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

In a Cisco wireless network, when designing for client roaming between access points (APs) that are connected to different controllers, especially in a global enterprise with multiple data centers, it is essential to ensure seamless client mobility. Mobility lists are used in such scenarios to define which controllers are allowed to participate in client roaming. This feature allows the APs connected to controllers within one group (e.g., Group ABC) to recognize and facilitate roaming clients from another group (e.g., Group XYZ). The mobility list is configured on each controller and includes the IP addresses of other controllers that should be considered part of the same mobility domain. When a client roams from an AP on one controller to an AP on another controller, if both controllers are in each other’s mobility list, they will establish a mobility tunnel through which they exchange the client’s context and security credentials. This ensures that the client can roam without re-authentication and maintains session continuity.

 The Cisco Aironet 3800 Series APs support mGig, which allows for higher throughput over existing cabling. However, the maximum cable length that supports 5G operation is limited by the quality of the cable and signal attenuation. Category 5e cabling can support 5G operation up to a length of 130 meters, which is within the acceptable range for maintaining the required signal integrity for 5G speeds.

 In an outdoor mesh network designed to cover sports fields, a 5 GHz, 14-dBi patch antenna is suitable for the RAP for backhaul connectivity. The higher gain and directional nature of a patch antenna help in focusing the signal over longer distances and in specific directions, which is ideal for connecting various points in a large outdoor area5.

https://www.cisco.com/c/en/us/products/collateral/wireless/aironet-antennas-accessories/product_data_sheet09186a008008883b.html

When conducting site surveys for WLAN upgrades to 802.11n, it’s important to consider AP locations that allow for easy access. This facilitates quick maintenance and upgrades, ensuring minimal downtime and disruption to the network. While aesthetics and power availability are also considerations, the primary focus should be on maintaining the network’s performance and reliability.

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.

 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.

For accurate location services, it is recommended that each location-ready AP hears at least four other APs at a signal level of -75 dBm or better. This ensures sufficient signal overlap and triangulation accuracy for reliable client location tracking. References: Cisco’s guidelines on wireless network design for location services.

 LAG-based redundancy is chosen for its ability to provide continuous connectivity as long as one port in the LAG is operational (B), utilize the full bandwidth capacity of all the links in the LAG (E), and allow for the grouping of ports into multiple LAGs for increased redundancy and bandwidth (F). References: CCNP Enterprise Wireless Design ENWLSD 300-425 and Implementation ENWLSI 300-430 Official Cert Guide.