NCP or Network Control Protocol:
A series of protocols for establishing and configuring different network layer protocols.
 

Network identifier:
Divided into five classes A to E. It is assigned by the Internet Numbering Authorities.
 

Network interface:
Boundary between a carrier network and a privately-owned installation.
 

Network Layer:
It is concerned with the physical transmission of the data from computer to computer. There is one further level of software to be considered, the network level. It routes the packages across a particular network.
 

Network Manager:
Person responsible for the operation, maintenance, and management of a network.
 

NIC France:
Organization providing information, assistance and services to network users.

Node:
Endpoint of a network connection or a junction common to two or more lines in a network.
 

NSF or National Science Foundation:
U.S. government agency that funds scientific research in the United States.
 

NSFnet or National Science Foundation Network:
Large network that was controlled by the NSF and provided networking services in support of education and research in the United States, from 1986 to 1995.
 

NTP or Network Time Protocol:
Protocol, defined in STD 12 and RFC 1119,  that assures accurate local timekeeping with reference to radio and atomic clocks located on the Internet. It is capable of synchronizing distributed clocks within milliseconds over long time periods.