Availability Evaluation of Hybrid Wireless Optical Broadband Access Networks

The hybrid wireless-optical broadband access network (WOBAN) architecture provides a new and promising architecture for access networks by combining the beneficial properties of wireless and optical technologies. Thus it can achieve low deployment costs (as no cable infrastructure is necessary for the last mile) and provide a mobile yet economically viable end-user access. However, the integration of these technologies (optical and wireless) also has its challenges: While optical links have high availabilities (especially with modern protection techniques), the performance of wireless links depends on a variety of external parameters, which in many cases can be only described statistically. In this work, we evaluate the availability performance of a WOBAN in different demand scenarios and study the influence of various routing strategies (shortest paths with different link metrics, specialised routing algorithms for a WOBAN and multi-path routing). Our results show that we can significantly improve availability for end-users by using shortest path routing with link unavailability as the link cost metric. Using multi-path routing, further gains can be achieved.