Wireless Networking—NETWORKING ESSENTIALS—CompTIA A+ (220-1001) A-PLUS Certification Prep Course Notes
Wireless Networking
- Wireless Network Hardware
- A wireless access point (WAP) bridges 802.11 and Ethernet networks
- Wireless clients connect to WAPs
- 802.11 works in one of two modes:
- infrastructure mode, or
- ad hoc mode
- Use correct antenna for the job
- In many of today’s laptops the antenna is built into the laptops monitor itself.
- (SSID)-Service Set Identifier (SSID)
- Wi-Fi Standards
- 802.11 uses the 2.4- and 5-GHz ISM band
- 802.11 uses remade channels
- Memorize the band usage and relative speeds of the 802.11 extensions.
- (ISM) Industrial, Scientific, and Medical Radios Bands
- 2.4 GHz and 5 GHz Band
- Band is a range of radio frequencies
- 2.4 GHz Band: 2.412-2.4884 GHz
- Uses different “channels”
- 5 GHz Band: 5.150 – 5.875 GHz
- Also uses different channels
- MIMO (Multiple-Input Multiple-Output)
- 802.11ac
- Multi-User MIMO
- 802.11n
- Wi-Fi 4
- 802.11ac
- Wi-Fi 5
Standard | Speed | Band |
802.11a | 54 Mbps | 5 GHz |
802.11b | 11 Mbps | 2.4 GHz |
802.11g | 54 Mbps | 2.4 GHz (802.11g is backwards compatible with 802.11b 2.4 GHz.) |
802.11n | 100 Mbps | 2.4 GHz & 5 GHz (802.11n is backwards compatible with all the others.) |
- Basic WAP Setup
- A site survey shows available channels in a ISM band
- You must create a service set identifier (SSID)
- Most WAPs support multiple SSIDs
- You can also hide SSID broadcasts
- You can define extensions to support, channels, and channel width.
- We can use WiFi analyzers to perform a site survey.
- ex: “WiFiman” from Ubiquity Networks company
- SSID (Service Set Identifier)-“name of the wireless network”
- Connecting to a Wi-Fi Network
- All wireless clients can scan the 802.11 spectrum, finding available SSIDs
- You must know the SSID and password to connect
- Clients create profiles that store the SSIDs and their passwords
- It’s a Huge Mesh
- Mesh Networks are often a great wireless solution for SOHO environments
- Mesh networks have a base station & beacon devices that connect to the base station
- Mesh networks use their own encryption
- Mesh networks are universally easy to configure.
- WMN (Wireless Mesh Network)
- Beyond Wi-Fi
- RFID uses tiny radios activated by the energy of the scanning device
- NFC requires extremely close proximity to function
- Bluetooth is like 802.11 but pairs with devices to function as point-to-point.
- RFID (Radio Frequency Identification)
- NFC (Near Field Communication) NFC is RFID.
- used to “Tap to print” functions or “Tap to pay”
- PAN (Personal Area Network)—Bluetooth
- Bluetooth classes
- Class —> Power —> Range
- Class 1 —> 100mW —> 100m
- Class 2 —> 2.5mW —> 10m
- Class 3 —> 1mW —> 1m
- Troubleshooting Wireless Connections
- The CompTIA A+ exams list specific wireless errors
- Wi-Fi analyzers are very helpful to diagnose wireless problems