An integrated approach to scalable and efficient QoS routing, QoS monitoring, and QoS restoration

The present best-effort Internet architecture is not suitable for soft real-time, multimedia applications, which are characterized by high speed continuous traffic and have constraints on parameters such as packet delay and connection bandwidth. These constraints are typically referred to as Quality-of-Service (QoS) requirements. An important aspect of providing QoS to a multimedia application is QoS routing. QoS routing consists of determining a path through the network with adequate resources to satisfy the QoS requirements of a connection, while simultaneously achieving global efficiency in network resource utilization. The required level of resources are then reserved along this path for the entire lifetime of the connection. Despite resource reservation, the connection may still experience QoS degradation due to the weakening or failure of one or more nodes/links along the path. QoS monitoring is concerned with monitoring an established connection so that QoS degradation can be predicted prior to occurrence, or at least detected as soon as possible after it has occurred. In this case, the connection should be restored quickly to an alternate suitable path, and this is referred to as QoS restoration. Most of the QoS routing, QoS monitoring, and QoS restoration techniques in the literature are designed primarily for intra domain connections. The associated overheads become excessive when these techniques are used in the context of inter-domain connections. Further, existing research on these three aspects of QoS has progressed independently, leading to inconsistent solutions, and this causes additional inefficiencies in the utilization of resources. In this dissertation we seek to develop comprehensive, scalable and efficient schemes to provide solutions to the problems of QoS routing, QoS monitoring and QoS restoration in case of inter domain connections. The QoS routing scheme is designed with an eye towards facilitating QoS monitoring and restoration, and the QoS monitoring and restoration schemes are designed to benefit from the support provided by the QoS routing scheme. By considering routing, monitoring and restoration in an integrated manner during the design process, the overheads are considerably mitigated. Extensive analysis and simulations have been conducted to evaluate the proposed schemes and compare them to prevalent techniques in the literature. The results demonstrate that the proposed schemes provide improved performance with lower overheads.