300-425 Practice Exam Questions with Answers Designing Cisco Enterprise Wireless Networks (ENWLSD) Certification

In a mobility group, multiple controllers should be configured with the same virtual IP address to ensure proper roaming. This virtual IP address is used by wireless clients during the roaming process to facilitate seamless mobility between controllers.

FlexConnect mode is ideal for branch offices and remote locations where it’s necessary to minimize wireless traffic tunneled back to the Wireless LAN Controller (WLC). In FlexConnect mode, APs can perform client authentication locally and bridge traffic onto the local network. References: CCNP Enterprise Wireless Design ENWLSD 300-425 and Implementation ENWLSI 300-430 Official Cert Guide.

 The connectivity of 802.11a, which operates in the 5 GHz band, is reduced in X-ray rooms primarily due to the increased signal attenuation caused by the lead and other dense materials used in the construction of these rooms to shield against X-ray radiation. These materials effectively block or weaken the radio signals used for wireless communication

portable X-ray machines, sending high-resolution images, sometimes in real time, echography machines, and electrocardiography [ECG] machines). These devices may also use the same spectrum as Wi-Fi but with other protocols and, therefore, become sources of interference for your system.

 When performing a site survey of a large outdoor area, a site survey tool with a GPS module is ideal. The GPS module allows for precise location tracking, which is essential for mapping signal coverage over a large area. This tool can help complete the survey efficiently by automatically recording the location of signal measurements

 When configuring Cisco Prime Infrastructure, to represent the impact of a thick glass wall with an attenuation of 2dB on the RF signal, the obstacle that should be placed in the map editor is glass. This is because the material-specific attenuation values are used to model the RF signal’s behavior as it passes through different types of obstacles, and the thick glass wall’s impact is best represented by the glass obstacle in the map editor.

Mobility domains and mobility groups are concepts used in Cisco wireless networking to manage client roaming and controller interaction. When Wireless LAN Controllers (WLCs) are part of the same mobility domain, they share a common database, allowing them to communicate and facilitate seamless client roaming. A mobility group is a subset of this domain, where specific WLCs work together more closely to share client context and security credentials. This ensures that when a client roams from one access point (AP) to another across different controllers, the authentication and security context are maintained, allowing for a seamless transition without the need to re-authenticate. The mobility group also manages AP fail-over between controllers, ensuring clients can maintain their connections even if their current AP fails or becomes unreachable.

https://www.cisco.com/c/en/us/td/docs/wireless/controller/8-0/configuration-guide/b_cg80/b_cg80_chapter_010011.html

The IEEE 802.11r protocol, also known as Fast BSS Transition (FT), is designed to support real-time applications by enabling faster roaming between APs. This protocol reduces the number of packets exchanged during the reauthentication process when a client moves from one AP to another, thus ensuring a more seamless transition and maintaining the quality of service required by real-time applications such as voice and video conferencing. References: Designing Cisco Enterprise Wireless Networks (ENWLSD 300-425)

In a high availability setup with Cisco 5508 Wireless LAN Controllers, the standby controller can be accessed via the console connection and the service port interface. The console provides direct access, while the service port interface allows for network-based access to the standby unit for management purposes.

When designing a wireless network for diverse clients, it’s crucial to ensure that the network will be reliable for all users. Therefore, surveys should be conducted with the client that has the worst RF characteristics, as indicated in option D. This approach ensures that the network is designed to support even the weakest client, thereby providing a consistent experience for all users. 

https://documentation.meraki.com/MR/WiFi_Basics_and_Best_Practices/Conducting_Site_Surveys_with_MR_Access_Points

Creating a mobility group requires that all Wireless LAN Controllers (WLCs) share the same mobility group name. This allows them to recognize each other as peers and participate in client mobility events. The WLCs must be defined as peers in each other’s static mobility members list to facilitate inter-controller communication and roaming.

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.

To reduce full authentication requests and optimize roaming, enabling Cisco Centralized Key Management (CCKM) on the voice SSID is effective. CCKM allows for fast re-authentication during roaming, which is beneficial for voice applications. Adding APs to a FlexConnect group helps manage APs in remote branches more efficiently.

To connect multiple wired devices over a workgroup bridge using an autonomous AP, a router is needed to manage the IP addresses and route traffic between the wired devices and the wireless network. The router will act as a gateway for the wired devices, allowing them to communicate with the WLAN. References: Cisco autonomous AP configuration guides and workgroup bridge deployment scenarios.

 To ensure that the most critical APs at remote sites remain functional in the event of a failure, the Global AP Failover Priority feature can be used. By setting the priority of the most important APs to “critical”, these APs will be given precedence over others during a failover scenario. This allows the engineer to prioritize which APs should remain online without impacting the main site’s APs, which are set to a “high” priority.

 The Cisco 5520 WLC v8.3 requires a base license to use OfficeExtend AP functionality, which allows remote workers to have the same wireless connectivity as they would in an office environment.

By segmenting the VLAN into smaller subnets and assigning them by location, an engineer can use interface groups. This allows for efficient management of network resources and ensures that clients are connected to the closest subnet, reducing latency and improving performance.

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

 To optimize RF performance across different buildings and user densities: C. Configure AP groups for each area type - This allows for customized settings for APs serving different areas. D. Configure RF profiles for each area type - RF profiles enable the customization of RF parameters to suit the specific needs of each building or area type.

References: The official Cisco ENWLSD 300-425 certification guide will provide more information on RF optimization strategies.

https://www.cisco.com/c/en/us/td/docs/wireless/controller/8-10/config-guide/b_cg810/configuring_ap_groups.html

When the mobility tunnel is not operational for the data path, it is essential to validate the network’s firewall settings. Firewall port 16666 must be open to allow mobility control messages to pass through, and firewall IP protocol 97 (EtherIP) must be permitted to enable the encapsulation of IP within IP, which is necessary for the data path of the mobility tunnel. Ensuring these firewall settings are correctly configured is critical for facilitating inter-controller roaming and operational mobility tunnels.

https://www.cisco.com/c/en/us/td/docs/wireless/controller/7-4/configuration/guides/consolidated/b_cg74_CONSOLIDATED/b_cg74_CONSOLIDATED_chapter_010100001.html

EoIP (Ethernet over IP) is used for communication between controllers in a guest anchor setup, allowing for seamless roaming. Inter-Controller Roaming Mechanism (IRCM) support is necessary for the controllers to facilitate roaming across different wireless LAN controllers.

Guest anchoring requires mobility tunnels to be established between the foreign and anchor WLCs. For these tunnels to function, the firewall must allow specific ports for communication. UDP port 16666 is the port used for mobility traffic in Cisco wireless networks, and if it is not allowed through the firewall, MPING and mobility tunnels will fail. References: CCNP Enterprise Wireless Design ENWLSD 300-425 and Implementation ENWLSI 300-430 Official Cert Guide Premium Edition and Practice

For handheld mobile scanners processing credit card payments, security and seamless roaming are critical. The 802.11w standard, also known as Protected Management Frames (PMF), provides enhanced security that helps prevent disconnections and issues when roaming between access points. Incorporating 802.11w in the design ensures that the scanners maintain a secure and consistent connection while moving throughout the environment. References: CCNP Enterprise Wireless Design ENWLSD 300-425 and Implementation ENWLSI 300-430 Official Cert Guide Premium Edition and Practice

 A fully measured wireless survey requires tools that support the active functioning of the network and allow for physical access to install and measure equipment. A PoE (Power over Ethernet) battery is necessary to power the access point during the survey. The access point itself is essential for broadcasting the signal. A ladder is needed to reach high places for proper access point placement and to measure coverage areas effectively.

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

https://www.cisco.com/c/en/us/td/docs/wireless/technology/mesh/81/design/guide/b_mesh_81/Site_Preparation_and_Planning.html

When configuring high availability on an access point, a network engineer can configure a maximum of two controllers. One serves as the primary controller, and the other serves as the secondary controller.

Link Aggregation Group (LAG) allows multiple physical ports to be combined into a single logical channel. In the scenario where only one Cisco 9800-40 WLC is available and high availability is required, LAG can be used to manage port redundancy and perform load balancing between APs transparently. This ensures that if one cable fails, the others can continue to carry the traffic without any perceived downtime

When identifying network requirements, it’s important to consider the number of wireless devices that will need access to ensure sufficient capacity and coverage. The business type can influence the types of applications and services that will be used, which in turn affects the network design.

 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.

Access points can be assigned different failover priorities to determine the order in which they will failover in the event of a primary controller failure. An access point with priority 1 is given the highest priority level and is considered critical. This means it will failover before other access points with lower priorities, ensuring that the most critical areas remain covered.

For a point-to-multipoint mesh network site survey, configuring the Rx power and Tx power is essential. Rx power will determine the sensitivity of the AP to incoming signals, which is crucial for understanding the reach of each mesh point. Tx power settings will influence the strength of the signals transmitted from the AP, affecting the network’s overall coverage. References: Designing Cisco Enterprise Wireless Networks (ENWLSD 300-425)

 To predict the number of APs needed to support approximately 300 wireless devices on a new floor with an 802.11ac network, the Demand Settings in the Cisco Prime Infrastructure Planning Tool must be adjusted. This setting allows the planner to specify client density and throughput requirements, which are crucial for determining the correct number of APs.

In high-density environments, such as stadiums or auditoriums, APs are often mounted under the seats to provide a controlled cell size with attenuation. This placement helps to manage the RF environment by providing attenuation of 6 dB to 20 dB, which can reduce co-channel interference and improve the user experience by ensuring a strong signal and minimizing noise from other cells.

 Changing the TPC Power Threshold to -65 dBm would generally result in a decrease in the transmit power of APs to maintain a smaller cell size. This helps in reducing interference and improving overall network performance. A lower threshold means the APs reduce their power to ensure the signal does not exceed -65 dBm, leading to decreased signal strength at the client side.

 The concern with existing gigabit uplinked switches providing 802.3at is the output power limitation. 802.11ac Wave 2 APs may require more power than what 802.3at can deliver, especially for features like Multi-User Multiple Input Multiple Output (MU-MIMO). References: CCNP Enterprise Wireless Design ENWLSD 300-425 and Implementation ENWLSI 300-430 Official Cert Guide.

 For optimal Voice over WLAN (VoWLAN) design, a higher data rate is preferred to ensure quality of service and reliability. -67 dBm is a commonly recommended signal level for VoWLAN, and 802.11an, which operates in the 5 GHz band, is capable of supporting higher data rates compared to 802.11bgn, which operates in the 2.4 GHz band. The 5 GHz band is less crowded and prone to interference, making it suitable for high-speed data and voice applications.

The WPlus license is suitable for environments using OfficeExtend Access Points (OEAP), which allows employees to work from home with a seamless connection to the corporate wireless network. The WPlus license enables features such as advanced security and increased scalability for remote workers. References: CCNP Enterprise Wireless Design ENWLSD 300-425 and Implementation ENWLSI 300-430 Official Cert Guide.

 The Cisco 8540 Wireless Controller is designed for large enterprise and high-density environments. It has the capacity to manage up to 6000 access points, making it suitable for a multicampus architecture that needs to accommodate 4500 access points. Its high availability features ensure that all access points can be supported on one controller setup with minimal downtime.

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

FlexConnect APs must be in a FlexConnect group to support 802.11r Fast Transition (FT). This grouping allows for local authentication and key management, which are necessary for fast roaming methods that improve voice quality and wireless IP phone performance during roaming.

References: The official Cisco FlexConnect configuration guide 

 In a high-availability configuration, orphaned APs will join the controller with the lowest percentage of associated Access Points (APs) per license capacity by default. This ensures a balanced distribution of APs across the controllers in the mobility group, optimizing resource utilization and network performance. References: Designing Cisco Enterprise Wireless Networks (ENWLSD 300-425)

The ‘tracert’ command is used to test connectivity between members of a mobility group by tracing the path that mobility control packets take over the network. This command helps identify any potential issues with the route that the packets are taking, which could affect the ability of guests to connect to the anchor controller in the DMZ. References := (CCNP Enterprise Wireless Design ENWLSD 300-425 and Implementation ENWLSI 300-430 Official Cert Guide Premium Edition and Practice)

 The decision to avoid installing APs directly in offices is likely due to transmit power considerations. Placing APs within offices could lead to excessive coverage for small areas, causing interference with other APs and reducing overall network performance. By placing them in common areas like corridors, engineers can ensure more uniform coverage across larger spaces while managing transmit power more effectively for optimal performance.

References:

• CCNP Enterprise Wireless Design ENWLSD 300-425 Official Cert Guide

https://www.cisco.com/en/US/docs/solutions/Enterprise/Mobility/emob30dg/RFDesign.html#wp1000551

Quality of Service (QoS) is essential for prioritizing cloud services like email and real-time communication. It helps in managing bandwidth allocation and ensuring that critical applications receive the necessary resources for optimal performance.

https://community.cisco.com/t5/wireless-mobility-documents/what-is-cckm-and-how-does-it-affect-fast-and-secure-roaming/ta-p/3130421

Mobility domains and mobility groups are concepts used in wireless networking to manage client roaming and security contexts. When Wireless LAN Controllers (WLCs) are in the same mobility domain, they can communicate with each other, allowing clients to roam seamlessly between APs managed by different controllers. Mobility groups further refine this by constraining the distribution of a client’s security context, which includes authentication and encryption keys, and by managing AP failover between controllers. This ensures that a client can maintain a secure and stable connection as they move throughout the network.

References: Designing Cisco Enterprise Wireless Networks (ENWLSD) 300-425 Official Cert Guide

The survey model described is used for location services, VoIP, data, and video. The placement of APs on exterior walls, building corners, and major turns helps ensure consistent coverage and signal strength for a variety of applications, including precise location tracking and high-quality voice and video communications. References: Designing Cisco Enterprise Wireless Networks (ENWLSD 300-425)

Setting AP fallback to disabled will prevent the AP from moving back to its defined Cisco WLCs automatically after failing over to an undefined controller. This allows manual intervention to determine when the AP should revert to its primary controller.

 In a Layer 1 passive wireless site survey, the chart that indicates the ratio of interference present during the duration of the capture in the 2.4 GHz spectrum is typically a Duty Cycle chart or an Interference chart. These charts display the percentage of time that energy, possibly from interfering sources, is present on a channel. The correct answer would show fluctuations in signal levels over time, highlighting periods where interference might be affecting the channel’s clarity.

In a global mesh deployment, using redundant controllers in the least restrictive regulatory domain ensures the highest number of channels available for backhaul. This design accommodates the varying regulatory constraints of different regions by adhering to the domain with the most lenient channel availability.

For Cisco Wireless LAN Controllers (WLCs) to operate in High Availability (HA) with Stateful Switch Over (SSO), they must be connected through a Redundancy Port (RP). This dedicated port is used for synchronization of stateful information and ensuring seamless failover without service interruption.

 The issue described is indicative of a hidden node problem, where MAP-1 and MAP-3 cannot hear each other’s transmissions but can both communicate with RAP-2. This leads to frame collisions as both MAPs may attempt to transmit at the same time, unaware of the other’s actions. The design needs to address this by implementing mechanisms such as RTS/CTS or adjusting the placement of the APs to avoid this issue.

https://www.cisco.com/en/US/docs/solutions/Enterprise/Mobility/emob30dg/WiMesh.pdf

To support a high density of mobile devices and bond channels in groups of two, the channel width for 802.11a should be set to 40 MHz. Setting the data rates to 24 MB and Mandatory ensures that only APs can send 802.11 management frames at this rate, which helps in managing the airtime fairness. References: CCNP Enterprise Wireless Design ENWLSD 300-425 and Implementation ENWLSI 300-430 Official Cert Guide.

The IEEE 802.11k protocol is designed to enable radio resource measurement and neighbor list radio management packets. This protocol allows wireless devices to better understand their radio environment, which in turn supports real-time applications over wireless by enabling devices to make quicker and more informed decisions about roaming