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Archive for July, 2012

Basic Concepts of Computer Network

Posted by Darwis Suryantoro on July 4, 2012

Okkay Students, Let’s start our study now. In this section, we will discuss about Computer Networking. This is a “very fundamental” study before we learn more about Network Security.

First of all, you have to know about the definition of Computer Network. What is Computer Network? Computer Network is a collection (and “connection”) between two or more computer systems through communication media that allows them to make a data communication and resource sharing. Data or piece of information, hardware (e.g. printer, CD-ROM, harddisk), and other communication devices can be categorized as resource sharing.

The network can be connected by various communication media, such as: cable, radio, and satellite. The advantages of computer network:

  • SPEED. Network Computer will increase a pace of work in the organizations or companies. It easily users for data transfer between computers and other devices.
  • COST. We can reduce cost of hardware because it should be shared with another computers.
  • SECURITY. Computer Network gives access rights to users that using the systems. They will not access some information or data from another department in the organization or company they work for.
  • CENTRALIZED SOFTWARE MANAGEMENT.  It means, all programs (which be used in the network) must be centralized. This method can can reduce work time and power for installation into each computer.
  • RESOURCE SHARING. It could solve limitation not only hardware (e.g. printer, phone, CD-ROM, harddisk) but also data.
  • FLEXIBLE ACCESS. We can access Internet Banking using internet service all over the world.

Based on the architecture, network can be divided into three kinds, those are:

  • Host Terminal
  • Client Server
  • Peer to Peer

Every Computer Network is developed into different shape and measures. It depends on condition and needs. Nowadays, design of network computers are growing day by day. We may call this situation as network terminology. At first, LAN and WAN were originally designed for Networks. But now, they are growing rapidly.

Currently, there are so many area network, such as:

  • Personal Area Network (PAN)
  • Local Area Network (LAN)
  • Metropolitan Area Network (MAN)
  • Wide Area Network (WAN)
  • Storage Area Network (SAN)
  • System Area Network
  • Small Area Network
  • Desk Area Network
  • Controller Area Network
  • Cluster Area Network (CAN)
  • and others

Local Area Network (LAN) is a number of computers or communication devices in a small area (e.g. office) using certain communication media (e.g. cable, wireless, etc).


Local Area Network

LAN is designed for needs and condition like/ for:

  • It operates in the small geographic (or restricted) area.
  • To give an access to the user via communication media with higher bandwidth consumption than WAN.
  • To provide full-time connectivity for local services.
  • To do the best connection between devices in local area.
  • To provide a private network control under local Network Administrator.

Metropolitan Area Network (MAN) is a network which has wider operation area than LAN but smaller than WAN. The scope of MAN can be in the whole city, intercity, or inter-provincial.


Metropolitan Area Network


Wide Area Network (WAN) is a communication between LANs. Each LAN is separated with a geographic distance. For example, a relationship between central office and branch offices in country area or even overseas.

WAN technologies:

  • Modem
  • ISDN (Integrated Digital Subscriber Line)
  • DSL (Digital Subscriber Line)
  • Frame Relay
  • ATM (Asynchronous Transfer Mode)
  • SONET (Synchronous Optical Network)
Wide Area Network

Wide Area Network

WAN is designed for the condition like:

  • Wide geographic operation area
  • Access permission via serial interface with medium speed
  • Providing part/ full-time connectivity
  • Connecting devices which separated by a long distance

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