QoS Provisioning Method for Downstream VoIP Service Flows in HFC Networks

Conventional researches on QoS provisioning in HFC networks have focused mainly on the upstream channels. However, due to changing network usage patterns, the provisioned capacity for downstream service flows is no longer sufficient. To provide QoS for downstream VoIP service flows in HFC networks, an adaptive committed information rate allocation algorithm is proposed. Given the maximum sustained traffic rate and the minimum reserved rate for each service flow, it allocates service rates to VoIP and best effort connections adaptively for possible cases of network congestion. The proposed algorithm is directly tested in a commercial HFC network, and it is shown to reduce packet losses, jitter, and delay in the HFC network, which results in stable VoIP service quality even in network congestion¹.