Definitions

Subnet Mask

The subnet mask indicated which parts of the IP address belong to the network and which parts belong to the host.

Class C IP

Class C IP address are given to small organizations that do not have a lot of hosts:

DHCP

Make a reservation on the DHCP to get a static IP address.  Routers have the DHCP service built in to them.

NAT

NAT translates the private Ip to the Public IP