Wireless 101 Terminology (Part 1). Implementing Cisco Unified Wireless Networking Essentials (IUWNE)

Дениз Кая

Here we are going to share some very basic information about wireless networks including terminology, different types of topologies, and design guides in a several blog posts part by part.

In the original course Implementing Cisco Unified Wireless Networking Essentials (IUWNE) you will gain the knowledge and the skills to design, install, configure, troubleshoot, and manage a small to medium-size business or enterprise class network. IUWNE course will also help you prepare for the CCNA wireless exam.

Frequency determines how of the signals are seen. All radio waves, because they are electromagnetic fields, travel at the speed of light; therefore, a wave will take longer or shorter amounts of time to travel one full cycle, or hertz, depending on its length. A signal that is 1 cm long takes less time to complete than a signal that is several meters long. If this sounds confusing, imagine sitting at an intersection waiting for a car to pass; a car travelling at 40 km/h through an intersection is gone before you have time to get impatient. If, on the other hand, you are waiting for a train 100 cars long to pass, you would be waiting for a long time even if it was travelling at 40 km/h just like the car. There is a direct relationship between wavelength and frequency: the shorter the wavelength the more often a signal can repeat itself over a given amount of time, thereby giving it a higher frequency. Note that lower frequency signals typically travel farther than higher frequency signals.

RF signals start with an electrical alternating current signal generated by a transmitter. This signal is sent to an antenna where changes in electron flow in the antenna radiate electromagnetic waves. Another antenna can receive these electromagnetic waves and translate them back into AC current. AC is electrical current that changes direction cyclically. The shape of the alternating current is a sine wave and the signal radiated by the antenna will be the same as the AC current. The distance from any point on the wave to the same point on the next wave is the signal’s wavelength. Wavelength will impact on other properties of the signal.

Amplitude is the vertical distance between the upper and lower crests of a wave. It is important to know that a signal with a given frequency and wavelength can have different amplitudes. A signal’s amplitude represents its strength or the amount of energy carried by the signal. This amplitude or energy can be absorbed by objects the signal encounters and can also diminish as the signal travels out over free space. Amplitude can be increased passively by increasing the focus or gain of an antenna or actively by increasing power applied at the transmitter. Amplitude is regulated in order to limit things such as the potential for damage to other receivers and to reduce the risk of causing interference for other networks.

In our next post on Wireless 101 Terminology you’ll read about Free Path Loss, Absortption, Reflection, Multipath, and Scattering.

To go to part 2 please visit:  Wireless 101 Terminology (Part 2). Implementing Cisco Unified Wireless Networking Essentials (IUWNE)

Deniz Kaya is a senior security instructor at New Horizons Bulgaria
Deniz has planned, directed, and coordinated multiple projects simultaneously, ensuring goals and objectives were accomplished within time limitations and funding conditions. His core competency lies in areas of penetration testing, security assessments, enterprise network design, capacity planning and vendor evaluation. Equipped with Industry recognized certification under his belt, Deniz has demonstrated his determination to continuously self-improve and make his presence felt.

Deniz currently holds the prestigious industry certifications Microsoft Certified Systems Engineer (MCSE), Certified Cisco Systems Instructor (CCSI #31650), CCIE Security Written, Cisco Certified Network Professional (CCNP), Cisco Certified Security Professional (CCSP), Cisco Ironport Certified Security Instructor (ICSI), Cisco Ironport Certified Security Professional (ICSP), Certified Penetration Testing Specialist (CPTS), Microsoft Certified Trainer (MCT).

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