ABSTRACT
Master-Slave Structure <MS) Master-slave structure in distributed control system is mostly used. Master-slave structure is easy to form and also master-slave protocol has been widely available by many companies \6\,\7\,\8\. In hierarchial system it is usually uncontrollable situation if master will be broken. So, masterbased control systems depend strongly on one node. Thinking about security this can be an additional risk. Needed number of transmission for updating all nodes is in host based system two times the number of nodes. The problem is that all processing that handle the control of whole machine have to be executed in one node, and that the same node have to control also the message sending in the system. So the clear bottleneck in the system is then the master. Parallel processing can be used only partly with host based architecture.
