Network Concepts and Classification

A network is a series of  points or nodes interconnected by communication lines. The nodes may be devices dedicated to single function such as computer used for client application or router used for connecting networks. The whole purpose of any network is to enable two endpoints, networks, servers, routers and so on to communicate with each other and transfer data.

Networking

Networks are typically classified by the amount of geographical coverage. There are 4 primary types: LAN ( Local Area Network ), MAN ( Metropolitan Area Network ), WAN ( Wide Area Network ) and CAN ( Campus Area Network ).

LAN ( Local Area Network )

A LAN is a data communication network which connects many computer or workstations ( computer and printer terminal ) and enables exchange among them over same network medium. LANs are usually confined to a geographically area such as home, school, computer laboratory, office building. or college campus. The distance between two end points connected on the same channel is usually upto 2 to 5 kms.

 

Characteristics of LAN:

• All the devices in a network share the transmission media
• Area covered is small
• Every device in a network can communicate with any other device in a network
• Usually cost of setting a network is low

WAN ( Wide Area Network )

Wide Are Networking connects multiple LANs that are geographically separate. This can be accomplished by connecting different LANs using services like dedicated leased line, dial-up phone, satellite links and data packet carrier services. WAN is high speed, long distance communication technology. The computer connected to WAN are connected to telephone lines or satellite. The main purpose of WAN is to provide reliable, fast and safe communication between two or more places.

The main difference between LAN and WAN is that, the LAN is under complete control of the owner , whereas WAN require another authority like Telephone Company. Usually LANs have a lower error rate than WANs.

MAN ( Metropolitan Area Network )

The Metropolitan Area Network ( MAN ) is larger computer network covering an area size of city, campus or building. Two main features which differentiate MAN from LAN or WAN are:

1. The size is between LAN and WAN. A MAN typically covers an area of between 5 to 50km diameter.
2. A MAN often acts as a high speed network to allow sharing of resources. It is also used to provide a shared connections to other networks using a link to WAN.

CAN ( Campus Area Network )

A Campus Network or Campus Area Network or Corporate Area Network or CAN is a computer network made up of  interconnection of local area networks (LANs) within a limited geographical area. The Networking equipments (switches, routers) and transmission media (optical fiber, copper plant, Cat5 cabling etc) are almost entirely owned

In the case of a university, the network is likely to link a variety of campus buildings including; academic departments, the university library and student residence halls.

PAN ( Personal Area Network )

A PAN is a computer network organized around an individual person. It is typically involve a mobile computer, a cell phone and a hand-held computing. You can use these networks to transfer files including email and calendar appointments, digital photos and music etc.

Personal area networks can be constructed with cables or wirelessly. USB and FireWire technologies often link together a wired PAN while wireless PANs typically use Bluetooth or sometimes infrared connections. Bluetooth PANs are also called piconets.

Personal area networks generally cover a range of less than 10 meters (about 30 feet).

SAN ( Storage Area Network )

A SAN is a storage device such as disk arrays, tape libraries, and optical jukeboxes accessible to the servers, so the devices appear as locally attached to the operating system. A SAN typically has its own network of storage devices that are generally not accessible through the regular network by regular devices. The cost and complexity of SANs dropped in the late 2000s, allowing wider adoption across both enterprise and small to medium sized business environments.

A SAN alone does not provide the "file" abstraction, only block-level operations. However, file systems built on top of SANs do provide this abstraction, and are known as SAN filesystems or shared disk file systems.

Relationaship between LAN, MAN and WAN