The increase of the instability of networks due to Quasi-Static link capacities

Dimitrios Koukopoulos, Marios Mavronicolas, Paul Spirakis
2007 Theoretical Computer Science  
In this work, we study the impact of the dynamic changing of the network link capacities on the stability properties of packetswitched networks. Especially, we consider the Adversarial, Quasi-Static Queuing Theory model, where each link capacity may take on only two possible (integer) values, namely 1 and C > 1 under a (w, ρ)-adversary. We obtain the following results: • Allowing such dynamic changes to the link capacities of a network with just ten nodes that uses the LIS (Longest-in-System)
more » ... otocol for contention-resolution results in instability at rates ρ > √ 2 − 1 and for large enough values of C. • The combination of dynamically changing link capacities with compositions of contention-resolution protocols on network queues suffices for similar instability bounds: The composition of LIS with any of SIS (Shortest-in-System), NTS (Nearest-to-Source), and FTG (Furthest-to-Go) protocols is unstable at rates ρ > √ 2 − 1 for large enough values of C. • The instability bound of the network subgraphs that are forbidden for stability is affected by the dynamic changes to the link capacities: we present improved instability bounds for all the directed subgraphs that were known to be forbidden for stability on networks running a certain greedy protocol.
doi:10.1016/j.tcs.2007.04.008 fatcat:ifcgnls4abgz5gnteyx4eu3g7i