Computer networks are generally classified according to their structure and the area they are localized in as:
1. Local area network (LAN)
A local area network is a network of computers joined together in a local area such as a small office, a home, or a building. The area covered by a LAN is usually restricted to a single location. The function of a LAN is to provide high-speed connectivity to all computers and network devices. The data transfer speed achieved in a LAN is significantly higher than its counter part, the wide area network (WAN).
1. Local area network (LAN)
A local area network is a network of computers joined together in a local area such as a small office, a home, or a building. The area covered by a LAN is usually restricted to a single location. The function of a LAN is to provide high-speed connectivity to all computers and network devices. The data transfer speed achieved in a LAN is significantly higher than its counter part, the wide area network (WAN).
However, one LAN can be connected to another LAN over any distance via telephone lines and radio waves. A system of LANs connected to this way is called a wide-area network(WAN).
Most LANs connect workstations and personal computers. Each node in a LAN has its own CPU with which it executes programs, but it is also able to access data and devices anywhere on the LAN.
The following characteristics differentiate one LAN from another:
Topology: The geometric arrangement of devices on the network. For example, devices can be arranged in a ring or in a straight line.
Protocols: The rules and encoding specifications for sending data. The protocol also determine whether the network uses peer-to-peer or client/server architecture.
Media: Devices can be connected by twisted-pair wire, coaxial cables, or fiber optic cables.
Most LANs connect workstations and personal computers. Each node in a LAN has its own CPU with which it executes programs, but it is also able to access data and devices anywhere on the LAN.
The following characteristics differentiate one LAN from another:
Topology: The geometric arrangement of devices on the network. For example, devices can be arranged in a ring or in a straight line.
Protocols: The rules and encoding specifications for sending data. The protocol also determine whether the network uses peer-to-peer or client/server architecture.
Media: Devices can be connected by twisted-pair wire, coaxial cables, or fiber optic cables.
LANs are capable of transmitting data at a very fast rates, much faster than data can be transmitted over a telephone line; but the distances are limited, and there is also a limit on the numbers of computer that can be attached to a single LAN.
The typical characteristics of LAN are:
*Confined to small areas (5 to 10 km)
*High speed
*Most inexpensive equipment
*Low error rates
*Data and hardware sharing between user owned by the user.
*Operates at speed ranging from 10Mbps to 100Mbps. Now a days 1000Mbps are available.
2. Wide area network (WAN)
A wide area network is a network that connects two or more local area networks. A WAN typically connects separate LANs at different geographic locations. A third party such as an Internet service provider (ISP) or a local telephone company is responsible for providing the required dedicated hardware and/or connectivity lines to implement a WAN. These hardware devices include modems or routers that are required to connect the local LANs to the service provider’s network.
A wide area network is a network that connects two or more local area networks. A WAN typically connects separate LANs at different geographic locations. A third party such as an Internet service provider (ISP) or a local telephone company is responsible for providing the required dedicated hardware and/or connectivity lines to implement a WAN. These hardware devices include modems or routers that are required to connect the local LANs to the service provider’s network.
The typical characteristics of a WAN are:
*A WAN can range from 100km to 1000km and the speed between cities can vary from 1.5 Mbps to 2.4 Gbps.
*WAN supports large number of computers and multiple host machines.
*Usually the speed is much slower than LAN speed.
*Highest possible error rate compared to LAN and MAN.
*A WAN can range from 100km to 1000km and the speed between cities can vary from 1.5 Mbps to 2.4 Gbps.
*WAN supports large number of computers and multiple host machines.
*Usually the speed is much slower than LAN speed.
*Highest possible error rate compared to LAN and MAN.
3. Personal area network (PAN)
Unlike the name suggests, a personal area network may or may not belong to a single person. The term PAN refers to a network of devices located in close proximity of each other. The devices may include such items as computers, PDAs, or mobile phones, that are connected using a wireless or a wired network. A mobile phone connected to a computer, or a few laptops connected to each other in an ad-hoc fashion are examples of personal area networks. Similarly, two or more computers sharing an Internet connection in a home network is another example of a PAN.
Unlike the name suggests, a personal area network may or may not belong to a single person. The term PAN refers to a network of devices located in close proximity of each other. The devices may include such items as computers, PDAs, or mobile phones, that are connected using a wireless or a wired network. A mobile phone connected to a computer, or a few laptops connected to each other in an ad-hoc fashion are examples of personal area networks. Similarly, two or more computers sharing an Internet connection in a home network is another example of a PAN.
4. Metropolitan area network (MAN)
A metropolitan area network is a large inter-network connecting local area networks in a campus or inside the boundaries of one city. The MANs are usually connected using high-speed fiber optic cables. Metropolitan Area Networks can further be connected to form wide area networks.
The typical characteristics of MAN are:
*Confined to a large area than a LAN and can range from 10km to a few 100km in length.
*Slower than a LAN but faster than a WAN.
*Operate at a speed of 1.5 to 150Mbps.
*Expensive equipment
*Moderate error rates.
A metropolitan area network is a large inter-network connecting local area networks in a campus or inside the boundaries of one city. The MANs are usually connected using high-speed fiber optic cables. Metropolitan Area Networks can further be connected to form wide area networks.
The typical characteristics of MAN are:
*Confined to a large area than a LAN and can range from 10km to a few 100km in length.
*Slower than a LAN but faster than a WAN.
*Operate at a speed of 1.5 to 150Mbps.
*Expensive equipment
*Moderate error rates.
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