A study on the end-to-end performance of TCP over ABR at the HFC network using an ATM backbone network

With the increasing requirement for more bandwidth and high-speed networks, the asynchronous transfer mode (ATM) has become the main consideration of many academic and industrial entities. Also, the Internet growth and the convergence of the television with the computer has led cable companies to develop methods of delivering broadband services to residential customers. Cable networks are based on modified LAN (local area network) technologies and the hybrid fiber coax (HFC) network, which accounts for the backbone of most modern cable systems. This paper is a study on the end-to-end performance of TCP over ABR (available bit rate) at the HFC network using an ATM backbone network where the ABR service has a very complicated mechanism. The ABR service mechanism constantly monitors the network switch´s load and feed this information back to the sources. The drawback of the HFC network is that these networks are all based on media sharing. This only presents a problem when the network is under heavy use. Moreover, because of the interference between TCP flow control and ABR flow control, the performance is reduced. In this environment, the 802.14 MAC (media access control) protocol supports the ATM ABR service. But, the MAC contention algorithm of the upstream interferes with the rate control mechanism of ABR. The simulation results show that the traffic of TCP over ABR depend on the sender´s network and the returned RM (resource management) cells´ delay time. In order to increase the performance of TCP, we need more studies on the MAC contention mechanism and TCP traffic controls