Linear bounds for on-line Steiner problems
Information Processing Letters
Multicast tree generation in networks with asymmetric links
IEEE/ACM Transactions on Networking (TON)
On-line algorithms for Steiner tree problems (extended abstract)
STOC '97 Proceedings of the twenty-ninth annual ACM symposium on Theory of computing
Online computation and competitive analysis
Online computation and competitive analysis
A general approach to online network optimization problems
SODA '04 Proceedings of the fifteenth annual ACM-SIAM symposium on Discrete algorithms
Resource optimization in QoS multicast routing of real-time multimedia
IEEE/ACM Transactions on Networking (TON)
On-line generalized Steiner problem
Theoretical Computer Science - Special issue: Online algorithms in memoriam, Steve Seiden
A survey of combinatorial optimization problems in multicast routing
Computers and Operations Research
Improved bounds for the online steiner tree problem in graphs of bounded edge-asymmetry
SODA '07 Proceedings of the eighteenth annual ACM-SIAM symposium on Discrete algorithms
On the approximability of some network design problems
ACM Transactions on Algorithms (TALG)
Probabilistic computations: Toward a unified measure of complexity
SFCS '77 Proceedings of the 18th Annual Symposium on Foundations of Computer Science
A Near-Tight Bound for the Online Steiner Tree Problem in Graphs of Bounded Asymmetry
ESA '08 Proceedings of the 16th annual European symposium on Algorithms
Hi-index | 0.00 |
A central issue in the design of modern communication networks is the provision of Quality-of-Service (QoS) guarantees at the presence of heterogeneous users. For instance, in QoS multicasting, a source needs to efficiently transmit a message to a set of receivers, each requiring support at a different QoS level (e.g., bandwidth). This can be formulated as the Priority Steiner tree problem: Here, each link of the underlying network is associated with a priority value (namely the QoS level it can support) as well as a cost value. The objective is to find a tree of minimum cost that spans all receivers and the source, such that the path from the source to any given receiver can support the QoS level requested by the said receiver. The problem has been studied from the point of view of approximation algorithms. In this paper we introduce and address the on-line variant of the problem, which models the situation in which receivers join the multicast group dynamically. Our main technical result is a tight bound on the competitive ratio of $\Theta \left (\min \left \{b \log \frac{k}{b},k \right \} \right)$ (when k b ), and ***(k ) (when k ≤ b ), where b is the total number of different priority values and k is the total number of receivers. The bound holds for undirected graphs, and for both deterministic and randomized algorithms. For the latter class, the techniques of Alon et al. [Trans. on Algorithms 2005] yield a O (logk logm )-competitive randomized algorithm, where m is the number of edges in the graph. Last, we study the competitiveness of online algorithms assuming directed graphs; in particular, we consider directed graphs of bounded edge-cost asymmetry.