Rothvoß, Thomas
Sanità, Laura
On the Complexity of the Asymmetric VPN Problem
12th Intl. Workshop on Approximation Algorithms for Combinat
12th Intl. Workshop on Approximation Algorithms for Combinat
12th Intl. Workshop on Approximation Algorithms for Combinat
12th Intl. Workshop on Approximation Algorithms for Combinat
Network design
approximation algorithms
NP-hardness
2009
2009
We give the first constant factor approximation algorithm for the asymmetric Virtual Private Network (VPN) problem with arbitrary concave costs. We even show the stronger result, that there is always a tree solution of cost at most 2 OPT and that a tree solution of (expected) cost at most 49.84 OPT can be determined in polynomial time. Furthermore, we answer an outstanding open question about the complexity status of the so called balanced VPN problem by proving its NP-hardness.
Springer
12th Intl. Workshop on Approximation Algorithms for Combinat
Conference Papers
10.1007/978-3-642-03685-9_25