Fa network lsi and communication device

A communication device used in an FA system in which a plurality of communication devices are connected via a network, and capable of performing a communication process in a network layer or higher through a plurality of protocols, the communication device comprising:

• a physical-layer processing unit that performs a process in a physical layer for control data with the network;
• a function processing unit that performs a predetermined process using the control data;
• and
• an FA network LSI provided between the physical-layer processing unit and the function processing unit so as to perform a process in a data link layer and a process in the network layer or higher for the control data wherein
• the FA network LSI includes
• a data-link layer processing unit that performs the process in the data link layer for the control data, and
• a protocol processing unit that performs the process in the network layer or higher for the control data,
• the data-link layer processing unit includes
• a first data-link layer processing unit that performs a first data-link layer process in the data link layer defined dedicatedly to correspond to a protocol for which high speed processing is required,
• a second data-link layer processing unit that performs a second data-link layer process in a standard data link layer for a protocol other than the protocol for which the high speed processing is required, and
• a data-link-layer-processing selection unit that selects one of the first data-link layer processing unit and the second data-link layer processing unit in accordance with a predetermined criterion for transmitted control data or received control data, and wherein
• the data-link layer processing unit is formed by hardware.