Cisco 300-425 - Designing Cisco Enterprise Wireless Networks (ENWLSD)

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 collapsing all controllers to a single cluster in a central location, one must consider the availability of channels across different regions. Regulatory domains vary globally, and certain channels allowed in Europe may not be available or legal in other parts of the world. This can affect the consistency of wireless coverage and performance.

https://www.cisco.com/c/en/us/td/docs/wireless/controller/technotes/86/b_Cisco_Wireless_LAN_Controller_Configuration_Best_Practices.html

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

 In a wireless network design where redundancy is required for guest access, setting different priorities for the anchor controllers ensures that one serves as the primary and the other as a backup. Anchor A, being the primary controller, should have a higher priority (lower numerical value), making it the preferred choice for guest WLAN connections. Anchor B, as the secondary or backup controller, should have a lower priority (higher numerical value) so that it is used only if Anchor A fails. This approach provides a failover mechanism for guest access in the DMZ.

For a wireless voice deployment, Cisco recommends that the edge of the cell should have a signal strength of -67 dBm to ensure reliable voice quality and seamless roaming capabilities.

To support VoWLAN services and provide roaming recommendations to supported voice clients without impacting non-VoWLAN clients, the feature that should be enabled on the VoWLAN SSID is 802.11k neighbor lists. This feature allows APs to provide information about neighboring APs that are candidates for roaming, which helps clients make better decisions about when and where to roam. 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.

The command debug mobility handoff enable is used to validate the mobility control packets between Wireless LAN Controllers (WLCs). This command enables debugging of the handoff process, which is critical for ensuring seamless client roaming between controllers. When WLCs are separated by firewalls, it is essential to confirm that mobility control packets can traverse these firewalls without being dropped or rejected. The debug mobility handoff enable command allows network administrators to monitor the handoff process and troubleshoot any issues that may prevent successful client roaming.

Raising the minimum data rate to 24 Mbps will reduce the range at which devices can connect, thereby reducing channel overlap. Using directional antennas can also help limit the coverage area of some APs, which can further reduce channel overlap by focusing the signal in specific directions rather than in a broad coverage pattern. References: Designing Cisco Enterprise Wireless Networks (ENWLSD 300-425)

 The protocol that needs to be allowed between the networks where the controllers are installed is IP Protocol 97, which is used for encapsulating IP within IP, often used in network mobility and IP tunneling.