Certified Wireless Network Administrator (CWNA)

Discover how the IETF uses the RFC process to turn ideas into standards and best practices. See how protocol standards and IP addressing concepts guide network design and internet operation.

Explore keying methods used in wireless signaling, including amplitude shift keying (ASK), frequency shift keying (FSK), and phase shift keying schemes, and learn how receivers detect ones and zeros.

Demonstrate how wavelength relates to frequency through the speed of light, using lambda = c / f and c = 300,000,000 m/s, so higher frequency means a smaller wavelength.

Signals reflect off surfaces larger than the wave, creating multipath through delayed copies, including AM radio skywave and microwave reflections.

Apply rule of three and ten to power, showing how a 3 dBi gain doubles 100 mW to 200 mW, while a 3 dB loss halves it to 50 mW.

Explain the rules of tens and threes for dbm and milliwatts using a conversion table, illustrating doubling and halving, then apply to a wireless bridge with loss and gain.

Trace how to convert 50 mW to dB, apply a -1 dB loss and a +5 dB gain, and determine the resulting power to understand transmitter gains and coverage area.

Measure antenna beam width by locating the strongest point on a 360-degree chart and tracing to where the signal drops by minus 3 dB, yielding the beam width angle.

Explore how planar antennas provide targeted coverage for long hallways and rows of offices, using semi directional beams and appropriate beam width to optimize access points.

The lecture surveys the original IEEE 802.11 standards, detailing the physical layer and MAC sublayer, and contrasts infrared as a light-based medium with FHSS and DSS spread spectrum methods.

Explore 802.11a’s high-speed 5 GHz unlicensed operation, compare it with 2.4 GHz, and explain 100 MHz channel sizing and OFDM to boost data rates and adoption choices.

Explore 60 GHz wireless technology as a high-throughput, unlicensed-band solution with physical and mac layer enhancements, delivering up to seven gigabits per second for short indoor connections.

Compare narrow band and spread spectrum to understand how bandwidth shapes channel design and interference prevention, with FCC guidelines ensuring space between frequencies.

Explore how five gigahertz channels support 802.11a/n/ac, and how guard bands separate uni one and uni two, with 30 MHz spacing from band edges and 20 MHz in uni three.

Explore adjacent, nonadjacent, and overlapping channels in a wireless LAN. Design roaming-friendly cell coverage by using non-overlapping frequencies, such as channels 1, 6, and 11.

Explore extended service sets that link two or more basic service sets via a distribution system medium, uniting access points and client stations; roaming can interrupt connections.

Explore how roaming between access points with co-location affects a user’s connection, requiring re-association and causing brief service disruption, including voice over IP calls.

Compare collision avoidance and collision detection in wireless and wired networks, highlighting half duplex limits and how CSMA/CA and CSMA/CD use media access control to manage access.

The distributed coordination function is the fundamental and mandatory access method for 802.11 communications, with optional methods like PCF and the hybrid coordination function (HCF).

Explain interframe space and its six types, highlighting reduced interframe space for QoS, SIFS, PCF interframe space, DIFS, arbitration interframe space, and extended interframe space for corrupted frames.

Explore block acknowledgement requests that allow aggregating acknowledgements for multiple frames, improving efficiency, with immediate block acks for low latency traffic and delayed block acks for file transfers.

Explore the data link layer and its two sublayers: the logical link control (LLC) that interfaces with layer three, and the MAC address sublayer that handles media access.

Explore how control frames within 802.11 manage power saver signaling, clear to send, and block acknowledgments, while contrasting DCF, PCF, and HCF for contention-free, QoS-enabled frames.

Examine data frame subtypes, including data, null data, acknowledgments, and polls, plus PCF control frames, and how quality of service boosts efficiency and access-point preference.