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Zusammenfassung:
This paper studies the multicast routing and admission control problem
on unit-capacity tree and mesh topologies in the throughput-model.
The problem is a generalization of the edge-disjoint paths problem and
is NP-hard both on trees and meshes.
We study both the offline and the online version of the problem:
In the offline setting, we give the first constant-factor approximation
algorithm for trees, and an O((log log n)^2)-factor approximation algorithm
for meshes.
In the online setting, we give the first polylogarithmic competitive
online algorithm for tree and mesh topologies. No polylogarithmic-competitive
algorithm is possible on general network topologies [Bartal,Fiat,Leonardi, 96],
and there exists a polylogarithmic lower bound on the competitive ratio
of any online algorithm on tree topologies [Awerbuch,Azar,Fiat,Leighton, 96].
We prove the same lower bound for meshes.