Pass the Cisco CCNP Enterprise 300-425 Questions and answers with CertsForce

 Devices that can tolerate at most 100 ms of delay when roaming are typically voice devices. Voice applications are sensitive to delays, and ensuring a maximum of 100 ms delay is a common design criterion for a wireless network supporting voice services. References: Designing Cisco Enterprise Wireless Networks (ENWLSD 300-425)

When a client roams between two access points (APs) that are registered to different controllers with interfaces in the same client subnet, the controllers will exchange mobility control messages over UDP port 16666. This is in accordance with the Designing Cisco Enterprise Wireless Networks (ENWLSD) guidelines. The purpose of these messages is to ensure seamless roaming, where the client’s session and authentication state are transferred from one controller to another without requiring re-authentication or re-association by the client. The mobility control messages facilitate the coordinated transfer of the client database entry from the original controller to the new one, maintaining a consistent experience for the user.

When conducting an outdoor bridge site survey, weather and the Fresnel zone are critical criteria to consider. Weather can affect signal propagation and the reliability of the wireless link, while the Fresnel zone relates to the elliptical area around the line-of-sight path between transceivers, which must be clear of obstacles to ensure a strong signal. References: Designing Cisco Enterprise Wireless Networks (ENWLSD 300-425)

 AP groups allow the engineer to apply different policies for APs in the auditorium versus those in the hallway. RRM (Radio Resource Management) can dynamically adjust the TX power and channel settings to optimize the wireless coverage and capacity.

When conducting a Layer 2 site survey, it is recommended to match the survey to the worst client available. This ensures that the wireless network is designed to provide adequate coverage and performance even for the clients with the poorest capabilities, thereby ensuring a consistent user experience for all devices2.

https://www.cisco.com/c/en/us/support/docs/wireless/5500-series-wireless-controllers/116057-site-survey-guidelines-wlan-00.html

Voice services on a wireless network require a strong and stable signal, as well as low interference and retransmission rates. An RSSI (Received Signal Strength Indicator) of at least -67 dBm is considered the minimum for acceptable voice quality, and -65 dBm is even better, providing a buffer for signal fluctuation. A noise floor of -87 dBm would be too high and could interfere with signal clarity. Retransmission rates should be kept as low as possible; 15% or below is a good target to ensure efficient communication.

References: CCNP Enterprise Wireless Design ENWLSD 300-425 and Implementation ENWLSI 300-430 Official Cert Guide

When performing a Layer 1 survey using Metageek Chanalyzer, the Cisco CleanAIR AP should be configured in Monitor mode. This mode allows the AP to scan the environment for interference without serving clients.

To mitigate increased co-channel interference and retransmissions after adding an AP, Transmit Power Control (TPC) and Dynamic Channel Assignment (DCA) can be effective. TPC adjusts AP transmit power based on real-time analysis of the wireless environment, reducing interference by lowering power where necessary. DCA dynamically changes channel assignments based on current RF conditions to optimize performance and minimize interference.

The behavior of guest client sessions in the US being anchored to the WLCs in Europe despite the presence of a local anchor WLC can be explained by the failure and subsequent recovery of the US anchor WLC. During the failure, the guest sessions would have been transferred to the European WLCs. After recovery, if the priority settings were not correctly restored or if the system did not automatically revert back to the local anchor, the sessions would remain anchored to the European WLCs3.

References: CCNP Enterprise Wireless Design ENWLSD 300-425 and Implementation ENWLSI 300-430 Official Cert Guide Premium Edition and Practice.

The data path issue between the Cisco Catalyst 9800-CL and AireOS 5520, despite an active control path, is likely due to encrypted mobility being enabled on the AireOS 5520. Encrypted mobility requires both peers to have a matching configuration for encryption, which includes proper certificates and shared secrets. If there’s a mismatch, the control path may be established, but the data path can fail due to the inability to establish an encrypted tunnel.