Protection

The central hub of our AWG based single-hop network forms a single point of failure. In this chapter, we address the survivability of our AWG based network. There are different types of network failures comprising node, fiber, and hub failure. While node and fiber failures have only a local effect in our network, the central AWG represents a single point of failure. That is, if the AWG goes down the network connectivity is entirely lost. In the following, we concentrate on the protection of this single point of failure. Under normal operation the proposed protection scheme not only avoids the single point of failure but also enables spatial wavelength reuse at all AWG ports at any given time and allows for transmitting control at significantly higher line rates by replacing the broadband light source with a laser diode. In the following, we highlight the rationale behind the presented protection scheme and show some illustrative results. For detailed information on the analytical performance evaluation, additional results, and an in—depth discussion the interested reader is referred to [FMR03].