Efficient Reconfiguration of Virtual Topologies in Multilayer Hybrid Optical Networks

Multilayer Hybrid Optical Networks (MHONs) combine different switching paradigms in a single physical network, and they typically allow resource sharing between all the supported paradigms. Many of these architectures include the establishment of a virtual topology (by means of all optical circuits or lightpaths) in order to carry certain traffic types. A significant advantage of the virtual topologies is that they can be reconfigured, if required, in order to adapt to both traffic and network conditions. However, the reconfiguration has a cost: the number of packets lost during the reconfiguration process. Hence, it is necessary to develop efficient reconfiguration policies and algorithms in order to increase the performance of the network while maintaining the packet loss ratio under certain bounds. On the other hand, the virtual topology established in a MHON should use as less resources as possible (while fulfilling quality of service requirements), so that more resources become available for other paradigms supported by the MHON, and thereby improving their performance. In this paper we propose a new reconfiguration method to reduce the number or resources used by the virtual topology of a MHON, while maintaining the packet loss ratio and the congestion under user-defined bounds. A simulation study is also presented in order to show the efficiency of the novel method when compared with previous related work.