Computers and networking go hand-in-hand, with their relationship going back to almost 70 years. To say that computers will be of little worth without networking would not be an understatement. After all, the several types of computer networks we have today have been empowering industries and households for decades.
Computer networks come in all shapes and sizes. Some are limited to a few meters, while others stretch out to outer space. And they all are integral to our lives, which is why it is only natural that we know about them in detail. This blog discusses the definition of computer networks, their types and their applications.
This blog discusses the definition of computer networks, their types and their applications. So, if you are a technology geek, a computer science student, a programmer or someone genuinely/casually interested in learning about computer networks, be sure to stay tuned till the end.
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Defining a Computer Network
A computer network, in simple terms, refers to the interconnection between two or more computers using which they share information and resources (data) among themselves. This interconnection can be wired or wireless depending upon the scale and the requirements of the connecting computers.
The internet, humanity’s greatest invention since the wheel, is a prime example of a computer network. It connects billions of devices – personal computers, smartphones, smart appliances, etc. – to each other and allows them to exchange data regardless of the distance between them.
Computer networks are composed of three primary elements: nodes, the communication medium and the network protocols. Let us look at these elements in more detail.
Nodes
As stated earlier, a computer network consists of interconnected computers. A node or a network node is a computer that is attached to a computer network and responsible for transmitting or accepting information over it. All network-enabled electronic devices connected to a network identify as nodes.
A network node can either function as a starting point/endpoint in a network or be used for data redistribution over it. Thus, a node can be your printer, personal computer, modem, wifi router, smartphone and any other such device.
Communication Medium
A communication medium in a computer network is a channel over which all the network nodes exchange data. This channel can consist of physical entities such as copper cables and fibre-optic cables or radio waves (wifi is a typical example).
Network Protocols
Merriam Webster defines a protocol as a set of rules and regulations that a system must follow for its proper functioning.
Thus, a network protocol is a set of rules that governs how a node should behave while connected to a computer network.
Network protocols allow devices with entirely different configurations to exchange data seamlessly over a network. They also command when and how a node will share data so as to not cause any network disruptions.
Hence, network protocols are pivotal to the optimal functioning of any computer network.
Different Types of Computer Networks
So far, we have discussed what a computer network is and also shed some light upon its core components. Now, it is time to address the elephant in the room: what are the different types of computer networks.
Based on their scale of connectivity, computer networks are classified into the following four categories:
PAN
Description
The first network type on this list is the PAN or Personal Area Network. A Personal Area Network refers to a computer network existing in the vicinity of an individual.
Thus, if you recently paired your smartphone to a Bluetooth speaker or printed a document using a wireless printer, you initialised a personal area network.
A PAN can be wired (USB) or wireless (wifi, Bluetooth and NFC) and usually has a range of up to ten metres or thirty-three feet.
History
The concept of PANs was first introduced to the world by Thomas Guthrie Zimmerman, a researcher at the MIT media lab.
He saw the viability of a network centred around a human body due to the rapidly decreasing size and power requirements of electronic devices.
Consequently, he put out a research paper on it. The paper explains the idea of an exclusively wireless network near a human body that enables devices to communicate using electric fields.
Purpose
People generally use PANs to interconnect devices such as smartwatches, Bluetooth headphones, smartphones, Bluetooth Mice and Keyboards within their personal space.
However, one can also employ a PAN to connect a host of personal devices to a common device. This device can further latch on to a broader network such as the web and allow the devices connected to it to access this network.
Pros
- Highly Portable
- Doesn’t require additional space to set up
- Safer than its wider counterparts due to the absence of third party unauthorised devices
- Better network stability (given the devices are within the prescribed network range)
- Pocket-friendly
Cons
- One of the biggest cons of PANs is their short signal range
- Data transmission rates are quite slow compared to other networks
- Wireless PANs can interfere with radio signals causing interruptions in data transfer
LAN
Description
A Local Area Network, abbreviated as LAN, is a type of computer network that connects devices within a limited geographical range. This range is wider than that of a PAN and can go from a few hundred to a few thousand meters.
LANs typically use either Ethernet (coaxial cables) or Wifi to establish a localised connection or connect to the internet.
History
The origins of Local Area Networks date back to the 1960s. It was a time when governmental institutions fancied a need for interconnecting computers within their premises.
As the demand for connecting computers grew, researchers devised many LAN concepts such as the Cambridge Ring and the ARCNET in the 1970s. However, the development of the Ethernet at XEROX PARC (1973-74) revolutionised LANs.
Since then, Ethernet has been a core LAN technology, widely used even today. It is also because of the Ethernet that LANs are primarily considered wired networks.
Purpose
LANs are mostly used to connect devices in closed spaces such as a household, a school building, a university campus, an office building, etc.
Depending on the need, LANs can also extend to multiple buildings and can allow over a thousand connections.
Pros
- Relatively uncomplicated to set up
- Allows connected computers to share hardware and software resources with ease
- Easy access to shared data thanks to it being stored on a local server
- All devices on the network are authorised paving way for better network security
Cons
- Initial set-up costs are high
- Network administrators can view data on connected computers without permission
- Network span is limited due to it being localised
- Any lapse in securing the server can result in the entire network becoming vulnerable
MAN
Description
A MAN is fundamentally a collection of interconnected LANs across a metropolitan area coupled with necessary network protocols. MANs use technologies such as fibre-optics to connect clusters of LANs as well as provide further connection to a WAN (Wide Area Network).
MANs are significantly larger than LANs but small enough to enforce high data transfer speeds in an urban environment.
The “Metropolitan” in MAN doesn’t imply the limitation of this network to urban areas. It instead signifies its scale of implementation, which usually goes from 5 Km to 50 Km.
History
Metropolitan Area Networks came into existence in the years leading to the onset of the 21st century. Their purpose was to facilitate high-speed data transfer between office buildings in a city.
Businesses and organisations were already using telephone lines to interconnect their LANs and enable data communication among themselves. However, due to the slow bandwidths offered by the telephone lines and the unstable nature of the telephone network, these institutions required a new networking standard.
The first MANs were based on dark fibres, the unused fibre-optic cables owned by telephone companies and leased to office buildings.
Since then, companies have used MANs for closed communication in a city as well as attached them to gateways to offer connectivity to the internet.
Purpose
Metropolitan Area Networks are primarily used to:
- Interconnect office buildings within a town or city
- Connect public institutions such as hospitals and police departments
- Offer broadband internet connections
- Offer cable TV connections
Pros
- Less resource-intensive than other networks as it simply interconnects networks (LANs) instead of individual devices
- Data transfer rates are higher than PANs and LANs
- Wider network range than PANs and LANs
Cons
- Difficult to secure owing to a large number of connected devices and networks
- Requires dedicated personnel to set up
- Network span is limited due to it being localised
- Since the network is primarily dependent on fibre-optics, as it grows, the need for more cable arises resulting in increased costs
WAN
Description
The WAN or Wide Area Network is geographically the most extensive computer network. It is a type of network that interconnects several LANs or MANs and other less-wide networks, facilitating data transmission over long, sometimes unimaginable distances. The internet is a prime example of a Wide Area Network.
People usually refer to WANs as networks that span continents. But technically, a WAN is a network encompassing several networks, each with a different constitution.
A simple example would be an automobile firm headquartered in the US and communicating with its employees in India over a proprietary network. This proprietary network connects the LAN at the US headquarters of the firm with the LAN at its Indian office, allowing both parties to share resources and information.
History
Enterprise-level wide area networks have been in existence since the late 1970s. Back then, firms were already using leased circuits – dedicated telecommunication circuits that allow communication between two or more locations on a contractual basis – to connect their offices to a mainframe computer or data centres.
In the following years, leased lines began to offer higher speeds (up to 45 Mbps). But at the same time, they were getting too expensive for most businesses.
As a result, packet-switched networks became prominent. ARPANET, a network developed by the US Department of Defence, was the first proper packet-switched network. And it showed great promise in how it handled data distribution over great distances. Many also call it the precursor of the modern-day internet.
In 1999 the World Wide Web (WWW) appeared on the scene, courtesy of Tim Berners Lee. The WWW changed the face of computer networking, and the rest is history.
Purpose
WANs find uses in enterprise communication, helping businesses communicate with their branches in different locations over private networks. Several governments and educational institutions use WANs to implement their services.
Apart from this, ISPs (Internet Service Providers) use WANs to offer internet connectivity to individuals and organisations.
Pros
- WANs are not location-specific and can administer communication between multiple devices from different parts of the world
- Connects a host of devices regardless of their hardware/software configurations
- Widest range of all networks
Cons
- Difficult to maintain due to its range and the sheer number of connected devices
- Expensive to set up and repair
- Highly prone to network threats due to its large scale of operations
Some More Types of Computer Networks
Here we have a few more computer networks that exist owing to specific networking requirements.
CAN
CAN stands for Campus Area Network and refers to a computer network that Universities primarily use on their campuses. Some big schools and colleges also employ CANs to exchange information internally or with other institutions in their proximity.
SAN
A SAN or Storage Area Network is a type of computer network whose primary purpose is to allow devices (servers) to access data pools. It is a dedicated computer network with high data transfer rates, typically between 2Gbps and 128Gbps.
SANs consist of interconnections between switches, servers and data storage made using fibre-optics. Since a SAN is not connected to any LAN, MAN or WAN, it is free from any sort of network disruptions and bottlenecks.
SAN
Another SAN on this list, this one stands for System Area Network. It is a high-speed network that connects computer clusters – an arrangement of several computers that work cohesively as one system.
SANs are an iteration of wired LANs that offer excellent data transmission in terms of quality and speed. Their range can exist anywhere between a few metres to a few kilometres.
The Microsoft SQL Server 2005 is a classic example of a SAN in action.
POLAN
A POLAN or Passive Optical Local Area Network (or Passive Optical LAN) is a cost-effective, less power-intensive and more resilient alternative to a conventional LAN. It uses single-mode fibre-optics and optical splitters to split downstream signals and combine upstream signals.
The “passive” in POLAN refers to the fact that POLANs do not require an excessive number of power-hungry switches or amplification equipment.
All they need is only an OLT (Optical Line Terminal) on the ISP’s side, the optical splitter to split and combine signals, and an ONT (Optical Network Terminal) to convert the light signal on the fibre-optic to electric signal for your router.
VPN
Even if you are not a techie, you must have heard or used a VPN at least once in your life. A Virtual Private Network or VPN refers to a network service that encrypts your data and sends it over a public network (the internet, for example) to a given address. Upon arrival, the VPN then decrypts the received data.
The entire data transmission process, thus, looks like it was executed over a private network.
VPNs are almost essential in today’s world, safeguarding IP addresses and providing access to websites banned in certain nations.
Conclusion
So there you have it, a list of all the essential types of computer networks along with their necessary details.
All the networks listed here have different configurations and address distinct networking needs. But what they all do in common is impact several aspects of human life.
Whether it is connecting your phone to a laptop or an astronaut aboard the ISS (International Space Station) tweeting their thoughts, computer networks are everywhere. In short, they are the lifeline or the backbone of the modern world.
And as the world becomes more and more interconnected, the density and types of these networks will only increase.
