Listed below is a summary of what you will need to know about WLANs for the ICND1 Exam.
- One of the main reasons to install a Wireless LAN is cost reduction.
- Another reason is because it allows employees to move their computers to different locations in the office and it requires no moving of cables on your part.
- Wireless LANs use CSMA/CA – Carrier Sense Multiple Access with Collision Avoidance instead of CSMA/CD
- RTS – Ready To Send
- CTS – Clear To Send
- WLANs have a larger Layer 2 Header
- WLANs can have range problems
- WLANs can receive interference from other wireless devices
- WLANs can have more security problems
- Reflection -
- Scattering -
- Absorption -
- SNR – Signal-to-Noice-Ratio
- To double the range of an access point you have to quadruple the current power level
- The higher the frequency the shorter the range
- 900mhz ISM Bands
- 5Ghz UNII – Unlicenced National Information Infrastructure Band
- EIRP – Effective Isotropic Radiated Power – To compute the EIRP=Transmitter Power + Antenna Gain – Cable Loss
- 802.11b uses DSSS – Direct Sequence Spread Spectrum
- To not overlap wireless signals you need a separation of at least 5 channels
- CCK – Complimentary Code Keying
- 801.11a uses OFDM – Orthogonal Frequency Division Multiplexing
- Wi-Fi Alliance – A global non profit
Related Topics:
ICND1 Study Guide – The Fastest Way To Get Cisco Certified Guaranteed!