Designing least-cost nonblocking broadband networks
Journal of Algorithms
A flexible model for resource management in virtual private networks
Proceedings of the conference on Applications, technologies, architectures, and protocols for computer communication
Improved Steiner tree approximation in graphs
SODA '00 Proceedings of the eleventh annual ACM-SIAM symposium on Discrete algorithms
Provisioning a virtual private network: a network design problem for multicommodity flow
STOC '01 Proceedings of the thirty-third annual ACM symposium on Theory of computing
Reserving Resilient Capacity in a Network
SIAM Journal on Discrete Mathematics
Simpler and better approximation algorithms for network design
Proceedings of the thirty-fifth annual ACM symposium on Theory of computing
FOCS '97 Proceedings of the 38th Annual Symposium on Foundations of Computer Science
The Access Network Design Problem
FOCS '98 Proceedings of the 39th Annual Symposium on Foundations of Computer Science
An improved approximation algorithm for virtual private network design
SODA '05 Proceedings of the sixteenth annual ACM-SIAM symposium on Discrete algorithms
Virtual private network design: a proof of the tree routing conjecture on ring networks
IPCO'05 Proceedings of the 11th international conference on Integer Programming and Combinatorial Optimization
Approximation via cost sharing: Simpler and better approximation algorithms for network design
Journal of the ACM (JACM)
Infrastructure Leasing Problems
IPCO '07 Proceedings of the 12th international conference on Integer Programming and Combinatorial Optimization
Connected facility location via random facility sampling and core detouring
Journal of Computer and System Sciences
Tree embeddings for two-edge-connected network design
SODA '10 Proceedings of the twenty-first annual ACM-SIAM symposium on Discrete Algorithms
Provisioning a virtual private network under the presence of non-communicating groups
CIAC'06 Proceedings of the 6th Italian conference on Algorithms and Complexity
Improved approximation for single-sink buy-at-bulk
ISAAC'06 Proceedings of the 17th international conference on Algorithms and Computation
Design of trees in the hose model: The balanced case
Operations Research Letters
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Virtual private network design is the following NP-hard problem. We are given a communication network, represented as a weighted graph with thresholds on the nodes which represent the amount of flow that a node can send to and receive from the network. The task is to reserve capacities at minimum cost and to specify paths between every ordered pair of nodes such that all valid traffic-matrices can be routed along the corresponding paths. Recently, this network design problem has received considerable attention in the literature. It is motivated by the fact that the exact amount of flow which is exchanged between terminals is not known in advance and prediction is often illusive. The main contributions of this paper are as follows:Using Hu’s 2-commodity flow theorem, we provide a new lower bound on the cost of an optimum solution. Using this lower bound we reanalyze a simple routing scheme which has been described in the literature many times and provide a considerably stronger upper bound on its approximation ratio. We present a new randomized approximation algorithm for which, in contrast to earlier approaches from the literature, the resulting solution does not have tree structure. Finally we show that a combination of our new algorithm with the simple routing scheme yields a randomized algorithm with expected performance ratio 3.55 for virtual private network design. This is a considerable improvement of the previously best known approximation results (5.55 STOC’03, 4.74 SODA’05).