Open system: An open system in networking is a system that allows any two devices on the network to communicate with each other regardless of the manufacturer or model of the devices. Open systems follow standards that allow for interoperability between different devices and vendors.

Closed system: A closed system is not connected to a network and so cannot be communicated with by other networks or devices outside of the closed system.

IP (internet protocol) address: The network address of the system across the network, which is also known as the Logical Address.

MAC address: The MAC address or physical address uniquely identifies each host. It is associated with the Network Interface Card (NIC).

Port: A port is a channel through which data is sent and received.

Nodes: Nodes is a term used to refer to any computing devices, such as computers, that send and receive network packets across the network.

Network packets: The data that is sent to and from the nodes in a network.

Routers: Routers are hardware devices that manage router packets. They determine which node the information came from and where to send it. A router has a routing protocol which defines how it communicates with other routers.

More info: computer information technology