Throughput Maximization of Virtual Machine Communications in Bandwidth-Constrained Data Centers

In this paper we study a new algorithmic problem that maximizes the throughput of virtual machine (VM) communication in bandwidth-constrained data centers. Given a set of VM pairs with different bandwidth demands that are already placed inside cloud data centers, we study how to allocate the network bandwidth to the VM pairs to accommodate maximum number of VM communication while considering that cloud data centers have limited bandwidths. We refer to this throughput maximization problem as VMB. Due to the massive growth of cloud communication traffic in recent years and that service providers attempt to accommodate as many VM applications as possible in order to maximize their profits, VMB is an important problem to study. First we prove that VMB is NP-hard. Then we propose a suite of algorithms to solve VMB. In particular, we propose an approximation algorithm that achieves approximation ratio of
$1 /\left(2 \cdot\left\lceil\frac{B}{b}\right\rceil \cdot\vert E\vert^{1 /\left(\left\lceil\frac{B}{b}\right\rceil+1\right)}+1\right)$
, where
$\vert E\vert$
is the number of edges in the data center network,
$B$
is the average bandwidth capacity on edges, and
$b$
is the average bandwidth demand of each request. We show through simulations that our algorithms are effective in accommodating large number of VM communications under different network parameters. In particular, our approximation algorithm accommodates more than 60% of total VM communications, and up to 38% more VM pairs compared to existing research.