Before going into the main topic let me first discuss what is LAN. LAN is a short form of local area network. Local area network is a network for connecting computers and other computer accessories with each other. Computer accessories include printers, scanners, game consoles etc. LAN is used to make the connection of computers within one building. To make the connection between the computers we use communication devices and cables. Communication devices are hubs, switches, and routers. Ethernet cables are connected to hubs, switches, and routers by rj45 ports.
What is a virtual local area network (VLAN)
In a virtual area network, different switches of LAN are logically connected to each other to make the single switch. This type of network is used to logically differentiate and limit the different level of computers. For example, there are different departments in the office like the accounting department, support department, and administrative department. All the computers of these departments are logically connected to the same switch but one department computer cannot access another department computer. So same department computers can communicate with each other but different department computers cannot communicate with each other.
Advantages of local area network (LAN)
Sharing of resources:
All the resources are attached to one network and if any computer needs any resources then it can be shared with the required computer. Types of resources are the DVD drive, printers, scanners, modems and hard drives. So there is no need to purchase separate resources for each computer and it saves money.
Client and server relationship:
All the data from attached computers can be stored in one server. If any computer (Client) needs data then that computer user can simply log in and access the data from the server. For example movies and songs can be stored on the server and can be accessed by any authorized user (Client computer).
Sharing of the internet:
In offices and net cafes, we can see that one internet connection is shared between all computers. This is also the type of LAN technology in which main internet cable is attached to one server and distributed amoung attached computers by the operating system.
Software program sharing:
Software programs can also be shared on the LAN. You can use single licensed software and any user can use it in the network. It is expensive to buy a license for each user in the network so sharing software program is easy and cost-effective.
Securing of data:
Keeping data on the server is more secure. And if you want to change or remove any data you can do it easily on one server computer and other computers can access updated data. You can also give access or revoke access to specific users so that only authorized users can access the data in the network.
Communication is easy, fast, and time-saving:
In LAN computers can exchange data and messages in the easy and fast way. It also saves time and makes our work fast. Every user can share messages and data with any other user on LAN. The user can log in from any computer on the network and access the same data placed on the server.
Computer identification:
Each computer is given a MAC address and is temporarily stored in the switch or router during communication. All computers on the LAN are identified by MAC addresses which are used to send and receive messages and data. Note that MAC address is stored in the network adapter that is attached in the motherboard of each computer. In old computers, network adapters were not built in with motherboards but in modern computers, they come built-in with motherboards.
Disadvantages of local area network (LAN)
Data security problem:
If the server computer is not set up correctly and there is a leak in security then unauthorized users can access the data also. So there should be privacy policy and rules set up correctly on the server.
Limitation of distance:
Local area networks are usually made within a building or nearby building and cannot extend to the wider area.
Server crashes may affect all computers:
If any file on the server is corrupted or hard drive fails then all the attached computers face problems in functioning properly.
Setting up a LAN is expensive:
It is expensive to set up LAN because there is special software required to make a server. Also, communication devices like hubs, switches, routers, cables are costly. The special administrator is required to maintain and troubleshoot LAN for a large office.