A hybrid MAC protocol for HFC networks

Abstract

This paper presents a hybrid medium access control (MAC) protocol for hybrid fiber-coaxial (HFC) networks, which behaves in a a contention and reservation (CR) fashion under light load and in a time division multiple access (TDMA) mode under heavy load. The contention based protocol suffers low throughput under heavy load due to the high contended probability and the TDMA exhibits a long access delay under a light load. To overcome the shortcomings of these two mechanisms, a hybrid CR and TDMA MAC protocol, denoted as HCR&TP, is proposed. The headend is responsible for switching between CR and TDMA according to the system's traffic load. Furthermore, the HCR&TP supports both synchronous transfer mode (STM) and asynchronous transfer mode (ATM) services. The simulation results indicate that the HCR&TP achieves a high throughput and short access delay under any offered load.