What is a local area network?

LAN means Local Area Network. A local area network is a network of computers that interconnects the computer within a limited area like school, laboratory, office, and so forth. The local area network does not cover a larger distance. It shares a centralized internet connection which can be a communication cable or a wireless network.

Collection of devices to set up LAN

• A router or network switch is required.
• An ethernet cable is required to connect every device. 
• A computer system.
• Other devices to be connected.

Requirements for connecting a LAN to the internet

• A broadband connection.
• A network switch/router.
• A modem (if there is no inbuilt router).

Setting up the LAN

1. Use a router or network switch to interconnect devices.
2. Plug the router to the power source.
3. Connect the modem to the router.
4. Plug the Ethernet cable to the LAN port on the router.
5. Use the Ethernet cable to connect the devices that makes up the LAN to the router or switch.
6. The router connects to the internet automatically once it is turned on. All the devices connected to the router will be assigned an unique IP address. Once IP addresses are assigned, they can communicate with each other.
7. Now, the devices can share resources such as printers, files, folder and internet connection with one another.

Topologies of LAN

There are two types of LAN topologies:

• Physical
• Logical

Physical topology is further divided into two:

• Point to point
• Multi-point

Five different types of LAN topology are listed below:

• Star-A star topology is a network topology in which each network component is physically connected to a central node, such as a router, hub or switch.
• Mesh-In a mesh topology, each node is connected to every other node using a dedicated line.
• Bus-A bus network is an architecture in which nodes are connected to a shared half-duplex bus directly.
• Ring-A ring topology is a network configuration that connects devices in a circle to form a circular data channel.
• Hierarchical-A hierarchical or extended star topology is a star network in which an additional level of networking device is connected to the main networking device.

Resource sharing through LAN

Using LAN resources such as devices, images, videos, files and so forth can be shared. Networking is done by setting up a LAN interconnecting those devices. Networking is the exchanging of data between the nodes which are interconnected by means of wired or wireless medium. On Windows PCs (personal computers) it is easy to set up the sharing mode by creating a homegroup.

Select Start -> Control Panel->Network and Internet->Homegroup in order to a homegroup. In the setup wizard a password is provided which is used by other devices in order to connect to the Homegroup.

While setting up the homegroup, it involves specifying the kinds of files can be able to share. There are many ways to share using LAN:

• Click right-clicks on the file/folder that needs to be shared, then select Share to nearby device using Bluetooth / WiFi.
• Under the Advanced Sharing settings in the Network and Sharing Center move the files to the public folder.
• In Mac, go to System Preferences->Sharing Preferences->File Sharing. Add the files to the shared folder.
• Connect any storage device to the USB port of the router and share the content of the USB to other devices connected to the router.

Benefits

• Computer resources such as printers, scanners, modems, DVD-ROM drives, and hard discs can be shared over LAN. It provides a simple and flexible way for sharing resources.
• Rather than buying and installing a individual licensed copy of software for each node connected to the network, it is simple to use the same software on a number of computers connected to the network.
• Data and messages can be easily shared with other computers on the network at a low cost.

Drawbacks

• Expensive Initial Setup Costs: Because special software is necessary to construct a server, the initial setup costs of installing Local Area Networks are high. Communication hardware such as ethernet cables, switches, hubs, routers, and cables are very expensive.
• Privacy Infringements: The LAN administrator has access to each and every LAN user's personal data files.
• Unauthorized users can gain access to sensitive data stored on a server hard disk, if the LAN administrator fails to properly safeguard it.

Context and Applications

This topic is important for postgraduate and undergraduate courses, particularly for,

• Bachelors in computer science engineering.
• Associate of science in computer science.

Practice Problems

Question 1: What is AP(access point) in LAN?

1. Nodes in the network
2. Wireless devices
3. Device that connects wireless devices to a wired network
4. None of these

Answer: Option C is correct.

Explanation: An access point is a device that allows the wireless devices to get connected to the wired network in a wireless network.

Question 2: __________ is an example of ad-hoc network

1. Ethernet based network
2. Bluetooth
3. GSM network
4. None of these

Answer: Option B is correct

Explanation: Bluetooth enable spontaneous connection between nearby devices for sharing resources.

Question 3: What is the IEEE 802.11 standard for wireless LAN?

1. CSMA/CA
2. CDMA
3. ALOHA
4. None of these

Answer: Option A is correct.

Explanation: CSMA/CA- carrier sense multiple access/collision avoidance.

Question 4: Which device connects to the internet automatically when it is powered on?

1. Router
2. Network switch
3. Hub
4. None of these

Answer: Option A is correct.

Explanation: Router connects to the internet once it is powered on.

Question 5: Expand WEP?

1. Wired Equivalent Privacy
2. Wireless Equivalent Privacy
3. Wide Equivalent Privacy
4. None of these

Answer: Option A is correct.

Explanation: WEP - wired equivalent privacy is a security algorithm for wireless networks. It provides better data security compared to other wired networks.