WLAN Concepts

WLAN Concepts

1. Introduction to Wireless

   • Benefits of Wireless
     • A Wireless LAN (WLAN) is a type of wireless network that is commonly used in homes, offices, and campus environments.
   • Types of Wireless Networks
     • WPAN WLAN WMAN WWAN
   • Wireless Technologies
     • -Bluetooth -WiMAX -Cellular Broadband -Satellite Broadband
   • 802.11 Standards
     • These standards define how radio frequencies are used for wireless links.
   • Radio Frequencies
     • WLAN networks operate in the 2.4 GHz frequency band and the 5 GHz band.
   • Wireless Standards Organizations
     • Standards ensure interoperability between devices that are made by different manufacturers.
       • ITU IEEE Wi-Fi Alliance

2. WLAN Components

   • Wireless NICs
     • 1) End devices with wireless NICs 2) A network device, such as a wireless router or wireless AP
   • Wireless Home Router
     • Access point Switch Router
   • Wireless Access Points
     • While range extenders are easy to set up and configure, the best solution would be to install another wireless access point to provide dedicated wireless access to the user devices.
   • AP Categories
     • Autonomous APs
     • Controller-based APs
   • Wireless Antennas
     • -Omnidirectional Antennas -Directional Antennas -MIMO Antennas

3. WLAN Operation

   • 802.11 Wireless Topology Modes
     • -Ad hoc mode -Infrastructure mode -Tethering
   • BSS and ESS
   • 802.11 Frame Structure
     • -Frame Control -Duration -Address1 -Address2 -Address3 -Squence Control -Address4 -Payload -FCS
   • CSMA/CA
     • Method to determine how and when to send data on the network.
   • Wireless Client and AP Association
     • For wireless devices to communicate over a network, they must first associate with an AP or wireless router.
   • Passive and Active Discover Mode
     • In passive mode, the AP openly advertises its service by periodically sending broadcast beacon frames containing the SSID
     • In active mode, wireless clients must know the name of the SSID.

4. CAPWAP Operation

   • Introduction to CAPWAP
     • CAPWAP is an IEEE standard protocol that enables a WLC to manage multiple APs and WLANs.
   • Split MAC Architecture
     • AP MAC Functions WLC MAC Functions
   • DTLS Encryption
     • Allows to AP and the WLC to communicate using encryption and prevents eavesdropping or tampering.
   • FlexConnect APs
     • FlexConnect is a wireless solution for branch office and remote office deployments

5. Channel Management

   • Frecuency Channel Saturation
     • DSSS FHSS OFDM
   • Channel Selection
   • Plan a WLAN Deployment

6. WLAN Threats

   • Wireless Security Overview
     • Attacks can be generated by outsiders, disgruntled employees, and even unintentionally by employees.
   • DoS Attacks
     • Accidental interference
     • A malicious user intentionally interfering with the wireless communication
     • Improperly configured devices
   • Rogue Access Points
     • A rogue AP is an AP or wireless router that has been connected to a corporate network without explicit authorization and against corporate policy.
   • Man-in-the-Middle Attack
     • In a man-in-the-middle (MITM) attack, the hacker is positioned in between two legitimate entities in order to read or modify the data that passes between the two parties.

7. Secure WLANs

   • SSID Cloaking and MAC Address Filtering
   • 802.11 Original Authentication Methods
     • The best way to secure a wireless network is to use authentication and encryption systems.
   • Shared Key Authentication Methods
     • -Wired Equivalent Privacy (WEP) -Wi-Fi Protected Access (WPA) -WPA2 -WPA3
   • Authenticating a Home User
     • Personal Enterprise
   • Encryption Methods
     • Temporal Key Integrity Protocol (TKIP) Advanced Encryption Standard (AES)
   • Authentication in the Enterprise
     • RADIUS Server IP address UDP port numbers Shared key
   • WPA3
     • -WPA3-Personal -WPA3-Enterprise -Open Networks -Internet of Things (IoT) Onboarding