Quantum packet for integrated services data network : the third generation ISDN

Abstract

In the last century, two generations of Integrated Services Digital Network (ISDN) have been developed, which are referred to as ISDN1 and ISDN2, respectively. As ISDN1 is based on a synchronous architecture, it cannot handle broadband traffic effectively, hi ISDN2, Asynchronous Transfer Mode (ATM) is introduced to provide connection-oriented services by using fixed size packets called cells. This facilitates the implementation of high-speed switches and provides better priority management. However ISDN2 is mainly designed for supporting connection-oriented traffic so it is less effective to support connectionless data traffic, active network technologies, and multicast services. In our view, ATM, the Internet and active networks will be combined to establish the framework for ISDN3 - the next generation of ISDN. In ISDN3, a connectionless base network is adopted to provide both connection-oriented and connectionless services over the same network. With the aim of combining the advantages of cells and datagrams, a novel quantum packet method is proposed to support different types of traffic. Different network functions are integrated in a traffic-forwarding device called the Forwarding EnginE (FEE). To support ISDN3, the aim of this thesis is to investigate the quantum packet method for carrying data traffic effectively over ISDN3. Basically, a quantum packet comprises one or more 53-byte quanta, which is created by a "quantumization" process. This packetization process can be viewed as an extended ATM Adaptation Layer (AAL) process. Whereas connection-oriented traffic is supported by fixed-size quantum packets each with one quantum to emulate circuit switching, connectionless traffic, such as Internet Protocol (IP) packets and active packets, is supported by variable-size quantum packets with multiple quanta. Our aim is to provide datagram-like services while enabling cell-based multiplexing. Last but not least, the quantum packet method gives a flexible and extensible framework while maintaining backward compatibility with ATM. In this thesis, we discuss the design of the quantum packet method, including its format, the "quantumization" process, and the support for different types of traffic. We also present an analytical model to investigate the consumption of network resources when quantum packets are employed to transport loss-sensitive traffic by using three different approaches. In particular, close form mathematical expressions are obtained for some cases. To study the system performance when connection-oriented and connectionless quantum packets are multiplexed over a link, we formulate a Markov model to analyze the nodal transfer delay and the packet loss ratio for three multiplexing schemes. One type of quantum packet is active and one of its applications is to provide active routing services. To support active routing in ISDN3, we formulate a Markov decision model to determine a threshold-based routing policy. Analytical results are presented to show that the proposed policy can give better performance than several other approaches.