An introduction on how to connect nodes can be found in the tutorial How nodes are connected to each other.
This plugin contains the transport code for transporting data. The NY_NetworkPlugIn plugin, on the other hand, is placed in a layer above it. It organizes the transport of messages based on a transport layer. It also follows that the TCP protocol can be replaced by another protocol.
The TCP plugin is about the creation and operation of TCP servers and TCP clients. Both can be created by configuration or by messages. The deletion of servers and clients is only possible via messages.
The creation of servers and clients by configuration is shown in the tutorial How nodes are connected to each other.
The settings for the TCP servers and clients can be found here.
The records with which you can start servers and clients as well as the notifications of the TCP plugin can be found here.