Networking

A network is a set of nodes (devices) connected by communication links.

Node: Computer, printer, or any other device capable of sending and or receiving data generated by other nodes on the network. In computer networks we need at least two computing devices and other devices such as routers, switches and communication links to connect computers together. There are four main network criteria.

1. Performance

Performance is shown as transit time, response time, bandwidth (throughput) and latency.

Transit time — Transit time is the amount of time required for a message to travel from one device to another

Response time — The time required to receive a response to a request

Bandwidth — Amount of data that can be transmitted per time unit

Throughput is an actual measure of how much data is successfully transferred from source to destination, and bandwidth is a theoretical measure of how much data could be transferred from source to destination. Throughput and bandwidth are two different but it has similar concepts.

Latency — Latency is sometimes referred to as delay. The latency of a network is as close to zero as possible.

2. Reliability

Reliability is the measure of how often a network is useable. It is measure of the average time a component is expected to operate between failures. It can be hardware, data transmission and network operating system.

3. Security

Network security issues include protecting data from unauthorized access, protecting data from damage and development, and implementing policies and procedures for recovery from breaches and data losses.

4. Recovery

Recovery is the networks ability to return to a prescribed level of operation after a network failure. Recovery is based on having back — up files.

Network Classification

Network can be classified into different types. Based on geographical spread, networks can be classified into three categories.

Local Area Network(LAN)

Local Area Network is a group of computers connected in a small geographical area such as a building and office. LAN is used for connecting two or more computing devices through a communication medium such as twisted pair, coaxial cable, and fiber optics. It is less costly and has built with hardware such as hubs, network adapters and Ethernet cables.

Metropolitan Area Network(MAN)

MAN is the interconnection of local area networks in activity into a single network. The size of the Metropolitan area network is larger than LANs and smaller than WAN.

Wide Area Network(WAN)

Wide area network provides long distance transmission of data. The size of the WAN is larger than LAN and MAN. A WAN can cover country or a whole world. Internet is an example of WAN.