For a specific purpose if things are connected together, are referred as a NETWORK. A network can be of many types, like a telephone network, television network, computer network or even a people network.
Similarly, a COMPUTER NETWORK is also a kind of setup, where it connects two or more devices to share a range of services and information in the form of e-mails and messages, databases, documents, web-sites, audios and videoes, Telephone calls and video conferences etc among them.
A PROTOCOL is nothing but set of defined rules, which has to be followed by every connected devices across a network to communicate and share information among them. To facilitates End to End communication, a number of protocols worked together to form a Protocol Suites or Stacks.
Some basic Protocols are:
The Network reference models were developed to allow products from different manufacturers to interoperate on a network. A network reference model serves as a blueprint, detailing standards for how protocol communication should occur.
The most widely recognized reference models are, the Open Systems Interconnect ( OSI ) Model and Department of Defense ( DoD, also known as TCP/IP ) model.
Network Types are often categorized by their size and functionality. According to the size, the network can be commonly categorized into Three types.
- LANs (Local Area Networks)
- MANs (Metropolitan Area Networks)
- WANs (Wide Area Networks)
An Internetwork is a general term describing multiple networks connected together. The Internet is the largest and most well-known internetwork.
- SAN (Storage Area Network): A SAN provides systems with high-speed, lossless access to high-capacity storage devices.
- VPN (Virtual Private Network): A VPN allows for information to be securely sent across a public or unsecure network, such as the Internet. Common uses of a VPN are to connect branch offices or remote users to a main office.
Some networks are categorized by their function, as opposed to their size. For example:
In a network, any connected device is called as host. A host can serve as following ways:
- A host can acts as a Client, when he is requesting information.
- A host can acts as a Server, when he provides information.
- A host can also request and provide information, is called Peer.
Refer for Set 1: Basics of Computer Networking.