Browsing by Subject "Spectrum allocation"

Now showing 1 - 3 of 3

Open Access
Analytical performance modeling of elastic optical links with aligned spectrum allocation
(Elsevier BV North-Holland, 2015) Vaezi, K.; Akar, N.
Abstract Elastic optical networking has recently been proposed for use in optical transport networks to cope with increasingly heterogeneous and dynamic demand patterns. In this paper, we study the blocking performance of a multi-class elastic optical link for which a demand needs to be allocated a contiguous subset of the entire spectrum. This problem is different than the well-known blocking problem in multi-class multi-server loss systems due to the contiguous allocation constraint. We first propose a non-work-conserving aligned spectrum allocation policy which is shown to outperform the conventional first fit-based work-conserving allocation policy without alignment. Subsequently, for blocking performance of an aligned elastic optical link with up to three different traffic classes, we propose a novel and systematic order reduction procedure for MMPPs (Markov Modulated Poisson Process) and use this procedure as the numerical engine to approximately obtain the blocking probabilities. The proposed numerical algorithm is validated under various system and traffic parameters and is shown to be effectively usable as an instrument to dimension elastic optical links.
Open Access
Class-based first-fit spectrum allocation with fragmentation avoidance for dynamic flexgrid optical networks
(Elsevier BV, 2015) Yumer, R.; Akar, N.; Karasan, E.
A novel Class-Based First Fit (CBFF) spectrum allocation policy is proposed for dynamic flexgrid optical networks. The effectiveness of the proposed CBFF policy is compared with that of the First Fit (FF) policy for single-link and network scenarios. Throughput is shown to be consistently improved under the proposed CBFF policy with throughput gains of up to 15%, compared with the FF policy for the network scenarios we studied. The reduction in bandwidth blocking probability with CBFF with respect to FF increases as the link capacities increase. Throughput gains of CBFF compared with those of FF are more significant under alternate routing as opposed to fixed routing.
Open Access
Mapping time-varying IP traffic to flexible optical paths in flexgrid optical networks
(Springer New York LLC, 2015) Tunc C.; Akar, N.
A spectrum slot is the frequency range allocated to a single channel within a flexible grid, and its width needs to be an integer multiple of the so-called slot width granularity. The slot width of the spectrum slots to be used for an optical path in flexgrid optical networks can be adjusted in time to align with time-varying client traffic demand for both bandwidth and energy efficiency purposes. However, frequent adjustment of the slot width of optical paths places substantial signaling load on the control plane. In this paper, an online slot width adjustment mechanism is proposed for flexgrid optical networks under slot width update rate constraints in order to maintain the associated signaling load at acceptable levels. Real traffic traces are used to validate the effectiveness of the proposed mechanism.