Flexible optical network (FON) architectures are considered a very promising solution where spectrum resources are allocated within flexible frequency grids. These architectures must handle the spectrum more efficiently and must support on-demand elastic bandwidth provisioning. However, when multi-bandwidth services coexist without a suitable bandwidth management, blocking of wider spectrum calls increases compared to narrower spectrum calls. This unfairness effect limits FONs' performance, not fulfilling much of the promise they hold. In this letter we present a new specific variant of trunk reservation policies that can effectively deal with fast on-demand bandwidth provisioning. Through network simulations we show that trunk reservation is able to guarantee fairness and to equalize the performance of an entire network in terms of blocking probability and link utilization with different flexible spectrum allocation policies.

In this paper we show that the adoption of a simple weighted ordering heuristic strategy to find fixed shortest path routes in a topology can improve load-balancing and, consequently, network performance. We compared our fixed routing strategies against the $k$-shortest paths ($k$-SP) fixed-alternate routing strategy for three different mesh topologies considering fixed grid networks (FGNs) and elastic optical networks (EONs). The results show that our simple fixed routing strategies can improve network performance for an optical network system, even compared with the fixed alternate routing and always using the shortest path. Results also show that such easy strategies act mainly in longer routes, increasing their probability of use and balancing the link load distribution.

This paper investigates quality of service fairness in grid-less, multi-rate optical networks. By means of analytical modeling and simulation, results show that unfairness arises in absence of suitable control and that trunk reservation policies may solve the issue.

In this work we study the influence of the routing mechanisms when adopting a spectrum partitioning strategy in Flexible Optical Networks. Spectrum partitioning is considered because a complete sharing of the available spectrum cannot be implemented in the already deployed optical network. Spectrum partitioning allows the coexistence of different spectrum usage architectures. The spectrum partitioning strategy influences the service blocking probability as well as does the routing mechanism. Therefore, this influence should be considered for future studies aiming at service fairness, by considering path lengths for hybrid network architectures.