the background of the AVB/Ethernet camp seemingly having gained ground recently, the MOST proponents mulled the specifications of the next MOST bus generation MOST bus. Key parameters for the 5Gbps optical data bus already take shape.

In a joint presentation of Daimler and the FZI research centre, Wolfgang Franz from Daimler and compared AVB and the current MOST generation, MOST 150. While the comparison covered many aspects, it boiled down to the deterministic nature of the MOST system versus the packet-based and thus not entirely deterministic behaviour of Ethernet-based AVB. Due to its deterministic nature, the MOST system offers better quality-of-service, concluded Franz. "Today, there is no better alternative to MOST150", he said. The expert however conceded that flexible topology options are needed to remain competitive.

This is something the next MOST generation will achieve. Besides legacy channels for today's MOST 150, MOST nG will offer enhancements to the current ring architecture in that will be possible to add elements characterized by a bus or star topology. The strong market position of AVB will it also make necessary to ensure maximum interoperability.

At the event the MOST group also introduced a number of enhancements to the existing MOST universe, including a HDCP scheme for the secure transmission of HDMO video data over MOST. This allows a MOST network to move, for example, HDMI content with the required degree of content protection. In this context, the MOST Cooperation has optimized the network for high-quality video streaming. Currently, MOST150 enables direct isochronous transport of, among others, MPEG video streams without bit-stuffing or transcoding. Now, the MOST standard supports approved content protection schemes for both Digital Transmission Content Protection (DTCP) and HDCP, thus enabling the digital transmission of DVD audio and video, HD-DVD, Blu-ray and HDMI content.

DTCP is used for the networked distribution of protected content and has been approved for MOST for many years. However, HDCP is used for a more direct point-to-point connection between the output of a data source and a renderer. HDMI requires HDCP protection. Data cannot be extracted from an HDCP system and moved with a different protection scheme. With this new specification,