Advanced link and transport control protocols for broadband optical access networks

The objective of this dissertation is to improve the service quality of broadband optical access networks by developing advanced link- and transport- layer protocols. Access networks connect business and residential premises to metropolitan area networks or wide area networks. Current access technologies represent a significant bottleneck in bandwidth and service quality between a high-speed residential/enterprise network and a largely overbuilt core backbone network. Although it is believed that passive optical network (PON) will be the most promising solution to provide truly broadband connections to end users, a suit of protocols are required to provide dedicated bandwidth, controlled delay and jitter, and preferable packet loss characteristics, for quadra play applications including data, voice, video, and interactive multimedia games. This dissertation studies three key techniques for improving quality of service (QoS) performance of broadband access networks, including transport protocol for broadband networks, media access control (MAC) protocol for PON, and delta compression for fast content download.; In this dissertation, we design a new reservation MAC scheme that arbitrates upstream transmission, prevents collisions, and varies bandwidth according to demand and priority. The new access scheme exploits both WDM and TDM to cater for both light and heavy bandwidth requirements. We analyzed, evaluated, and simulated the performance and practicality of the proposed scheme.; Next, we introduce delta compression algorithms as an efficient method for fast content download. We present a theoretical framework for delta compression based on information theory and Markov models, including insights into the compression bounds. We also simulated and implemented a generic delta compression scheme and demonstrated its real-time and non real-time performance.; In the third part of this dissertation, we enhance the transport performance of Ethernet services by addressing the throughput optimization issue at the edge of the network. The performance of TCP over SLA driven Ethernet services is not adequate, because the mechanisms of TCP are designed for best effort networks and cannot utilize the reserved bandwidth efficiently. In this research, an SLA-aware transport protocol is proposed to increase the end-to-end throughput for Ethernet services.; To reduce the impact of random loss to application layer throughput, a resilient transport control scheme dealing with random error is proposed for Ethernet services. Transport layer congestion control is stated as a hypothesis test process making decisions through the ACK feedbacks. It is shown that traditional TCP adopts a very simple decision rule making decisions based on only a single sample. A novel resilient congestion control scheme is proposed with a better decision rule using multiple samples. The new method increases throughput significantly by keeping false-alarm probability under control and adjusting congesting window adaptively.