What is Network administration

Network administration is a modern day profession that
is directly responsible for the maintenance of Organizational
computer networks. Network administrator is responsible
for installing, maintaining, testing, monitoring oranizational
computer networks.

What is Add or Drop Multiplexing

First, I'll be discussing about some of the basic term in Networking.
Add/Drop Multiplexing is a common term in Networking, it
refers to A multiplexing function offered in connection with SONET
that helps lower level signals to be added or dropped from a speedy
optical carrier in a wire center. The connection to the add/drop multiplexer
is via a channel to a central port at a appropriate speed.