Computer Networks

Computer Netwoorks LAN WAN CLoud

 

As soon as we humans started understanding the importance to record, the concept of Network was embedded into our system. Earliest recording of events is dated back to during the early prehistoric age in form of hieroglyph. Not exactly sure what triggered our ancestors to start drawing hieroglyph, but we can take a guess that they wanted to pass on the information. The information that they had gathered from all those years of experience, considered to be important, was recorded to pass on to the next generation or their fellow beings. We need to understand that those hieroglyphs or writings were also a form of information (or data as we may call it now), an extremely critical one in-deed. One person shared his knowledge with another and someone recording it, gave birth to the idea of channeling the information through Networking.

Fast forward to Year 1960, the world of 1’s and 0’s was taking the world bystorm. As we understood the power of computing and the impact it can have on the processed information, it raised a need to share that information more effectively. It was the year 1965 when two computers at MIT Lincoln Lab communicated with one another using packet-switching technology. Somewhere around early 1970’s the LAN (as we know it now) was developed. It was Year 1973 when the term internet is born. It has been an on going saga to share and collaborate on known information more and more effectively and efficiently. Every year we have grown and every decade we have taken a lead to process the information in a better way. Now that we have a brief history, a very brief in fact, it is time to know What Is a Network.

What Is a Network

If we were to explain a computer network in the broadest sense, a network is two or more interconnected group of people or things sharing meaningful information with one another. From a technology perspective, network is usually used for computing device or a data network. A network is nothing more than two or more computers (a group maybe) connected to each other with the purpose of transmitting, exchanging, processing, and/or sharing data and resources. A network can be formed wither via cables i.e., the wired network or without cables i.e., the wireless network. The term wired or wireless is used as a synonym to Network. Networking can be described as the practice of exchanging data between computing devices over a shared medium. A computer network enables our devices to be connected to each other on a local area network – LAN or to a larger network, such as the internet known as WAN. The telephone calls, to text messaging, to streaming or watching video on the internet, or even reading this post at instaelearn.com are the possible only due to Computer Network. Now that we understand what a Network is let us look into what are the different types of Network.

Types Of Network

There are many types of Network. They are categorized based on its intended purpose or characteristic and size. When we were describing what is a network we mentioned “LAN” and “WAN”. These are the two most used words when we talk about Network, but there are other type of Networks as well.

    • LAN/WLAN/PAN
    • WAN
    • MAN
    • SAN

Now that we know the types of LAN let’s try to understand what these actually mean, and where does it best fit for usage.

LAN/WLAN/PAN:

LAN stands for Local Area Network, WLAN stands for Wireless Local area Network, and PAN -for Personal Area Network. After p2p, which is the smallest Network topology, these are the 3 major building chunks of the network. If we were to compare Network with construction, if computing nodes such laptop, desktop, printer, phone etc are bricks then LAN, WLAN, or PAN are the floors of the building.

Both LAN and WLAN describe a network that is locally connected. A group of devices connected within a limited physical area is called LAN. It can be your home, school/college campus or office building. Each node participating in sharing information (except p2p), will be part of a LAN. The components involved in LAN can be laptop, desktop, phone, tablet, network printer, TV, gaming console, hubs & switches, wireless router etc. When all these devices are connected, they form a LAN. LAN is categorized by the signal transmission medium or the logical way in which data travels through the network between devices. Now depending on how you connect them differentiates them from being LAN and WLAN. Devices connected via cables are simply called LAN and devices connected wirelessly are called part of a WLAN. It is to be noted, in general terms, if the devices connected wirelessly connect back to same network as of wired network, and they are considered to be part of same LAN.

The function of LAN is to connect computers together and provide shared access to data and other shared devices such as printers. LAN usually runs on a client server model, except for peer-to-peer connection model. In a client-server model, multiple devices are connected in a location, privileged to access other devices, data, and network services unless specifically denied. Two LANs can be interconnected with other or multiple LAN’s can be meshed with MPLS links and services, or even across over the Internet using virtual, private network technology. This system of connected LANs is classified as a metropolitan area network, which we will discuss further below. Local Area and Metropolitan Area Networks differ in their range and capacity.

PAN on the other hand takes it to one notch smaller than LAN, we would say. PAN stands for Personal Area Network. A PAN connects a single user’s personal devices such as a laptop connected to a smartphone, tablet, or a PDA (Personal Digital Assistant) connected to a phone/tablet etc. These connections can be wired or wireless in nature ranging from USB cable to Bluetooth connection or airplay for Mac. The range of PAN can expand can range from a couple of centimeters to some meters. A PAN network device is not connected to Internet directly, however but one of the devices might be part of LAN which further connects to Internet, providing internet access to devices connected within a PAN.

WAN:

WAN stands for Wide Area Network. In general terms we call it Internet, but we need to understand Internet is not WAN instead it’s a type of WAN. WAN is another important computer network which is spread across geographical area, unlike its smaller counterpart LAN. It can be a network system that is, connection of two or more LAN’s via an ethernet/fibre cables or even radio waves. We can describe WAN as a large network that is not tied to a single location. WANs can facilitate communication, between devices across the globe. Now-a-days it is quite common for business to go international, with that arises the need for communication and central repository for database where people can start working from around the world. WAN can also facilitate creation of DR sites which can be on another side of the globe and can be accessed in case of some emergency or natural calamity. This is otherwise known as High-Availability, which we discussed earlier. The way you access your university website, watch videos on Youtube, share posts on Facebook or send an email, is also leveraging the power of WAN.

These networks are established by internet service providers (ISP) that is then leased to businesses, schools, governments, or public. These customers can use the network to transmit data with other users, no matter their location, if they have access subscribed to the WAN. Access can be granted via different methods, such as virtual private networks or leased lines, wireless networks, cellular networks, or broadband connection. Now-a-days it is quite common for business to go international, with that arises the need for communication and central repository for database where people can start working from across the globe. WAN can also create DR sites which can be on another side of the world and can be accessed in case of some emergency or natural calamity. This is otherwise known as High-Availability. The way you access your university website, watch videos on Youtube, share posts on Facebook or send an email,or read this post is also leveraging the power of WAN.

MAN:

MAN stands for metropolitan area network. It is a computer network that connects 2 more LAN’s within a city/town area. With that we can comprehend that MAN is larger than a LAN but also smaller than a wide area network (WAN). Given its name, MAN need not be in a urban area. It is to be noted MAN does not implies demographics of a network where it serves, but the size of the network. Alike WAN a MAN is also made up of interconnected LAN. MANs are usually extremely efficient and can provide fast communication with help of high-speed carriers, such as fiber cables between multiple LANs. Usually, these cables or radio are laid/provisioned by private/public-sector Internet service providers. These are then leased to their customers further as services to interconnect their offices/schools/university etc on a different part of the city/town. In some cases, this model is reversed i.e., a city government builds and maintains a metropolitan fibre network and then leases to private companies.

The working mechanism of a MAN is remarkably similar to that of WAN. But still it is vastly different because in most of the cases the MAN run in layer 2 of OSI model, where is LAN operates in Layer 3 of OSI model. When it comes to service providers usually you will notice a push from them to use WAN services and solutions instead of MAN, due to costing incurred in provisioning and maintenance reasons. At the same time, as consumers, a MAN network would mean less investment into other aspects like firewall, data centralization, router and its services and subscription.

Usually there are no hard coded limits to MAN, but usually its in a diameter of about 2 – 50 km in diameter. The speed of MANis higher than that of WAN since it comprises of already well planned location or LAN’s. It gives a good efficiency to data transfer, as data is easily manageable and is centralized. Moreoever, internet can be easily shared by a single user with other users in a MAN, if he is connected to WAN. As compared to LAN, MAN is less secured as prone to attention from attackers. At the same time MAN is more secured than a WAN.

SAN:

SAN stands for Storage Area Network. It is a specialized solution for high-speed and efficient network to provide network access to storage. It consists of interconnected hosts and storage devices along with networking/security equipment. SAN is a block-based storage that connects multiple servers to a logical disk unit or LUNs (logical unit number). SAN presents a storage solution to devices as if the storage is locally attached, which are called as blocks. A server can format and partition these blocks with a file system that its OS uses/supports so that it can store the data. A SAN can improve the storage ability and availability of a server as, it makes sure there is no single point of failure making SANs resilient and highly available. A single cable or single device fail cannot cause an outage in SAN.

In a SAN the hard disk’s on which data is stored is considered as a single resource. The servers inside a SAN can access any disks within which is helpful in increasing efficiency and utilizing the data and more efficiently. A SAN can scale up to thousands of disks which directly increases the servers potential, if having the right hardware. There are two types of network technology that runs SAN, namely; Fibre channel (FC) and ISCSI. The former is a high-speed network known for its mind-boggling throughput rates, scaling up to 128 Gbps. It is to be noted that distance plays an important role in achieving such data transfer rates and somewhere between 8-10 km is considered ideal for such achieving such throughput. An FC offers a unique and highly specialized network design. By no means, the later ISCSI is slower, it can be scaled up to a 100 Gbps. Though a bit slow as compared to standards of its counterpart FC, ISCSI provides a lot of other simplification for DC operators. The slower speeds are due to as it rides on same copper cables and Ethernet technology. The ISCSI is more flexible as it can integrate with LAN more easily and is cost effective as well. SAN can also run over LAN.

Summary

In recent years another type of network is gaining popularity. It is known as the cloud-based network. In this model, a company pays a vendor to store data, applications and other important resources such as network firewall or endpoint protection solutions on servers and manages those resources on their behalf. From a organizations perspective cloud-dependent network is cheaper, and greener than a traditional in-house network since they don’t have to spend money buying and aquiring manpower in maintaining its own servers. However, it is to be noted that it’s not necessarily the right solution for every organization.

Data is the most crucial piece in the world of computing. This makes computing networks most important to all businesses. Be it running as a SOHO, SMB or an Enterprise, data networks provide a means of faster and easier access to any message or data that can be recorded and stored in digital format. With the burst of internet and business going global to capture new markets, it is quite common for colleagues to be miles apart. This makes data sharing a significant logistical problem in the absence of a network. You don’t want to post an USB flash disk containing your research work to your colleagues in different country for them to work on the same file or sending it your boss for approval. Additionally computer networks also enable us to share resources such as network printer, storage solutions which helps organization save a lot of money in long run, rather than providing each user a single PDA, such as printer, scanner etc. For industry that requires employees to use computers with powerful computing capability for resource intensive task, shared servers are used in as a solution. It is much cheaper than to run individual printer/scanner/servers for every users.

On this note we are bringing this post to end. Hope this was informative.

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