QOMB Wireless Network Emulation Testbed: Evaluation and Case Study Razvan Beuran National Institute of Information and Communications Technology 2-12 Asahidai, Nomi, Ishikawa, Japan razvan@nict.go.jp Lan Tien Nguyen Japan Advanced Institute of Science and Technology 1-1 Asahidai, Nomi, Ishikawa, Japan lannt@jaist.ac.jp Yoichi Shinoda Japan Advanced Institute of Science and Technology 1-1 Asahidai, Nomi, Ishikawa, Japan shinoda@jaist.ac.jp ABSTRACT This paper presents several evaluation tests, as well as a case study of large-scale wireless network emulation exper- iments performed using QOMB, the wireless network emu- lation testbed at the National Institute of Information and Communications Technology, Hokuriku Research Center in Ishikawa, Japan. The evaluation tests demonstrate the ac- curacy of wireless network emulation using QOMB in single and multi-hop settings, as well as in scenarios involving node mobility. The large-scale experiments illustrate the most im- portant features of QOMB and its versatility by an OLSR protocol study in a MANET scenario including 50 emulated mobile nodes. Categories and Subject Descriptors I.6.6 [Simulation and Modeling]: Simulation Output Anal- ysis General Terms Experimentation, Measurement, Verification Keywords Wireless network emulation, wireless network testbed, OLSR, MANET, large-scale experiments 1. INTRODUCTION Wireless network technologies such as WLAN are now widely deployed in corporations, universities, homes and even public spaces. They are used from terminals with a wide range of specifications and processing power, in both static and mobile settings. Other wireless network technolo- gies, such as ZigBee or WiMAX, have appeared in recent years to address new user needs, as well as the limitations of existing technologies. Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. WiNTECH’10, September 20, 2010, Chicago, Illinois, USA. Copyright 2010 ACM 978-1-4503-0140-4/10/09 ...$10.00. The realistic evaluation of network applications and pro- tocols running over such wireless technologies plays a signifi- cant role in understanding their performance characteristics. It also contributes to their improvement, by allowing to con- duct the necessary R&D testing. The two key requirements for making it possible to per- form realistic assessments of network applications and pro- tocols are: • Carry out repeatable controlled experiments with the applications or protocols under test; • Use scenarios that are sufficiently close to reality in terms of experiment conditions and scale. Testbeds may be the ideal solution in this context, both from the point of view of repeatability and experiment size. In this paper we focus on the wireless network emulation testbed QOMB, designed and implemented by the National Institute of Information and Communications Technology, Hokuriku Research Center in Ishikawa, Japan. We first present several validation experiments done with QOMB that prove the accuracy of its wireless network em- ulation mechanisms. Then we use the OLSR protocol as a case study to demonstrate that QOMB addresses the two aforementioned requirements. The case study uses a MANET scenario that includes 50 mobile nodes, and experimentally quantifies the influence of the transmission power on the net- work topology that is being built in real time by a widely- deployed OLSR implementation. The paper is organized as follows. In Section 2 we discuss the main design elements, as well as the most important features of QOMB. Then we proceed in Section 3 to show several of the validation tests that we have carried out on QOMB to evaluate its accuracy. Following that, in Section 4, we present several large-scale OLSR experiments that we have performed using QOMB. Section 5 discusses related work in the field of wireless network testbeds, and the dif- ferences with respect to QOMB. We end the paper with conclusions and references. 2. QOMB DESIGN The QOMB testbed was created by integrating the wire- less network emulator QOMET [1] with the large-scale net- work experiment environment StarBED [6]. QOMB has been presented in [2], and we summarize here its most im- portant design aspects and features. 1