Different strategies for dynamic multicast traffic protection in elastic optical networks

Growing popularity of content-oriented services is a significant trend observed recently in communication networks. Due to large volumes of traffic related to these services, the network operators search for new solutions that allow to deliver content to end users in a cost-effective manner. Elastic optical network (EON) is a relatively novel solution for optical networks. The main advantages of EONs compared to traditional wavelength division multiplexing (WDM) optical networks are more efficient use of spectrum resources and support of flexible modulation format conversion. Moreover, there is a strong focus on multicasting, which is perceived as a much better approach for content delivery compared to unicast transmissions. In this paper we concentrate on dynamic multicast routing in survivable EONs. We compare various protection methods that may be applied to protect multicast sessions in EONs. For this purpose, we adapt two dynamic routing algorithms with additional survivability constraints and the possibility to change the modulation format at the regeneration nodes. Using realistic assumptions on EONs and representative network topologies, a wide range of simulations is run. First, we show the results to indicate advantages and disadvantages of various protection methods. In addition, we show gain of enabling partial protection of receivers in multicast trees. The results clearly show that various QoS levels for multicast protection allow to save optical network resources, thus, accept more incoming traffic in the network.