Which network device creates and sends the initial packet of a session?

The source device originates network communication by creating and transmitting the initial packet of a session - for example, the TCP SYN segment - and its address populates the source field in the IP and transport-layer headers throughout the exchange.

'Origination' is not a recognized standard networking term for a device role; the correct and universally accepted term for the session-initiating device is 'source'.

The destination device receives the initial packet from the source and responds; it does not create or transmit the session-opening packet.

'Network' describes the interconnected infrastructure that carries packets between devices and is not a device-role term used to describe session initiation.