Unlike traditional phone calls over public switched telephone
networks (PSTN), VoIP calls do not traverse dedicated
networks and are thus subject to uncontrolled delay,
jitter, and losses. Even in an enterprise environment, where
network infrastructures are normally well-provisioned and
managed, VoIP calls can still experience significant quality
degradation [2]. This is because an increasing number of users
are connecting through WiFi links, which have unpredictable
delay, jitter, and loss behavior. Indeed, the large-scale study