Computer Networks 03: Types of Computer Network.

Distinguishing one network type from another can be challenging and sometimes perplexing. Criteria such as size, geographical scope, and ownership are utilized to make these distinctions. Some of the most popular computer network types are:

• LAN (Local Area Network)
• MAN (Metropolitan Area Network)
• WAN (Wide Area Network)

Local Area Network 

A local area network (LAN) is usually privately owned and connects some hosts in a single office, building, or campus.  A LAN interconnects hosts. Each host in a LAN has an identifier, an address, that uniquely defines the host in the LAN. A packet sent by a host to another host carries both the source host’s and the destination host’s addresses. Depending on the needs of an organization, a LAN can be as simple as two PCs and a printer in someone’s home office, or it can extend throughout a company and include audio and video devices.

In the past, all hosts in a network were connected through a common cable, which meant that a packet sent from one host to another was received by all hosts. The intended recipient kept the packet; the others dropped the packet.

Today, most LANs use a smart connecting switch, which is able to recognize the destination address of the packet and guide the packet to its destination without sending it to all other hosts. The switch alleviates the traffic in the LAN and allows more than one pair to communicate with each other at the same time if there is no common source and destination among them.

There are two types of LAN:

• Wired LAN– In this type of LAN, wired cables such as twisted pair or coaxial cables are used for the connection and transmission of data.
• Wireless LAN– In this type of LAN, devices are connected by wireless cables such as radio, and light waves.

Characteristics of LAN network

• LAN is owned by the private owner.
• LAN can be used to connect printers, personal computers, etc.
• LAN Networks can be designed very easily.
• Troubleshooting of LAN networks is easy.
• The data transfer rate of the LAN network is approximately 10 Gbits/s.
• It is limited to the local area.
• A LAN typically operates at higher speeds compared to a WAN.

Advantages

• A LAN enables the sharing of computer peripherals such as printers and scanners, potentially reducing the expenses associated with purchasing costly hardware.
• A LAN allows the sharing of a single internet connection among devices connected to the network.
• A LAN offers robust security and the ability to tolerate faults effectively.
• It facilitates the transfer of data between individuals and devices at a high rate of transmission.

Disadvantages

• LAN can lower expenses by enabling the sharing of computer hardware, although the initial setup cost for a LAN can be quite substantial.
• The configuration and installation of a LAN network require technical and skilled manpower.
• The operation speed of the network can sometimes decrease due to the sharing of computer resources among multiple devices.

Metropolitan Area Network

A Metropolitan Area Network (MAN) is a type of computer network that spans a city, campus, or organizational territory, making it larger than a Local Area Network (LAN) but smaller than a Wide Area Network (WAN). It connects multiple LANs using high-speed backbone technologies like fiber optics, facilitating communication with moderate speeds and propagation delays. MANs are less fault-tolerant and more prone to congestion compared to LANs and WANs. MANs can use various transmission devices, such as modems and cables, with examples including high-speed DSL and cable company networks.

Characteristics of MAN network 

• A MAN is generally owned by a user group or a provider who provides service to users, as opposed to a single organization, as is the case in LANs.
• Main purpose is to connect LANs with WANs and the Internet.
• Systems for local video surveillance.
• CAD / CAM transmission.
• They provide coverage of 10 to 50 km, suitable for connecting offices, factories, or headquarters within a city.
• Data rates of MAN are moderate to high.

Advantages of MAN

• It enables high speed communication through high-speed mediums such as fiber optic cables.
• In metropolitan areas, deployment of VoIP services (Voice over Internet Protocol) eliminates the “obsolete” lines of analog telephony or ISDN.
• Provides connectivity over a larger geographical area than LAN.
• The dual bus architecture in a MAN enables simultaneous data transmission in both directions.
• Typically encompasses several areas within a city or can cover the entire city itself.

Disadvantages of MAN

• More cable is required to establish a MAN connection between two locations.
• Securing a MAN network poses significant challenges.
• May have limited fault tolerance and security compared to LANs.

Wide Area Network 

A LAN is normally limited in size, spanning an office, a building, or a campus; a WAN has a wider geographical span, spanning a town, a state, a country, or even the world. A WAN interconnects connecting devices such as switches, routers, or modems. A WAN is normally created and run by communication companies and leased by an organization that uses it. Two distinct examples of WANs today: point-to-point WANs and switched WANs.

Point-to-Point WAN: A point-to-point WAN is a network that connects two communicating devices through a transmission media (cable or air).

Switched WAN: A switched WAN is a network with more than two ends. A switched WAN, as we will see shortly, is used in the backbone of global communication today. We can say that a switched WAN is a combination of several point-to-point WANs that are connected by switches.

Characteristics of WAN network

• The size of the WAN network is larger than the LAN and MAN network. WAN is used to cover a large geographical area, like a country. 
• WANs can be utilized to establish connections both within and across the globe.
• Any office or organization can utilize a WAN to establish a globally integrated network.

Advantages of WAN

• WLAN connections operate through radio transmitters and receivers integrated into client devices.
• A WAN (Wide Area Network) is utilized to span a large geographical area, such as a country.
• WAN can be utilized to establish connections both within and across the globe.
• Offices located far apart can communicate effectively using a Wide Area Network (WAN).
• Enables the connection of devices such as mobile phones, laptops, tablets, etc.

Disadvantages of WAN

• The initial setup and configuration costs of investment are very high.
• It requires skilled technicians and network administrators.
• The broad scope and diverse technologies in use lead to an increase in errors and issues.
• Resolving issues takes longer due to the integration of various wired and wireless technologies.
• Provides lower security compared to other computer network types.

Differences between LAN, MAN, and WAN

Basis	LAN	MAN	WAN
Full-Form	LAN stands for local area network.	MAN stands for metropolitan area network.	WAN stands for wide area network.
Geographic Span	Operates in small areas such as the same building or campus.	Operates in large areas such as a city.	Operates in larger areas such as countries or continents.
Ownership	LAN’s ownership is private.	MAN’s ownership can be private or public.	While WAN also might not be owned by one organization.
Transmission Speed	The transmission speed of a LAN is high.	While the transmission speed of a MAN is average.	Whereas the transmission speed of a WAN is low.
Propagation delay	The propagation delay is short in a LAN.	There is a moderate propagation delay in a MAN.	Whereas, there is a long propagation delay in a WAN.
Congestion	There is less congestion in LAN.	While there is more congestion in MAN.	Whereas there is more congestion than MAN in WAN.
Design & Maintenance	LAN’s design and maintenance are easy.	While MAN’s design and maintenance are more difficult than LAN.	Whereas WAN’s design and maintenance are also more difficult than LAN as well as MAN.
Fault tolerance	There is more fault tolerance in LAN.	While there is less fault tolerance.	In WAN, there is also less fault tolerance.

Today, it is quite rare to find a LAN or a WAN operating independently; they are typically interconnected. The connection of two or more networks forms an internetwork, commonly known as the internet.