The document discusses maximizing the quality of monitoring (QoM) in multi-channel wireless infrastructure networks using distributed wireless sniffers. It defines QoM as the expected number of active users monitored and investigates assigning sniffers to channels to maximize this. Two capture models are considered - user-centric which distinguishes users, and sniffer-centric using only channel activity data. Maximizing QoM is NP-hard for user-centric but a constant approximation is possible. For sniffer-centric, stochastic inference transforms it to user-centric to apply approximation algorithms. Evaluation uses synthetic and real-world traces showing the effectiveness of proposed schemes.