Examples of the computer network are LAN, MAN, WAN and internet. Internet is the largest computer network.
Ethernet is a large frame based computer network technology for the local area networks. The name Ethernet comes from physical concept of Ether which defines a number of wiring and signaling standards for the physical layer. Ethernet has been standardized as IEEE 802.3 and its star-topology twisted pair wiring became the most wide spread network type till present. Ethernet technology replaced the old networking technologies such as coaxial cable Ethernet, token ring, ARCNET and FDDI.
A simple computer network may be developed from two or more computers. Each computer will require a NIC card and a special cable known as a cross over cable. If the computers are more than two then a specialized networking device known as hub or switch will be required and all the computers in a network will be connected with the hub or switch. A simple network is useful for home networking. Additionally, a network between the two computers can be established by using a standard connection such as Rs-232 serial port on both computers connecting with each other by a special cross lined null modem cable.
Practical networks generally consist of more than two computers and require specialized devices along with the NIC cards and these devices can be hubs, modems, switches, routers and others.
Common Types of Networks:
Following is the list of the common computer networking types.
LAN (Local Area Network):
A network that is limited to a relatively small geographical area such as a room, building, school network, ship, aircraft or a small office. LANs are also known as single location networks. The large LANs may be divided into the smaller logical segments known as workgroups.
CAN (Campus Area Network):
A network that connects two or more small LANs and is limited to a specific geographical area, such as a school, college, university campus or a military base, is known as a CAN. A CAN is generally confined to an area that is smaller than a Metropolitan area network.
MAN (Metropolitan Area Network):
A network that connects two or more LANs or CANs within a geographical area in a town, city or a metropolitan area is known as a MAN. A number or communication devices are required to create a MAN such as routers, switches, hubs and modems etc.
WAN (Wide Area Networks):
A WAN is a data communication network type that covers a very large geographical area. WAN networks can be privately owned such as a multi national company network or publically own such as internet. WAN technology generally functions at the lower three layers of the OSI model. Internet is the best example of WAN. There are two main types of WAN centralized and distributed WAN. The centralized WAN consists of a central computer that is connected to the dumb terminal or other types of the communication devices, such as a bank and post office networks. The distributed WAN consists of two or more computers that are physically placed at different locations and may also include connections to dumb terminal and other connecting devices.
Two or more networks or connecting together using communication devices such as router. Any interconnection between private, commercial, public or government network may also be defined as internetwork. A specific internetwork consists of international interconnection of government, public and private networks.
An internetwork or a network that is limited to a single organization and uses TCP/IP protocol suite, HTTP, FTP and other protocols. Intranet can be categorized into LAN, MAN, CAN and WAN. Intranet is a company’s private network that is only accessible to the authorized users.
Extranet is a combination of intranet and some other trusted networks. For example a company’s customer may be provided access to the intranet, creating an intranet and while at the same time the customer may not be considered trusted with regards to the security of the company. An extranet can also be categorized into CAN, MAN and WAN and by definition extranet cannot be considered to consist of only a single LAN. An extranet must have at least one connection the extra network. Intranet and extranet may also have the connections to the internet. But only the authorized users can enter into the extranet internet plays a role only of a portal.
A virtual LAN commonly known as VLAN is a method of creating independent logical networks within a physically network. Many Vlans can consist in a physical network. Vans help in reducing the broadcast domain and aids in network administration by separating the logical segments of a LAN. VLANS behaves as if connected to the same wire even though they may actually be physically connected to the different segments of a LAN. VLANs can be configured with software rather than hardware. One main advantage of the VLAN is that when computers are physically moved from one location to another, they can stay on the same VLAN without the reconfiguration of the hardware and software.
TYPES OF TOPOLOGY
Ethernet and local talk networks use linear bus topology. In Linear Bus topology, each device is directly connected to the linear cable.
In the star topology each node such as computers, file server, workstations and peripheral devices are directly connected to the centralized device known as hub or switch. Data in the star topology passes through the hub or switch before it reaches to the destination. Hub or concentrators also act as repeaters for the data flow. Twisted pair cable, coaxial cable, and fiber optic cables can be used. Star wired topology appears to the same as star topology. The Token Ring protocol uses star-wired ring topology.
Tree topology is the combination of the linear bus and star topology. Linear Bus consists of the star configured workstations connected to the Linear Bus backbone cable.
Token Ring was developed by several manufactures and it is used for high traffic network loadings. Ethernet now has taken the popularity of the Token Rings.
Numerous types of the computer networking hardware is used develop a computer network such as Routers, hubs, workstations, NIC cards, servers, firewall, switches, bridges, modems, local talk connectors, UTP/STP cables and many other types of basic and advance communication hardware.