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 Cisco Spectrum Expert is a tool designed to identify and analyze non-Wi-Fi interference sources. During a post-deployment site survey, it can be used to detect interference from various devices such as cordless phones, Bluetooth devices, microwave ovens, and more. This tool provides a visual representation of the RF environment, allowing engineers to pinpoint the exact source of interference and take appropriate measures to mitigate its impact on the wireless network.

References := Designing Cisco Enterprise Wireless Networks (ENWLSD)

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.

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.

 Frequent disconnections may occur if the RSSI threshold set for optimized roaming is too high, causing clients to attempt roaming too late. Disabling optimized roaming and enabling 802.11v support allows for better client steering by the AP, as 802.11v includes the BSS Transition Management feature, which guides clients to a better AP based on the network’s conditions.

To address the sticky client problem, setting an RSSI (Received Signal Strength Indicator) threshold can help. This configuration will prompt clients to roam to a better AP when their signal strength falls below the set threshold, thus enhancing the roaming experience and ensuring clients are connected to the AP with the strongest signal available.