ABSTRACT
NA: Numerical Aperture. NADF: North American Directory Forum. nadir: The point which is diametrically opposite to the zenith and con-
stitutes the lowest point of all. nailed-up circuit: A circuit which is set up through a switching system to
provide a semipermanent connection between two points. NAK: Negative Acknowledgement. NAM: Numerical Assignment Module. name management: An aspect of configuration management, it allows the
user symbolically to name and refer to resources on the network. Several techniques exist for this, the most popular being white pages and yellow pages.
