A HIERARCHICAL HFC NETWORK WITH QOS GUARANTEED TRAFFIC POLICY

The rapid growing of Internet makes the multimedia and broadband servi ces more and more close to the users. For people at home, two typical networks are available to access the Internet: telephone network and C ATV network. This paper presents a hierarchical tree-based structure f or the Hybrid Fiber-Cable (HFC) network where the traditional HFC netw ork is partitioned into segments. Each segment is coordinated by a cen tral traffic controller (CTC). A reservation-based traffic policy is a lso proposed for the CTC to schedule the data transmissions within the segment to provide guaranteed QoS, such as constant bit rate (CBR) se rvice 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 c oncept and filtering function, the bandwidth can be reused efficiently and the system performance is improved significantly. Simulation resu lts indicate that the proposed hierarchical HFC network performs much better than the traditional HFC network in terms of delay, delay jitte r and channel utilization. Through the proposed traffic policy, the hi erarchical HFC network also offers guaranteed QoS for the users.