a) If tasked with conducting a survey on security awareness and competency related to Wireless LAN (WLAN) security mechanisms and protocols, particularly focusing on Wireless hotspots/WLANs within a residential area, several approaches can be considered. Firstly, employing a questionnaire or interview method to directly engage with WLAN owners can provide insights into their security practices and awareness levels. Questions may pertain to password strength, encryption protocols utilized, and awareness of potential security threats. Additionally, conducting network scans using specialized software tools like Wireshark or Kismet can help identify security vulnerabilities and assess encryption levels of the WLANs. Furthermore, observation and documentation of physical security measures such as router placement and access restrictions can complement the survey findings.

b) Wireless Denial-of-Service (DoS) attacks targeting the Medium Access Control (MAC) layer disrupt network communication by overwhelming the network with excessive traffic or exploiting vulnerabilities in the MAC protocol. One approach involves MAC address spoofing, where the attacker impersonates legitimate devices to gain unauthorized access to the network, leading to congestion and service disruption. Another method is deauthentication or disassociation attacks, where the attacker sends forged deauthentication frames to legitimate devices, causing them to disconnect from the network. Additionally, jamming attacks flood the wireless channel with interference signals, rendering it unusable for legitimate communication. Each of these approaches can result in network downtime, data loss, and compromised network integrity.