Flow management aspects for multi-layer QoS provisioning in IP-over-WDM networks

All-optical switching networks based on Dense Wavelength Division Multiplexing (DWDM) technology have been proposed as backbone networks for the next generation Internet to meet increasing bandwidth requirements. Currently, there are three all-optical switching technologies in DWDM, namely, Optical Circuit Switching (OCS), Optical Packet Switching (OPS) and Optical Burst Switching (OBS). Among them, OBS is a promising solution for the near future, since it combines the advantages of OCS and OPS. In addition to bandwidth demands, the Internet is also challenged by Quality of Service (QoS) issues. Multi-Protocol Label Switching (MPLS) is a standard QoS provisioning architecture for layered IP networks. It provides flow level QoS guarantees for IP traffic. Flow management based on the MPLS architecture is an important research area for QoS provisioning in IP-over-WDM networks. Currently, the MPLS solution for OCS and OPS networks has been developed. However, the integration of MPLS and OBS is still an open issue.; This thesis investigates several flow management mechanisms for QoS provisioning in MPLS-based IP-over-WDM networks, in both the packet switching IP layer and the burst switching all-optical transport layer. There are three major contribution areas in the thesis. Firstly, in the IP layer, a new backward connection preemption mechanism and two distributed label merging algorithms are proposed. The backward preemption mechanism saves preemption costs by finding and removing redundant preemptions during the MPLS signaling process. Label merging algorithms reduce the expense of label maintenance and label searching by merging point-to-point Label Switched Paths (LSPs) into multipoint-to-point LSP trees.; Secondly, a novel hybrid OBS architecture is proposed. It enables the construction of no loss guaranteed burst delivery channels (called burst LSPs) using MPLS signaling protocols for periodically scheduled burst flows. The standard MPLS based QoS provisioning architecture can be realized in OBS networks.; Thirdly, channel scheduling and burst flow routing algorithms are proposed for the hybrid OBS architecture. Hybrid channel scheduling avoids inter-class wavelength contention between periodically scheduled bursts and best effort bursts. Three dynamic weight functions for shortest path routing are proposed and compared. They estimate the flow blocking rate based on wavelength utilization to balance load on the network.