Routing Architecture for the Dependable Internet

Routing technologies are discussed in this dissertation with the goal of improving the network availability. The “highly available Internet” is defined as the Internet with functions to forecast and control the network availability. An implementation strategy to approach to the highly available Internet and to the Dependable Internet is described. This dissertation provides a routing simulator called SimRouting to calculate the network availability, an example of oscillation-tolerant OSPF routing protocol, a family of new multipath route calculation algorithms called MARA, and a newmultipath routing architecture called Drouting. The reliability of communication network depends on various components, for example, the reliability of hardware communication devices, the stability of communication protocols and software systems, the availability of sufficient capacity of network resources, and the reliability of network operators. Current research focuses on a specific one of these reliability components. For example, research on fault-tolerant systems targets the reliability of individual communication devices, circuits, and systems. Research on communication protocols targets their stability. Traffic engineering research focuses on the utilization of the network bandwidth capacity. The current Internet is built upon the combinations of these individual reliability research technologies. Combining the existing research on reliability of specific components does not improve the practical reliability of the entire communication network for two reasons: 1) Current research does not cover all reliability components. For example, studies on technologies to prevent software bugs, hardware bugs, and mis-configurations by network operators, are not adequate. 2) For many reliability components, no fallback plan is provided when the responsible technologies fail. If a fault-tolerant system or a stabilizing technology for a communication protocol fails, the communication network may cease to function until it is manually repaired. Consequently, the reliability of overall communication network is not sufficient, and the reliability of the Internet is not high enough for mission-critical communication. Focusing on the routing technologies, this research improves the availability of the entire communication system, as the first step of the reliability research for the Internet. Since the routing technology decides the network path that determines the reliability and the