With connections, polling is not necessary because there is only one terminal per line.

With point-to-point (P2P) connections, polling is not necessary because there is only one terminal per line.​ The term polling denotes the process in operating system in which the computer or controlling device waits for an external device to check for its readiness or state. 
So in a point-to--point connection, there is one controlling and one controlled device.

It is c commensalism