Dynamic on-demand defragmentation in flexible bandwidth elastic optical networks

Abstract

While flexible bandwidth elastic optical networking is a promising direction for future networks, the spectral fragmentation problem in such a network inevitably raises the blocking probability and significantly degrades network performance. This paper addresses the spectral defragmentation problem using an auxiliary graph based approach, which transforms the problem into a matter of finding the maximum independent set (MIS) in the constructed auxiliary graph. The enabling technologies and defragmentation-capable node architectures, together with heuristic defragmentation algorithms are proposed and evaluated. Simulation results show that the proposed min-cost defragmentation algorithms can significantly reduce the blocking probability of incoming requests in a spectrally fragmented flexible bandwidth optical network, while substantially minimizing the number of disrupted connections.

Class-based first-fit spectrum allocation with fragmentation avoidance for dynamic flexgrid optical networks

“…There are two types of fragmentation avoidance algorithms: reactive and proactive. Reactive defragmentation policies are triggered once the spectrum becomes heavily fragmented [17], [18], [19]. On the other hand, proactive fragmentation avoidance has the advantage over reactive defragmentation schemes that it does not require reconfiguration of existing connections which may cause disruption for live connections [16].…”

Performance evaluation of non-hitless spectrum defragmentation algorithms in elastic optical networks

“…2 (s, t) shows how the connections a and e had to be rerouted for d to be allocated. In [24], Yin et. al.…”

Statistical analysis of blocking probability and fragmentation based on Markov modeling of elastic spectrum allocation on fiber link

“…Thus, it is desirable for network operators to periodically re-optimize the network. In [18,19], authors addressed the defragmentation problem assuming full spectrum retuning. However, optical devices, which achieve such defragmentation cycle, can be quite expensive and even more importantly, defragmentation might interfere with existing traffic.…”