The work of a network administrator is just that - long hours in front of computers. There is not much traveling involved. Minimal physical activity may be required when troubleshooting hardware. Sometimes it is necessary to come down to the specific station to investigate the problem. But mostly, the administrator communicates via phone or internet and offers support from behind his own desk.
Network administrators are typically enthusiastic about everything computer related and have a perfect understanding of what might go wrong. They are friendly people, though not necessarily charismatic leaders or great speakers. They give quick, cordial, and, most importantly, extremely efficient service.
Network administrators deal primarily with whole systems of corporate computers. They are hired to plan out in advance the company's computer security. They implement it and perform regular maintenance. Security involves firewall installation, cryptography, adding or deleting users, backup and recovery, etc.
Network administrators deal with systems. These systems have what is called "architecture." Some administrators, but not all, specialize in the structure of computer systems.
Network administrators run checks to detect and prevent bugs, breakdowns, viruses, hackers, etc. They are always up-to-date with the latest enhancements in the market and install upgrades whenever necessary.
Data encapsulation is the process of breaking down information into smaller manageable chunks before it is transmitted across the network. It is also in this process that the source and destination addresses are attached into the headers, along with parity checks.
Network Topology refers to the layout of a computer network. It shows how devices and cables are physically laid out, as well as how they connect to one another.
VPN means Virtual Private Network, a technology that allows a secure tunnel to be created across a network such as the Internet. For example, VPNs allow you to establish a secure dial-up connection to a remote server.
NAT is Network Address Translation. This is a protocol that provides a way for multiple computers on a common network to share single connection to the Internet.
The Network layer is responsible for data routing, packet switching and control of network congestion. Routers operate under this layer.