An enterprise network is experiencing poor VoIP call quality, and complaints are coming from multiple departments. No recent changes have been reported. Which approach would be most effective for initially investigating this network-wide issue?
Immediately replace VoIP hardware like phones and PBX systems.
Use a top-to-bottom OSI model approach to check each layer.
Conduct an extensive audit of recent network changes despite reports.
Use a Wi-Fi analyzer solely on the wireless networks.