Computers Network

Computers  Network

        A computer network or data network is a telecommunications network that allows computers to exchange data. In computer networks, networked computing devices pass data to each other along data connections. The connections (network links) between nodes are established using either cable media or wireless media. The best-known computer network is the Internet.
       Network computer devices that originate, route and terminate the data are called network nodes. Nodes can include hosts such as personal computers, phones, servers as well as networking hardware. Two such devices are said to be networked together when one device is able to exchange information with the other device, whether or not they have a direct connection to each other.

The computer network have  4  types.

      1. local area  network (LAN)

       (LAN) is a computer network that interconnects computers within a limited area such as a home, school, computer laboratory, or office building, using network media. The defining characteristics of (LAN), in contrast to wide area networks (WAN), include their smaller geographic area, and non-inclusion of leased telecommunication lines.

    2.wide area network (WAN)

      is a network that covers a broad area (i.e., any telecommunications network that links across metropolitan, regional, national or international boundaries) using leased telecommunication lines. Business and government entities utilize WANs to relay data among employees, clients, buyers, and suppliers from various geographical locations. In essence, this mode of telecommunication allows a business to effectively carry out its daily function regardless of location. The Internet can be considered a WAN as well, and is used by businesses, governments, organizations, and individuals for almost any purpose imaginable.

3.metropolitan area network (MAN) 

           is a computer network larger than a local area network, covering an area of a few city blocks to the area of an entire city, possibly also including the surrounding areas.
           MAN is optimized for a larger geographical area than a LAN, ranging from several blocks of buildings to entire cities. MAN can also depend on communications channels of moderate-to-high data rates.  MAN might be owned and operated by a single organization, but it usually will be used by many individuals and organizations. MAN might also be owned and operated as public utilities. They will often provide means for inter networking of local networks.

   4.personal area network (PAN)

    is a computer network used for data transmission among devices such as computers, telephones and personal digital assistants. PANs can be used for communication among the personal devices themselves (intrapersonal communication), or for connecting to a higher level network and the Internet (an uplink).

    A wireless personal area network (WPAN) is a PAN carried over wireless network technologies such as:

•     IrDA

• Wireless USB   

• Bluetooth

• Z-Wave

• ZigBee

Data and picture from 

  - http://en.wikipedia.org/

  - http://www.techopedia.com/