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1

A Constrained Maximum Available Frequency Slots on Path Based Online Routing and Spectrum Allocation for Dynamic Traffic in Elastic Optical Networks

Khan Akhtar Nawaz

International Journal of Electronics and Telecommunications

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2020

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Vol. 66, No. 4

707--714

EN

Elastic optical networking is a potential candidate to support dynamic traffic with heterogeneous data rates and variable bandwidth requirements with the support of the optical orthogonal frequency division multiplexing technology (OOFDM). During the dynamic network operation, lightpath arrives and departs frequently and the network status updates accordingly. Fixed routing and alternate routing algorithms do not tune according to the current network status which are computed offline. Therefore, offline algorithms greedily use resources with an objective to compute shortest possible paths and results in high blocking probability during dynamic network operation. In this paper, adaptive routing algorithms are proposed for shortest path routing as well as alternate path routing which make routing decision based on the maximum idle frequency slots (FS) available on different paths. The proposed algorithms select an underutilized path between different choices with maximum idle FS and efficiently avoids utilizing a congested path. The proposed routing algorithms are compared with offline routing algorithms as well as an existing adaptive routing algorithm in different network scenarios. It has been shown that the proposed algorithms efficiently improve network performance in terms of FS utilization and blocking probability during dynamic network operation.

2

Investigation of dynamic routing and spectrum allocation methods in elastic optical networks

Biernacka E., Domżał J., Wójcik T.

International Journal of Electronics and Telecommunications

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2017

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Vol. 63, No. 1

85--92

EN

The introduction of flexible frequency grids and advanced modulation techniques to optical transmission, namely an elastic optical network, requires new routing and spectrum allocation techniques. In this paper, we investigate dynamic two-step routing and spectrum allocation (RSA) methods for elastic optical networks. K-shortest path-based methods as well as spectrum allocation methods are analysed and discussed. Experimental verification of the investigated techniques is provided using simulation software. Simulation results present effectiveness of routing and spectrum allocation methods for analyzed networks using requested bandwidth of connections. Moreover, performance of shortest path first methods improves considerably when a number of candidate paths increases in the UBN24 topology.

3

Routing and Spectrum Assignment for Constant Bit Rate Connections in Spectrum Sliced Elastic Optical Path Networks

Olszewski I.

Przegląd Elektrotechniczny

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2015

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R. 91, nr 7

124-128

EN

In this paper a heuristic algorithm for finding an optical path in elastic optical path networks is proposed. The proposed algorithm for connection requests finds a spectrum required from an aggregated spectrum of the path belonging to a set of shortest paths measured by the number of links. It has been shown that the proposed algorithm rejects definitely fewer connection requests than the well-known algorithms solving the same problem.

PL

W pracy zaproponowano heurystyczny algorytm wyboru ścieżek w elastycznych sieciach optycznych. Zaproponowany algorytm zajmuje dla napływającego żądania wymagane pasmo w zagregowanym widmie ścieżki, należącej do zbioru najkrótszych ścieżek mierzonych liczbą łączy. W pracy wykazano, że algorytm ten odrzuca mniejszą liczbę żądań niż znane algorytmy minimalizujące rzeczywistą długość ścieżki.

4

Elastyczne sieci optyczne

Biernacka E., Lasoń A.

Telekomunikacja i Techniki Informacyjne

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2013

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nr 1-2

5--17

PL

Artykuł przybliża koncepcję elastycznej sieci optycznej i charakterystyczne zagadnienia związane z jej implementacją. Przedstawiono w nim standardy styków optycznych sieci Ethernet 40 Gbit/s i 100 Gbit/s zawarte w dokumencie IEEE 802.3ba. Następnie opisano szczelinowy charakter widma elastycznej sieci optycznej, porównując ze sztywnym podziałem częstotliwości DWDM. Nakreślono problem planowania i dynamicznej alokacji zasobów w sieci.

EN

The paper studies a novel concept of elastic optical network and selected network–level requirements of next generation optical networks. It investigates new optical IEEE 802.3ba Physical Layer Specification. Next it is compared the fixed-grid wavelength division multiplexing optical networks with flexible-grid elastic optical networks. It is important to define routing and spectrum assignment RSA algorithms, which are required for network planning and dynamic resource allocation. Mobile lab, radiocommunication services testing, radiocommunication networks measurements.

5

Algorithms of Routing and Spectrum Assignment in Spectrum Flexible Transparent Optical Networks

Olszewski I.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 10

248-253

EN

The considered problem of routing and spectrum assignment (RSA) takes into consideration minimizing the length of the transmission distance under spectrum continuity constraints and the relationship between the traffic bitrates and the spectrum bandwidth. The proposed algorithms constitute modifications of the well-known Dijkstra's algorithm. The obtained results show that a significant reduction in the number of rejected requests can be achieved by an appropriate selection of the scheme spectrum segments in the aggregated spectrum of the path but not by increasing the computational complexity of the algorithms.

PL

Rozważany problem rutingu I przypisania widma (RSA) obejmuje minimalizację długości ścieżki transmisyjnej przy warunkach nałożonych na ciągłość widma oraz zależność pomiędzy szybkością binarną i widmem pasma sygnału. Zaproponowane algorytmy stanowią modyfikację algorytmu Dijkstry. Uzyskane wyniki pokazują, że istotna redukcja liczby odrzuconych żądań może być uzyskana nie poprzez zwiększanie złożoności obliczeniowej algorytmu, ale poprzez odpowiedni schemat wyboru segmentu widma z zagregowanego widma ścieżki.