Towards an Efficient and Exact Algorithm for Dynamic Dedicated Path Protection

Abstract

We present a novel algorithm for dynamic routing with dedicated path protection which, as the presented simulation results suggest, can be efficient and exact. We present the algorithm in the setting of optical networks, but it should be applicable to other networks, where services have to be protected, and where the network resources are finite and discrete, e.g., wireless radio or networks capable of advance resource reservation. To the best of our knowledge, we are the first to propose an algorithm for this long-standing fundamental problem, which can be efficient and exact, as suggested by simulation results. The algorithm can be efficient because it can solve large problems, and it can be exact because its results are optimal, as demonstrated and corroborated by simulations. We offer a worst-case analysis to argue that the search space is polynomially upper bounded. Network operations, management, and control require efficient and exact algorithms, especially now, when greater emphasis is placed on network performance, reliability, softwarization, agility, and return on investment. The proposed algorithm uses our generic Dijkstra algorithm on a search graph generated “on-the-fly” based on the input graph. We corroborated the optimality of the results of the proposed algorithm with brute-force enumeration for networks up to 15 nodes large. We present the extensive simulation results of dedicated-path protection with signal modulation constraints for elastic optical networks of 25, 50, and 100 nodes, and with 160, 320, and 640 spectrum units. We also compare the bandwidth blocking probability with the commonly-used edge-exclusion algorithm. We had 48,600 simulation runs with about 41 million searches.

Generic Dijkstra: correctness and tractability

“…In that article also the signal modulation constraint was considered, which we do not address here. The generic Dijkstra algorithm was adapted to solve the dynamic routing problem with dedicated path protection [3]. The algorithm was simulatively demonstrated to efficiently find exact results [4], [2].…”

“…A set C of candidate labels l ′ is produced when to a path described with label l an edge e is appended, which is denoted by l ⊕ e and defined by (3). We say that l ′ is derived from l. Labels l ′ have equal cost that depends on the cost of l and e, i.e., cost(l ′ ) = cost(l) ⊕ cost(e).…”

Towards an efficient and exact algorithm for dynamic dedicated path protection

“…3) Signal modulation model: We use the signal modulation model from [3], with M modulations available. For a demand requesting g units for the most spectrally-efficient modulation, the number of units needed to establish a connection of length d is given by (2), where r 1 is the reach of the least spectrally-efficient modulation, and r M is the reach of the most spectrally-efficient modulation.…”

“…Our novel contribution is the algorithm which efficiently and optimally solves the dynamic (a.k.a., online, i.e., we route a single demand in a loaded network) RWA, RSA and RMSA problems with DPP, along with its simulative performance evaluation, and a liberal open-source high-quality implementation using the Boost Graph Library [2].…”

Advances in Computer Recognition, Image Processing and Communications

“…The presented method complements the possibilities of a short-range optical network working in the flexible dense wavelength division multiplexing (DWDM) format, where chromatic dispersion compensation is not applied. In [ 9 ], the authors describe their algorithm for dynamic routing with dedicated path protection. They proposed the algorithm in the context of optical networks, but it can be applicable to other networks, where services have to be protected and the network resources are finite and discrete, e.g., wireless radio or networks capable of advance resource reservation.…”