QoS Routing Under Multiple Additive Constraints: A Generalization of the LARAC Algorithm

• Published in: IEEE transactions on emerging topics in computing Vol. 4; no. 2; pp. 242 - 251
• Main Authors: Ying Xiao, Thulasiraman, Krishnaiyan, Xue, Guoliang, Yadav, Mamta
• Format: Journal Article
• Language: English
• Published: IEEE 01.04.2016
• Subjects: Algorithm design and analysis; algorithms; Approximation algorithms; Approximation methods; combinatorial optimization; Delays; Lagrangian relaxation; Optimization; QoS routing; Quality of service; Routing; combinatorial optimization; algorithms; QoS routing; Lagrangian relaxation
• ISSN: 2168-6750; 2168-6750
• DOI: 10.1109/TETC.2015.2428654

Consider a directed graph G(V, E), where V is the set of nodes and E is the set of links in G. Each link (u, v) is associated with a set of k+ 1 additive nonnegative integer weights C uv = (c uv , w uv 1 , w uv 2 ,⋯, w uv k ). Here, c uv is called the cost of link (u, v) and w uv i is called the i th delay of (u, v). Given any two distinguish nodes s and t, the QoS routing (QSR) problem QSR(k) is to determine a minimum cost s-t path such that the i th delay on the path is atmost a specified bound. This problem is NP-complete. The LARAC algorithm based on a relaxation of the problem is a very efficient approximation algorithm for QSR(1). In this paper, we present a generalization of the LARAC algorithm called GEN-LARAC. A detailed convergence analysis of GEN-LARAC with simulation results is given. Simulation results provide an evidence of the excellent performance of GEN-LARAC. We also give a strongly polynomial time approximation algorithm for the QSR(1) problem.