A hierarchical HFC network with QoS guaranteed traffic policy

The rapid growing of the Internet makes multimedia and broadband services closer to the users. For people at home, two typical networks are available to access the Internet: telephone network and CATV network. This paper presents a hierarchical tree-based structure for the hybrid fiber-cable (HFC) network where the traditional HFC network is partitioned into segments. Each segment is coordinated by a central traffic controller (CTC). A reservation-based traffic policy is also proposed for the CTC to schedule the data transmissions within the segment to provide guaranteed QoS, such as constant bit rate (CBR) service and variable bit rate (VBR) service. The CTC also furnishes the bridging function so that local traffic within the controlled segment is filtered to save the network bandwidth. Based on the segmentation concept and filtering function, the bandwidth can be reused efficiently and the system performance is improved significantly. Simulation results indicate that the proposed hierarchical HFC network performs much better than the traditional HFC network in terms of delay, delay jitter and channel utilization. Through the proposed traffic policy, the hierarchical HFC network also offers guaranteed QoS for the users.