Introduction to Wireless
Summary
This topic describe WLAN technology and standards. Start learning CCNA 200-301 for free right now!!
Note: Welcome: This topic is part of Module 12 of the Cisco CCNA 2 course, for a better follow up of the course you can go to the CCNA 2 section to guide you through an order.
Table of Contents
Benefits of Wireless
A Wireless LAN (WLAN) is a type of wireless network that is commonly used in homes, offices, and campus environments. Networks must support people who are on the move. People connect using computers, laptops, tablets, and smart phones. There are many different network infrastructures that provide network access, such as wired LANs, service provider networks, and cell phone networks. But it’s the WLAN that makes mobility possible within the home and business environments.
In businesses with a wireless infrastructure in place, there can be a cost savings any time equipment changes, or when relocating an employee within a building, reorganizing equipment or a lab, or moving to temporary locations or project sites. A wireless infrastructure can adapt to rapidly changing needs and technologies.
Types of Wireless Networks
Wireless networks are based on the Institute of Electrical and Electronics Engineers (IEEE) standards and can be classified broadly into four main types: WPAN, WLAN, WMAN, and WWAN.
Click each wireless network type for more information.
Wireless Personal-Area Networks (WPAN) - Uses low powered transmitters for a short-range network, usually 20 to 30 ft. (6 to 9 meters). Bluetooth and ZigBee based devices are commonly used in WPANs. WPANs are based on the 802.15 standard and a 2.4-GHz radio frequency.
Wireless LANs (WLAN) - Uses transmitters to cover a medium-sized network, usually up to 300 feet. WLANs are suitable for use in a home, office, and even a campus environment. WLANs are based on the 802.11 standard and a 2.4-GHz or 5-GHz radio frequency.
Wireless MANs (WMAN) - Uses transmitters to provide wireless service over a larger geographic area. WMANs are suitable for providing wireless access to a metropolitan city or specific district. WMANs use specific licensed frequencies.
Wireless Wide-Area Networks (WWANs) - Uses transmitters to provide coverage over an extensive geographic area. WWANs are suitable for national and global communications. WWANs also use specific licensed frequencies.
Wireless Technologies
Wireless technology uses the unlicensed radio spectrum to send and receive data. The unlicensed spectrum is accessible to anyone who has a wireless router and wireless technology in the device they are using.
Click each wireless technology for more information.
Bluetooth - An IEEE 802.15 WPAN standard that uses a device-pairing process to communicate over distances up to 300 ft. (100m). It can be found in smart home devices, audio connections, automobiles, and other devices that require a short distance connection. There are two types of Bluetooth radios:
- Bluetooth Low Energy (BLE) - This supports multiple network technologies including mesh topology to large scale network devices.
- Bluetooth Basic Rate/Enhanced Rate (BR/EDR) - This supports point to point topologies and is optimized for audio streaming.
WiMAX (Worldwide Interoperability for Microwave Access) - WiMAX is an alternative to broadband wired internet connections, competing with DSL and cable. However, it is typically used in areas that are not yet connected to a DSL or cable provider. It is an IEEE 802.16 WWAN standard that provides high-speed wireless broadband access of up to 30 miles (50 km). WiMAX operates in a similar way to Wi-Fi, but at higher speeds, over greater distances, and for a greater number of users. It uses a network of WiMAX towers that are similar to cell phone towers. WiMAX transmitters and cellular transmitters may share space on the same tower, as shown in the figure.
Cellular Broadband - Cellular 4G/5G are wireless mobile networks primarily used by cellular phones but can be used in automobiles, tablets, and laptops. Cellular networks are multi-access networks carrying both data and voice communications. A cell site is created by a cellular tower transmitting signals in a given area. Interconnecting cell sites form the cellular network. The two types of cellular networks are Global System for Mobile (GSM) and Code Division Multiple Access (CDMA). GSM is internationally recognized, while CDMA is primarily used in the US.
The 4th Generation GSM network (4G) is the current mobile network. 4G delivers speeds that are 10 times the previous 3G networks. The new 5G holds the promise of delivering 100 times faster speeds than 4G and connecting more devices to the network than ever before.
Satellite Broadband - Provides network access to remote sites through the use of a directional satellite dish that is aligned with a specific geostationary Earth orbit satellite. It is usually more expensive and requires a clear line of sight. Typically, it is used by rural homeowners and businesses where cable and DSL are not available.
802.11 Standards
The world of wireless communications is vast. However, for particular job-related skills, we want to focus on specific aspects of Wi Fi. The best place to start is with the IEEE 802.11 WLAN standards. These standards define how radio frequencies are used for wireless links. Most of the standards specify that wireless devices have one antenna to transmit and receive wireless signals on the specified radio frequency (2.4 GHz or 5 GHz). Some of the newer standards that transmit and receive at higher speeds require access points (APs) and wireless clients to have multiple antennas using the multiple-input and multiple-output (MIMO) technology. MIMO uses multiple antennas as both the transmitter and receiver to improve communication performance. Up to four antennas can be supported.
Various implementations of the IEEE 802.11 standard have been developed over the years. The table highlights these standards.
| IEEE WLAN Standard | Radio Frequency | Description |
|---|---|---|
| 802.11 | 2.4 GHz |
|
| 802.11a | 5 GHz |
|
| 802.11b | 2.4 GHz |
|
| 802.11g | 2.4 GHz |
|
| 802.11n | 2.4 GHz 5 GHz |
|
| 802.11ac | 5 GHz |
|
| 802.11ax | 2.4 GHz 5 GHz |
|
Radio Frequencies
All wireless devices operate in the radio waves range of the electromagnetic spectrum. WLAN networks operate in the 2.4 GHz frequency band and the 5 GHz band. Wireless LAN devices have transmitters and receivers tuned to specific frequencies of the radio waves range, as shown in the figure. Specifically, the following frequency bands are allocated to 802.11 wireless LANs:
- 2.4 GHz (UHF) – 802.11b/g/n/ax
- 5 GHz (SHF) – 802.11a/n/ac/ax
The Electromagnetic Spectrum
Wireless Standards Organizations
Standards ensure interoperability between devices that are made by different manufacturers. Internationally, the three organizations influencing WLAN standards are the ITU-R, the IEEE, and the Wi-Fi Alliance.
Click each button for more information about the standards organization.
The International Telecommunication Union (ITU) regulates the allocation of the radio frequency spectrum and satellite orbits through the ITU-R. ITU-R stands for the ITU Radiocommunication Sector.
The IEEE specifies how a radio frequency is modulated to carry information. It maintains the standards for local and metropolitan area networks (MAN) with the IEEE 802 LAN/MAN family of standards. The dominant standards in the IEEE 802 family are 802.3 Ethernet and 802.11 WLAN.
The Wi-Fi Alliance is a global, non-profit, industry trade association devoted to promoting the growth and acceptance of WLANs. It is an association of vendors whose objective is to improve the interoperability of products that are based on the 802.11 standard by certifying vendors for conformance to industry norms and adherence to standards.
Glossary: If you have doubts about any special term, you can consult this computer network dictionary.
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