refer to the attached document
(Eric)A connection in terms of connection-oriented routing requires two or more devices to establish synchronous communications. This entails the sender ensuring that the receiver is online, listening, and ready to receive. After that is established, data can be transmitted and the connection will be terminated. TCP is connection-oriented and requires a handshake to take place before data can be transmitted. This makes it more secure since you can verify the identity of the device that will be receiving the data packets.
Connectionless, on the other hand, means that the sender will transmit data blindly and won’t even know if a device is receiving the data. When I think of connectionless routing, the example that comes to mind is a radio station tower. It broadcasts a signal over a wide area that people can tune in to if they have the right equipment, but it doesn’t know or care if anyone is listening. Sending data without verifying the receiver can be a security issue, as you cannot make sure that it gets to the intended destination. UDP is inherently connectionless and still sees use in areas such as VoIP and video streaming due to the lack of overhead required with TCP.