The ring topology

A MOST bus system has a ring shaped structure:

The data is passed from one control unit along to the next one. If a data packet comes back to the control unit which first sent it (initiated it), the ring is closed. This guarantees that every control unit receives the data packet.

There are two connected control units with special functions:

• The system manager controls the system conditions, manages the transmission capacities and sends messages to other systems. Thus it has a Gateway function within it.
• The diagnostic interface enables the connection of diagnostic devices.