Appendix 8 Tcp/Ip Communications, Udp/Ip Communications; Tcp/Ip Communications - Mitsubishi Electric MELSEC iQ-R Series User Manual

Appendix 8
This chapter describes the communication flow and procedure of TCP/IP communications and UDP/IP communications.

TCP/IP communications

This section describes TCP/IP communications.
Establishing a connection
With TCP/IP communications, a connection must be established between the communicating devices. If the server side
device has executed the Passive open processing and is in the standby state, the client side device makes an open request
(Active open processing) to the server. When a response is returned, the connection is established.
With TCP/IP communications, a connection is established during communication. Since data is exchanged while checking
that the data has correctly reached the communication destination, the data reliability can be ensured. Note that the line load
is larger than UDP/IP communications.
Ex.
When the CC-Link IE TSN Plus module is Passive open
Server
CC-Link IE TSN Plus module
Passive open
(Passive)
TCP/IP Communications, UDP/IP
Communications
Open request
Response
Connection

Appendix 8 TCP/IP Communications, UDP/IP Communications

Client
External device
Active open
(Active)
A
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