Modifications to and performance evaluation of output scheduling in 3LIHON nodes

Optical networks became very important in the latest years, thanks to their high traffic capacity, because of the continuous growth of total exchanged data and the request of real-time communication. Since they have (relatively) long adaptation times, this technology is not inherently the most suitable to carry bursty traffic like the current one. Hybrid networks try to get the best from optical circuit switching and optical packet switching. This work is focused on an hybrid network architecture called 3LIHON (3-Level Integrated Hybrid Optical Network). It has three different quality of service (QoS) levels, in order to meet different requirements: • Guaranteed Service Type (GST): resembling an optical circuit switched service, it does not allow data loss. • Statistically Multiplexed Real Time (SM/RT): resembling an optical packet switched service, it ensures none or very small delay inside the network, it allows a low data loss ratio and bandwidth contention. • Statistically Multiplexed Best Effort (SM/BE): resembling an optical packet switched service with very small overall packet loss but no guaranteed delay inside the nodes. In a 3LIHON node, SM/BE traffic interrupted by packets with higher priority is dropped. This means that time and resources spent sending the SM/BE packet until the interruption are wasted. In this work we try to avoid this behaviour, by implementing and