A novel method of link-state update in wavelength-routed networks

Link-state update is a critical component of the routing protocol in wavelength-routed networks. High-frequency updates impose heavy traffic on network control channels as well as excessive burden of electronic processing, while stale link-state information seriously degrades network performance. Therefore, a tradeoff has to be made between control overhead and network blocking probability. This paper proposes a novel link-state update method. By actively regulating the link-state update rate, the proposed method efficiently handles the inherent burstiness of link-state changes without overloading control network with excessive update messages. To improve the blocking performance under limited control bandwidth, it assigns different types of updates with different priorities such that the stale link-state information of more negative impact has a higher chance to be removed. Comprehensive performance evaluations show that the method successfully enforces the control bandwidth quota while achieving much lower blocking probability than existing link-state update methods.