"Distributed Storage Control Algorithms for
George Iosifidis, Iordanis Koutsopoulos, and Georgios Smaragdakis.
IEEE/ACM Transactions on Networking, 25(3), June 2017.
Recent technological advances have rendered storage
a readily available resource, yet there exist few examples that
consider it for enhancing network performance. We revisit innetwork
storage and we evaluate its usage as an additional degree
of freedom in network optimization. We consider the network design
problem of maximizing the volume of end-to-end transferred
data and we derive storage allocation (placement) solutions. We
show that different storage placements have different impact on
the performance of the network and we introduce a systematic
methodology for the derivation of the optimal one. Accordingly,
we provide a framework for the joint optimization of routing
and storage control (usage) in dynamic networks for the case
of a single commodity transfer. The derived policies are based
on time-expanded graphs and ensure maximum performance
improvement with minimum possible storage usage. We also
study the respective multiple commodity problem where the
network link capacities and node storage resources are shared by
the different commodities. A key advantage of our methodology is
that it employs algorithms that are applicable to both centralized
as well as to distributed execution in an asynchronous fashion,
thus, no tight synchronization is required among the various
involved storage and routing devices in an operational network.
We also present an extensive performance evaluation study using
the backbone topology and actual traffic traces from a large
European Internet Service Provider, and a number of synthetic
network topologies. Our results show that indeed our approach
offers significant improvements in terms of delivery time and
transferred traffic volume.