Types of Computer Networks

Types of Computer Networks:

LAN, MAN, WAN, VPN What Are the Important Types of Computer Networks

There are various types of computer networks available. We can categorize them according to their size as well as their purpose.

The size of a network should be expressed by the geographic area and number of computers, which are a part of their networks. It includes devices housed in a single room to millions of devices spread across the world.

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Some of the most popular network types are:

  • PAN
  • LAN
  • MAN
  • WAN

PAN (Personal Area Network)

PAN is a computer network formed around a person. It generally consists of a computer, mobile, or personal digital assistant. PAN can be used for establishing communication among these personal devices for connecting to a digital network and the internet.

Characteristics of PAN

  1. It is mostly personal devices network equipped within a limited area.
  2. Allows you to handle the interconnection of IT devices at the surrounding of a single user.
  3. PAN includes mobile devices, tablet, and laptop.
  4. It can be wirelessly connected to the internet called WPAN.
  5. Appliances use for PAN: cordless mice, keyboards, and Bluetooth systems.

Advantages of PAN

Here, are important pros/benefits of using PAN network:

  1. PAN networks are relatively secure and safe
  2. It offers only short-range solution up to ten meters
  3. Strictly restricted to a small area

Disadvantages of PAN

Here are important cons/ drawback of using PAN network:

  1. It may establish a bad connection to other networks at the same radio bands.
  2. Distance limits.

LAN ( Local Area Network )

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A Local Area Network (LAN) is a group of computer and peripheral devices which are connected in a limited area such as school, laboratory, home, and office building. It is a widely useful network for sharing resources like files, printers, games, and other application. The simplest type of LAN network is to connect computers and a printer in someone’s home or office. In general, LAN will be used as one type of transmission medium.

It is a network which consists of less than 5000 interconnected devices across several buildings.

Characteristics of LAN

Here are important characteristics of a LAN network:

  1. It is a private network, so an outside regulatory body never controls it.
  2. LAN operates at a relatively higher speed compared to other WAN systems.
  3. There are various kinds of media access control methods like token ring and ethernet.

Advantages of LAN

Here are pros/benefits of using LAN:

  1. Computer resources like hard-disks, DVD-ROM, and printers can share local area networks. This significantly reduces the cost of hardware purchases.
  2. You can use the same software over the network instead of purchasing the licensed software for each client in the network.
  3. Data of all network users can be stored on a single hard disk of the server computer.
  4. You can easily transfer data and messages over networked computers.
  5. It will be easy to manage data at only one place, which makes data more secure.
  6. Local Area Network offers the facility to share a single internet connection among all the LAN users.

Disadvantages of LAN

Here are the important cons/ drawbacks of LAN:

  1. LAN will indeed save cost because of shared computer resources, but the initial cost of installing Local Area Networks is quite high.
  2. The LAN admin can check personal data files of every LAN user, so it does not offer good privacy.
  3. Unauthorized users can access critical data of an organization in case LAN admin is not able to secure centralized data repository.
  4. Local Area Network requires a constant LAN administration as there are issues related to software setup and hardware failures

WAN ( Wide Area Network )

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WAN (Wide Area Network) is another important computer network that which is spread across a large geographical area. WAN network system could be a connection of a LAN which connects with other LAN’s using telephone lines and radio waves. It is mostly limited to an enterprise or an organization.

Characteristics of LAN

  • The software files will be shared among all the users; therefore, all can access to the latest files.
  • Any organization can form its global integrated network using WAN.

Advantages of WAN

Here are the benefits/ pros of using WAN:

  1. WAN helps you to cover a larger geographical area. Therefore business offices situated at longer distances can easily communicate.
  2. Contains devices like mobile phones, laptop, tablet, computers, gaming consoles, etc.
  3. WLAN connections work using radio transmitters and receivers built into client devices.

Disadvantage of WAN

Here are drawbacks/cons of using WAN:

  1. The initial setup cost of investment is very high.
  2. It is difficult to maintain the WAN network. You need skilled technicians and network administrators.
  3. There are more errors and issues because of the wide coverage and the use of different technologies.
  4. It requires more time to resolve issues because of the involvement of multiple wired and wireless technologies.
  5. Offers lower security compared to other types of networks.

MAN ( Metropolitan Area Network )

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A Metropolitan Area Network or MAN is consisting of a computer network across an entire city, college campus, or a small region. This type of network is large than a LAN, which is mostly limited to a single building or site. Depending upon the type of configuration, this type of network allows you to cover an area from several miles to tens of miles.

Characteristics of MAN

Here are important characteristics of the MAN network:

  1. It mostly covers towns and cities in a maximum 50 km range
  2. Mostly used medium is optical fibers, cables
  3. Data rates adequate for distributed computing applications.

Advantages of MAN

Here are pros/benefits of using MAN system:

  1. It offers fast communication using high-speed carriers, like fiber optic cables.
  2. It provides excellent support for an extensive size network and greater access to WANs.
  3. The dual bus in MAN network provides support to transmit data in both directions concurrently.
  4. A MAN network mostly includes some areas of a city or an entire city.

Disadvantages of MAN

Here are drawbacks/ cons of using the MAN network:

  1. You need more cable to establish MAN connection from one place to another.
  2. In MAN network it is tough to make the system secure from hackers

11 Types of Networks in Use Today

1. Personal Area Network (PAN)

The smallest and most basic type of network, a PAN is made up of a wireless modem, a computer or two, phones, printers, tablets, etc., and revolves around one person in one building. These types of networks are typically found in small offices or residences, and are managed by one person or organization from a single device.

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2. Local Area Network (LAN)

We’re confident that you’ve heard of these types of networks before – LANs are the most frequently discussed networks, one of the most common, one of the most original and one of the simplest types of networks.

LANs connect groups of computers and lowvoltage devices together across short distances (within a building or between a group of two or three buildings in close proximity to each other) to share information and resources. Enterprises typically manage and maintain LANs.

Using routers, LANs can connect to wide area networks (WANs, explained below) to rapidly and safely transfer data.

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3. Wireless Local Area Network (WLAN)

Functioning like a LAN, WLANs make use of wireless network technology, such as WiFi. Typically seen in the same types of applications as LANs, these types of networks don’t require that devices rely on physical cables to connect to the network.

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4. Campus Area Network (CAN)

Larger than LANs, but smaller than metropolitan area networks (MANs, explained below), these types of networks are typically seen in universities, large K-12 school districts or small businesses. They can be spread across several buildings that are fairly close to each other so users can share resources.

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5. Metropolitan Area Network (MAN)
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These types of networks are larger than LANs but smaller than WANs – and incorporate elements from both types of networks. MANs span an entire geographic area (typically a town or city, but sometimes a campus). Ownership and maintenance is handled by either a single person or company (a local council, a large company, etc.).

6. Wide Area Network (WAN)
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Slightly more complex than a LAN, a WAN connects computers together across longer physical distances. This allows computers and low-voltage devices to be remotely connected to each other over one large network to communicate even when they’re miles apart.

The Internet is the most basic example of a WAN, connecting all computers together around the world. Because of a WAN’s vast reach, it is typically owned and maintained by multiple administrators or the public.

7. Storage-Area Network (SAN)

As a dedicated high-speed network that connects shared pools of storage devices to several servers, these types of networks don’t rely on a LAN or WAN. Instead, they move storage resources away from the network and place them into their own highperformance network.

SANs can be accessed in the same fashion as a drive attached to a server. Types of storage-area networks include converged, virtual and unified SANs.

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8. System-Area Network (also known as SAN)

This term is fairly new within the past two decades. It is used to explain a relatively local network that is designed to provide high-speed connection in server-to-server applications (cluster environments), storage area networks (called “SANs” as well) and processor-to-processor applications. The computers connected on a SAN operate as a single system at very high speeds.

9. Passive Optical Local Area Network (POLAN)

As an alternative to traditional switch-based Ethernet LANs, POLAN technology can be integrated into structured cabling to overcome concerns about supporting traditional Ethernet protocols and network applications such as PoE (Power over Ethernet).

A point-to-multipoint LAN architecture, POLAN uses optical splitters to split an optical signal from one strand of singlemode optical fiber into multiple signals to serve users and devices.

10. Enterprise Private Network (EPN)

These types of networks are built and owned by businesses that want to securely connect its various locations to share computer resources.

11. Virtual Private Network (VPN)

By extending a private network across the Internet, a VPN lets its users send and receive data as if their devices were connected to the private network – even if they’re not. Through a virtual point-to-point connection, users can access a private network remotely.

Difference between Client-Server and Peer-to-Peer Network

Client-Server Network:

This model are broadly used network model. In Client-Server Network, Clients and server are differentiated, Specific server and clients are present. In Client-Server Network, Centralized server is used to store the data because its management is centralized.In Client-Server Network, Server respond the services which is request by Client.

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Peer-to-Peer Network:

This model does not differentiate the clients and the servers, In this each and every node is itself client and server. In Peer-to-Peer Network, Each and every node can do both request and respond for the services.

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Difference between Client-Server and Peer-to-Peer Network:

CLIENT-SERVER NETWORKPEER-TO-PEER NETWORK
In Client-Server Network, Clients and server are differentiated, Specific server and clients are present.In Peer-to-Peer Network, Clients and server are not differentiated.
In Client-Server Network, Centralized server is used to store 3. the data.While in Peer-to-Peer Network, Each peer has its own data.
In Client-Server Network, Server respond the services which is request 4.           by Client.While in Peer-to-Peer Network, Each and every node can do both request and respond for the services.
Client-Server Network are costlier 5.      than Peer-to-Peer Network.While Peer-to-Peer Network are less costlier than Client-Server Network.
Client-Server Network focuses on information sharing. While Peer-to-Peer Network focuses on connectivity.
  While Peer-to-Peer Network is Client-Server Network is used for both small and large networks. generally suited for small networks with fewer than 10 computers.
Client-Server Network are more 6.      stable than Peer-to-Peer Network.While Peer-to-Peer Network are less stable if number of peer is increase.

P2P(Peer To Peer) File Sharing

Introduction

In Computer Networking, P2P is a file sharing technology, allowing the users to access mainly the multimedia files like videos, music, e-books, games etc. The individual users in this network are referred to as peers. The peers request for the files from other peers by establishing TCP or UDP connections.

How P2P works(Overview)

A peer-to-peer network allows computer hardware and software to communicate without the need for a server. Unlike client-server architecture, there is no central server for processing requests in a P2P architecture. The peers directly interact with one another without the requirement of a central server.

Now, when one peer makes a request, it is possible that multiple peers have the copy of that requested object. Now the problem is how to get the IP addresses of all those peers. This is decided by the underlying architecture supported by the P2P systems. By means of one of these methods, the client peer can get to know about all the peers which have the requested object/file and the file transfer takes place directly between these two peers.

Three such Architectures exist:

  1. Centralized Directory
  2. Query Flooding
  3. Exploiting Heterogeneity

1. Centralized Directory

  • It is somewhat similar to client server architecture in the sense that it maintains a huge central server to provide directory service.
  • All the peers inform this central server of their IP address and the files they are making available for sharing.
  • The server queries the peers at regular intervals to make sure if the peers are still connected or not.
  • So basically this server maintains a huge database regarding which file is present at which IP addresses.

Working

  • Now whenever a requesting peer comes in, it sends its query to the server.
  • Since the server has all the information of its peers, so it returns the IP addresses of all the peers having the requested file to the peer.
  • Now the file transfer takes place between these two peers.

The first system which made use of this method was Napster, for the purpose of Mp3 distribution.

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The major problem with such an architecture is that there is a single point of failure. If the server crashes, the whole P2P network crashes. Also, since all of the processing is to be done by a single server so a huge amount of database has to be maintained and regularly updated.

2. Query Flooding

  • Unlike the centralized approach, this method makes use of distributed systems.
  • In this, the peers are supposed to be connected into an overlay network. It means if a connection/path exists from one peer to other, it is a part of this overlay network.
  • In this overlay network, peers are called as nodes and the connection between peers is called an edge between the nodes, thus resulting in a graph-like structure.

Working

  • Now when one peer requests for some file, this request is sent to all its neighboring nodes i.e. to all nodes which are connected to this node. If those nodes don’t have the required file, they pass on the query to their neighbors and so on. This is called as query flooding.
  • When the peer with requested file is found (referred to as query hit), the query flooding stops and it sends back the file name and file size to the client, thus following the reverse path.
  • If there are multiple query hits, the client selects from one of these peers.

Gnutella was the first decentralized peer to peer network.

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This method also has some disadvantages like, the query has to be sent to all the neighboring peers unless a match is found. This increases traffic in the network.

3. Exploiting heterogeneity

  • This P2P architecture makes use of both the above discussed systems.
  • It resembles a distributed system like Gnutella because there is no central server for query processing.
  • But unlike Gnutella, it does not treat all its peers equally. The peers with higher bandwidth and network connectivity are at a higher priority and are called as group leaders/super nodes. The rest of the peers are assigned to these super nodes.
  • These super nodes are interconnected and the peers under these super nodes inform their respective leaders about their connectivity, IP address and the files available for sharing.

KaZaA technology is such an example which makes use of Napster and Gnutella both. Thus, the individual group leaders along with their child peers form a Napster-like structure. These group leaders then interconnect among themselves to resemble a Gnutella-like structure.

Working

  1. This structure can process the queries in two ways.
  2. The first one is that the super nodes could contact other super nodes and merge their databases with its own database. Thus, this super node now has information of a large number of peers.
  3. Another approach is that when a query comes in, it is forwarded to the neighboring super nodes until a match is found, just like in Gnutella. Thus query flooding exists but with limited scope as each super node has many child peers. Hence, such a system exploits the heterogeneity of the peers by designating some of them as group leaders/super nodes and others as their child peers.
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What Are Hybrid Networks?

A hybrid network is any computer network that uses more than one type of connecting technology or topology.

For example, a home network that uses both Wi-Fi and Ethernet cables to connect computers is a hybrid. In the early years of computer networking, hybrid networks often consisted of Token Ring or Star technologies, however these were quickly antiquated by Ethernet. While textbooks often refer to these types of hybrids, they are basically extinct in 2014.

Home Network Hybrids

Although Ethernet and Wi-Fi usually use the same router in a home network, this doesn’t mean that the technology behind them is identical. Both have different specifications developed by the IEEE Standards Association.

Ethernet cable networks use the 802.3 standards, while Wi-Fi networks use 802.11. These standards have different rules about how data is transferred. A home WiFi Ethernet router is a hybrid device that brings these two different technologies together.

Without such a hybrid device, there would be no way to connect an Ethernet-based desktop to a Wi-Fi-based tablet on the same network.

Advantages of Hybrids

The two main advantages of a hybrid network are cost-savings and accessibility. If you have an Ethernet network at home and buy a tablet, rather than replacing all of your Ethernet components with Wi-Fi, you can simply add a Wi-Fi router to your existing network.

The same is true for business networks, but on a larger scale. Few businesses have the budget to replace an entire network all at once. Hybrids allow a business to bring in new networking technologies, while phasing out old technologies over the course of several years.

Disadvantages of Hybrids

The main disadvantage of hybrids are security and support costs. Each network technology introduces new security concerns. Having a router with a good firewall becomes meaningless, for example, if you add a Wi-Fi access point that hasn’t been encrypted with a strong password.

In business networks, supporting different types of network technologies can become expensive, since they usually need someone with expertise in each technology. Business hybrid networks are always the result of balancing the need for a fast, accessible network with the need for data security.

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