What Is a Wireless LAN?
wireless local-area network (WLAN) is a group of colocated computers or other devices that form a network based on radio transmissions rather than wired connections. A Wi-Fi network is a type of WLAN; anyone connected to Wi-Fi while reading this webpage is using a WLAN.
Is a WLAN secure? Is a WLAN secure?
A WLAN is more vulnerable to being breached than a physical network. With a wired network, a bad actor must gain physical access to an internal network or breach an external firewall. To access a WLAN, a bad actor must simply be within range of the network.
The most basic method of securing a WLAN is to use MAC addresses to disallow unauthorized stations. However, determined adversaries may be able to join networks by spoofing an authorized address.
The most common security method for a WLAN is encryption, including Wired Equivalent Privacy (WEP) and Wi-Fi Protected Access (WPA), with WPA2 as the standard authentication method.
Advantages of Wireless Network
Following are the benefits or advantages of wireless network
- ➨Wireless networks are easy to install and maintain.
- ➨They offer flexibility and mobility during usage.
- ➨The wireless signals are available behind the walls and on hilly terrains and hence it can provide service independant of location.
- ➨Prices are very low due to large number of mobile user devices from number of manufacturers.
- ➨Wireless networks cover wide coverage areas with the help of appropriate signal strength and modulation techniques.
- ➨File sharing is easier task using wireless connections such as wifi, bluetooth and so on.
- Accessibility: Wireless networks do not require any wires or cables, and hence the users can communicate even when they are moving. It allows users to roam around without getting disconnected. As a result, there is a productivity improvement.
- Easy installation: Installing a wireless network is faster and easier compared to a wired network. It also reduces the usage of cables that are difficult to set up and imposes the risk of safety since the user can trip on the wires and fall. If users want to change the network, they have to update the wireless network to meet the new configurations.
- Wider reach: Wireless networks have a wider reach than wired networks. They can be easily extended to places where wires and cables are not accessible.
- Flexibility: Setting up a wireless network helps the user to do work from home easily. Due to this network, users can work more productively and also have accessibility to customer data.
- Efficiency: Wireless networks allow improved and better communication of data. With a wireless network, the transfer of information between users is much faster.
- Cost-effective: Wireless networks are cost-effective since they are cheaper and easier to install. Even though their initial investment is high, with time, the overall expenses become lower.
- Increased Mobility: Wireless networks allow mobile users to access real-time information so they can roam around your company’s space without getting disconnected from the network. This increases teamwork and productivity company-wide that is not possible with traditional networks.
Disadvantages of Wireless Network
Following are the drawbacks or disadvantages of wireless network
- ➨Wireless network offers lower speed compare to wired network.
- ➨Wireless network offers less bandwidth compare to wired network as wireless networks use frequency spectrum which is very scarse resource.
- ➨Wireless networks are less secure compare to wired networks.
- ➨Wireless networks are prone to interference from nearby wireless networks and from other fading conditions.
- ➨Quality of service is poor due to jitter and delay in connection setup time.
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- Security: Security is a big issue while using wireless networks. If a wireless network is not installed correctly or maintained correctly, it may cause severe security threats. Connecting physical components such as wires is not required by a wireless network. They only need a wireless adapter which automatically increases the risk of hacking since hackers can have easy accessibility of the network. If there is password protection for the network, then situations may take a turn for the worse.
- Limited bandwidth: Wireless networks cannot support VTC or Video Teleconferencing since they have minimal bandwidth. It also has limited expandability since there is an absence of a wireless spectrum for occupying. The bandwidth can also get stolen by neighbors if the network is not password protected.
- Speed: The speed of the wireless network is slower than the speed of wired networks. Transferring or sharing files is much slower in a wireless network. The speed also depends on the location of the user concerning the network. The farther the user is from the network, the worse the connection becomes. This is a huge problem for large spaces or buildings.
- Cost: Wireless networks are usually inexpensive, but the cost of installation is very high. Setting up a wireless network is very costly, and sometimes there are extra costs along with it. A wireless network may require the setting up of specific equipment, which can be costly.
- Prone to interference: Due to external factors like dust storms or fog, there are high chances of interference and jamming in wireless networks. Wireless networks are highly prone to interference; therefore, fog, radiation, radio signals, or any similar interference may cause a malfunction in a wireless network. Again, when there are too many users in the same area, the air band using which the signals are transmitted can get overloaded.
- Coverage: The coverage area of a wireless network is minimal. A typical wireless router allows users within the range of 150 to 300 feet to use the network.
- Requires basic computer knowledge: Setting up a wireless network requires minimum knowledge of computers. People who are inexperienced in the computer field may face trouble installing a wireless network. There is a high risk of security, and hackers can easily hack those networks.
Wireless Networks – Questions with Answers?
This article presents a set of 50 questions (with answers) related to wireless networks
1) What is a distinguishing attribute of a wireless network as compared to a general wireless communication system?
Answer: In a wireless network, communications takes place between computer devices.
2) What types of information does a wireless network support?
Answer: E-mails, messages, web pages, database records, streaming video, and voice.
3) What are the four types of wireless networks?
Answer: Wireless PAN, LAN, MAN, and WAN.
4) What is the typical maximum range of a wireless PAN?
Answer: 50 feet.
5) True or false: A wireless PAN consumes little power from small handheld computer devices.
6) What is a common standard for wireless LANs?
Answer: IEEE 802.11 or Wi-Fi.
7) What relatively new standard applies to wireless MANs?
Answer: IEEE 802.16.
8) Why do wireless WANs not effectively satisfy requirements for indoor wireless networks?
Answer: Wireless WAN systems are generally installed outdoors, and the signals lose strength before reaching the inside of the facility.
9) What is a common application of wireless networks in homes and small offices?
Answer: Sharing Internet connections among multiple, mobile computers is a common application.
10) What are examples of applications for wireless WANs?
Answer: Access to Internet applications from outdoor locations, realestate transactions, field-service and sales calls, vending-machine status, and utility-meter reading are a few examples.
11) Which wireless NIC form factors are best for small wireless computer devices?
Answer: PC Card, Mini-PCI, and CompactFlash.
12) What are examples of elements that impair the propagation of wireless communications signals through the air medium?
Answer: Rain, snow, smog, and smoke.
13) What is the primary purpose of a base station?
Answer: Interfaces the wireless communications signals traveling through the air medium to a wired network.
14) What are common features of wireless middleware?
Answer: Optimization techniques, intelligent restarts, data bundling, screen shaping and reshaping, and end-system support.
15) On what layers of the OSI reference model do wireless networks operate?
Answer: Physical layer and data link layer.
16) How is throughput different from data rate?
Answer: Throughput doesn’t include overhead of protocols.
17) True or false: A computer device stores data in analog form.
18) A wireless NIC must convert the information into what type of signal before transmission through the air medium?
19) Which medium access protocol is common with wireless networks?
20) Explain how the ARQ form of error control works.
Answer: The receiving wireless NIC performs error checking and sends a request to the sending wireless NIC to retransmit the frame if errors are found.
21) RF signals offer relatively short range as compared to light signals. True or false?
22) What type of weather impacts RF signals the most?
Answer: Heavy rain.
23) Why does interference cause errors in wireless networks?
Answer: The interference causes the receiver to misunderstand the signal because two signals are present at the same time.
24) What are sources of RF interference?
Answer: General examples include cordless phones, microwave ovens, and Bluetooth devices.
25) Multipath affects higher data rates more than lower data rates for 2.4 GHz systems. True or false?
Answer: True. The receiver has difficulties with differentiating one bit from another when demodulating high data rate signals because the bits are close together.
26) What is meant by a diffused infrared light system?
Answer: A system that emits light in all directions that reflects off of the ceiling and walls.
27) Approximately up to what range do direct infrared systems operate?
Answer: 1 mile.
28) How does modulation make it possible to transmit information through the air?
Answer: Modulation superimposes an information signal onto a carrier signal that has a frequency suitable for propagating through the air.
29) What attributes of a signal does QAM change in order to represent information?
Answer: Amplitude and phase.
30) Spread spectrum generally requires user licenses. True or false?
31) What form factors are common for wireless PAN radio cards?
Answer: PC Card and CF.
32) What application can strongly benefit through the use of a wireless USB adapter (also referred to as a wireless dongle)?
Answer: Any application that can benefit from interfacing with a PC or laptop through the USB port, such as PDA, wireless mouse, and wireless digital camera for synchronization purposes.
33) When would the use of a wireless PAN router make sense?
Answer: For applications limited to the size of a room, such as in homes and small offices.
34) What is the general maximum coverage area of a wireless PAN?
Answer: Within 30 feet, such as within a room.
35) Which IEEE standards group uses Bluetooth as the basis for the standard?
36) In what frequency band does Bluetooth operate?
Answer: 2.4 GHz.
37) What is the primary issue of using Bluetooth around 802.11 wireless LANs?
Answer: They both operate in the same 2.4 GHz frequency band, which can result in interference and degradation in performance.
38) A Bluetooth-enabled device is always transmitting. True or false?
39) What is the highest possible data rate of an IrDA device?
Answer: 4 Mbps.
40) What is a benefit of IrDA as compared to Bluetooth?
Answer: IrDA is immune from RF interference with wireless LANs.
41) Which wireless LAN component is most commonly used in home and small offices?
Answer: Wireless LAN router.
42) What is the primary difference between an access point and a wireless LAN router?
Answer: A wireless LAN router actually routes packets to their destination. Access points don’t implement DHCP and NAT. Routers do implement DHCP and NAT.
43) When would the use of a wireless LAN repeater make sense?
Answer: When extending the range of an access point or router to an area where wires can’t be run feasibly.
44) How does a wireless LAN radio NIC identify with which access point to associate?
Answer: The radio NIC listens for beacons being sent periodically by each access point and associates with the access point having the strongest beacon signal.
45) WEP is a mandatory encryption mechanism. True or false?
46) In what frequency band does 802.11a operate in?
Answer: 5 GHz.
47) How many non-overlapping channels are available with 802.11b wireless LANs?
48) True of false: 802.11g operates at up to 54 Mbps and interoperates with 802.11b.
49) Which 802.11 frequencies are available almost worldwide?
Answer: 2.4 GHz (802.11b and 802.11g).
50) What does Wi-Fi provide?
Answer: A product having Wi-Fi certification will interoperate with other products that have Wi-Fi certification, regardless of the manufacturer.