CAM01-3: Connection Preemption in Multi-Class Networks

Abstract

We address the problem of connection preemption in a multi-class network environment. Our objective is: i) to minimize the number of preempted connections, and ii) to minimize the total preempted bandwidth, in that order. We show that this problem is NP-complete by reducing it to a well-known NP complete problem -the subset sum problem. Therefore, a known polynomial time algorithm, such as Minn Conn [1], to solve this problem is suboptimal.We present an optimal algorithm with exponential complexity that can be used when the network load is light. We also present a fully polynomial time approximation algorithm that performs within a bounded factor from the optimal, and can be used in large networks having thousands of connections. We compare the performance of exact and approximate algorithms in a practical scenario by conducting simulations on a network representing twenty largest metros in the U.S. The simulations show that, on average, the approximate algorithm preempts bandwidth which is only a small fraction more as compared to that preempted by the exact algorithm, but is an order of magnitude more efficient in terms of execution time.

Advance bandwidth reservation with deadline constraint in high-performance networks

“…In [13], Garay et al proved the NP-completeness of the IR preemption problem by reducing the minimal cover problem to it and also proposed a heuristic that could be implemented in a centralized manner. In [14], Dogar et al addressed the problem to minimize both the number of preempted connections and the total preempted bandwidth in that order. These preemption schemes work well in network environments where a local node makes a decision on which set of IR users to be preempted such that the number of IR preemptions is minimized.…”

“…Note that the IR-Preemption problem is defined with deterministic cost models and its NP-completeness has been established in [14].…”

Preemption and QOS management algorithms for coordinated and uncoordinated base stations

“…To avoid infinite iterations, we define a stop criterion consisting in the fulfillment of the power constraint with a certain tolerance represented by ε. Thus, the computed required power will be equal to or smaller than 2 (1 + ε)PBS. An example for the application of such an algorithm is presented in Fig.…”

“…Preemption algorithms have been proposed for instance in routing [2,3] to free up enough resources whenever the residual bandwidth of a link is lower than the bandwidth request of a higher priority connection. How should the selection of users be performed or how much should the target rate be reduced are not straightforward decisions.…”