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

The mesh backhaul link uses Advanced Encryption Standard (AES) for encryption. AES is a robust encryption standard that is widely used in various security protocols, including WPA2 and WPA3, to provide a high level of security for wireless communications. It ensures that the data transmitted over the mesh backhaul link is protected against unauthorized access and eavesdropping.

The issue where APs failed over to the tertiary controller instead of the secondary controller during a controller failure is likely due to the secondary controller being at capacity. When a controller reaches its maximum capacity, it cannot accept any additional APs, causing them to failover to the next available controller in the high availability configuration.

 Cisco workgroup bridges typically support up to 8 wired clients. With 42 users, each having a computer and a VoIP phone, that’s a total of 84 devices. To connect all devices while keeping costs at a minimum, the company would need 6 APs (as 7 x 12 = 84), with each AP supporting 14 devices (7 computers and 7 VoIP phones).

So, each AP will have 25 clients. Minimum 4 APs are sufficient.

Devices that only support 2.4 GHz can increase congestion on this frequency band, especially in environments where multiple devices are present. This is because the 2.4 GHz band has fewer non-overlapping channels compared to 5 GHz, leading to more interference and potential performance issues.

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.

When Client A roams from AP1 on WLC1 to AP2 on WLC2 across different subnets, this is considered a Layer 3 roam. Unlike Layer 2 roaming where the client’s database entry moves with them, in Layer 3 roaming, the client’s database entry is copied to the new controller (WLC2). This ensures continuity of service as Client A transitions between access points managed by different wireless LAN controllers. References := (CCNP Enterprise Wireless Design ENWLSD 300-425 and Implementation ENWLSI 300-430 Official Cert Guide Premium Edition and Practice)

 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)

 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.