You recently deployed an 802.11ac wireless network that contains Cisco Unified Wireless IP Phones 7925G. Users report that the phones intermittently lose connectivity. Which troubleshooting step is th

Reviewing Cisco WLC log files for authentication failures primarily addresses Layer 2 and Layer 3 issues, which are higher in the OSI model than the physical layer.

Using a packet sniffer to capture 802.22 frames is incorrect as 802.22 is for Wireless Regional Area Networks, not Wi-Fi (802.11), and capturing frames would be a Layer 2 troubleshooting step.

According to the bottom-up troubleshooting methodology, the first step is to examine the physical layer (Layer 1). For intermittent wireless connectivity issues, performing an RF site survey directly investigates the physical medium by checking signal strength, noise, interference, and potential coverage gaps, which are common causes of such problems in a wireless network.

Comparing Cisco IOS versions of the controller and phones is a configuration or compatibility check, which falls under higher layers (Layer 7 or management plane) and is not a Layer 1 troubleshooting step.