Publications

Auction-based Scheduling of Wireless Testbed Resources

Authors: Harris Niavis, Kostas Choumas, George Iosifidis, Thanasis Korakis and Leandros Tassiulas

Conference: WCNC, Instanbul, Turkey, 6 - 9 April 2014

Abstract: Experimentation in testbeds is gaining increasing ground as a necessary validation step for every theoretical study in communication networks. However, the first-come-first-served policy employed today by most testbeds does not ensure the fair and efficient utilization of their resources, which often lie idle. Ideally, every testbed should be utilized as much as possible and serve the most important requests. In this paper we introduce a novel resource scheduling mechanism for the wireless testbed NITOS. The proposed scheme is based on VCG auctions and includes an allocation and a pricing rule which induce the users to judiciously submit experiment requests. We prove theoretically and demonstrate numerically that this scheme ensures that the testbed resources (nodes and channels) are assigned to the users with the highest needs. Our mechanism can be incorporated in the next generation resource management systems for NITOS and similar testbeds.

Keywords: scheduling, auction-based, resource allocation, VCG auctions, testbed

Download paper: NITOS-incentives.pdf

Multirate Multicast: Optimal Algorithms and Implementation

Authors: Georgios S. Paschos, Chih-ping Li, Eytan Modiano, Kostas Choumas and Thanasis Korakis

Conference: INFOCOM, Toronto, Canada, 27 April - 2 May 2014

Abstract: Multirate multicast improves user quality but complicates network optimization. This paper introduces a novel control scheme to dynamically optimize multirate multicast. We present MMT, an adaptive policy which combines differential backlog scheduling and intelligent packet dropping, both based on local information. MMT is shown to maximize network throughput by adapting to changing conditions such as channel quality, network congestion, and device capabilities. Then, we study the problem of per-receiver network utility maximization. To maximize sum utility we propose the MMU policy, an extension of MMT with receiver-end flow control. Under the operation of both policies backlog sizes are deterministically bounded, which provides delay guarantees on delivered packets. An important feature of the proposed scheme is that it does not require source cooperation or centralized calculations. To illustrate its practicality, we present a prototype implementation in the NITOS wireless testbed. Experimental results verify the optimality of the scheme and its low complexity.

Download paper: kohoumas_infocom_2014_multirate.pdf

The TREND Experimental Activities on "Green" Communication Networks

Authors: I. Haratcherev, M. Meo, Y. Zhang, Y. Hu, A. Conte, Filip Idzikowski, L.ukasz Budzisz, Fatmeh Ganji, R. Bolla, O. Jaramildo Ortiz, R. Bruschi, A. Cianfrani, L. Chiaraviglio, A. Coiro, R. Gonzales, C. Guerrero, E. Ego, F. Matera, S. Keranidis, G. Kazdaridis and T. Korakis

Conference: in the Proceedings of the 24th Tyrrhenian International Workshop on Digital Communications (TIWDC), Genoa, Italy, September 2013

Abstract: Aimed at answering important questions about the energy demand of current telecom infrastructure and the design of sustainable and energy-efficient future networks, the research of a number of European partners is brought together in the TREND project. In this paper we present the achievements of the Work Package coordinating the experimental activities of the project - WP4. Although not presenting a completely finished portrait yet, the results shown help building a better global view on the “big picture” in the field of energy-efficient networking.

Download paper: The_TREND_Experimental_Activities_on_Green_Communication_Networks_2013.pdf

Experimentation on end-to-end performance aware algorithms in the federated environment of the heterogeneous PlanetLab and NITOS testbeds

Authors: Stratos Keranidis, Dimitris Giatsios, Thanasis Korakis, Iordanis Koutsopoulos, Leandros Tassiulas, Thierry Rakotoarivelo, Max Ott, Thierry Parmentelat

Journal: Elsevier Computer Networks, Special Issue on Future Internet Testbeds, 2013

The constantly increasing diversity of the infrastructure that is used to deliver Internet services to the end user, has created a demand for experimental network facilities featuring heterogeneous resources. Therefore, federation of existing network testbeds has been identified as a key goal in the experimental testbeds community, leading to a recent activity burst in this research field. In this paper, we present a federation scheme that was built during the Onelab 2 EU project. This scheme federates the NITOS wireless testbed with the wired PlanetLab Europe testbed, allowing researchers to access and use heterogeneous experimental facilities under an integrated environment. The usefulness of the resulting federated facility is demonstrated through the testing of an implemented end-to-end delay aware association scheme proposed for Wireless Mesh Networks. We present extensive experiments under both wired congestion and wireless channel contention conditions that demonstrate the effectiveness of the proposed approach in a realistic environment. The conducted experiments are also reproduced in a well established network simulator and a comparative study between the results obtained in the realistic and simulated environments is presented. Both the architectural building blocks that enable the federation of the testbeds and the execution of the experiment on combined resources, as well as the important insights obtained from the experimental results are described and analyzed, pointing out the importance of integrated experimental facilities for the design and development of the Future Internet.

Download paper: Keranidis_Federation_Elsevier_COMNET_2013.pdf