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1.3 Communication Protocol

The MELSEC-Q Ethernet module described here supports two communication protocols, TCP/IP and UDP/IP.

1.3.1 Communication model

"OSI reference model" is a famous communication mechanism model defined by ISO (International Organization for Standardization).

This model classifies the functions reguired for communication into 7 layers.

The bigger numbers correspond to the higher (morę logical) layers and the smaller numbers to the lower (morę physical) layers.

IP corresponds to the network layer, and both TCP and UDP to the transport layer. Ethernet corresponds to the data link layer and the physical layer.