Blocking probability and fairness in two-rate Elastic Optical Networks

Blocking fairness in two-service EONs with uneven arrival rates

“…This paper extends the work in [9] by studying the trade-off between the achievable level of fairness and blocking probability in a number of traffic scenarios. The performance of the Two Rate Reservation (TRR) algorithm [9] is compared to other well-known RSA algorithms.…”

“…The work in [8] introduces an RSA algorithm that achieves perfect fairness at the cost of the increasing of the overall blocking probability. The study in [9] introduced an additional performance indicator to quantify the level of fairness (or unfairness) experienced by two types of service requests, each type requiring a distinct spectrum bandwidth under even arrival rates in two-service EONs. Two groups of service requests are considered, each group characterized by arrival rate, service time and a number of spectrum slices required.…”

An Analytical Model of Spectrum Fragmentation in a Two-Service Elastic Optical Link

“…An existing discrete event-driven simulation platform for EONs [7] has been modified to account for semi-flexible spectrum allocation. The EON simulator accounts for both the semi-flexible algorithm in [1] -according to which circuit requests are assigned slices in the spectrum using a first-fit assignment policy -and a randomfit policy, as described earlier in this paper.…”

“…For each node pair in the topology, 5 shortest paths are computed using hop-count as the metric. One of the five paths is chosen for each incoming circuit request -generated by a Poisson arrival process with source and destination pairs randomly and uniformly chosen, and with a circuit holding random time described by an exponential probability distributionbased on two RSA algorithms, i.e., the semi-flexible algorithm (Semiflex) [1] and the K Shortest Paths with first-fit policy (KSP FF) algorithm [7]. Spectrum or wavelength continuity is enforced along every circuit path.…”

“…The study in [6] defines two ways to quantify how serious the spectrum fragmentation problem is, instead of estimating the effect of fragmentation on the network performance. Simulation-based studies have shown that blocking probability in EON can be uneven, i.e., high-rate circuit requests are more likely to be blocked when compared to low-rate requests due to the shortage of contiguous available slices, e.g., [7]. Due to the complexity of the fragmentation phenomenon, a few analytical models have been proposed so far to rigorously quantify this problem [8].…”