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Overview of the ORBIT Radio Grid Testbed for Evaluation of Next-Generation Wireless Network Protocols. WCNC 2005 D.Raychaudhuri , M.ott , S.Ganu , K.ramachandran , H.Kremo , R.Siracusa , H.Liu , Singh WINLAB, Rutgers U niversity 2011.4.11 Presented by Mingu Cho
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Overview of the ORBIT Radio Grid Testbed for Evaluation of Next-Generation Wireless Network Protocols WCNC 2005 D.Raychaudhuri, M.ott, S.Ganu, K.ramachandran, H.Kremo, R.Siracusa, H.Liu, Singh WINLAB, Rutgers University 2011.4.11 Presented by Mingu Cho mgcho@mmlab.snu.ac.kr
Contents • Radio channel characteristic • Limitation • ORBIT testbed • Requirement • Overall architecture • HW / SW component • Experiment • Conclusion MMLAB
Radio channel characteristic • Radio channel properties depend on specific wireless node locations and surroundings • Physical layer bit-rates and error-rates are time-varying • Shared medium layer-2 protocols on the radio link have a strong impact on network performance MMLAB
Limitation • Primarily simulation based or small in-house experimental setups • Difficult to repeat same experiments • Excessive setup and data collection times Hinder rapid prototyping and experimentation MMLAB
ORBIT testbed MMLAB
Background • Seeded by NSF grant under the Networking Research Testbeds (NRT) program • Collaborative effort: Rutgers, Columbia, and Princeton, along with industrial partners Lucent Bell Labs, IBM Research and Thomson • Developed and operated by WINLAB, Rutgers University MMLAB
Requirement • scalability, in terms of the total number of wireless nodes (~100’s) • reproducibilityof experiments which can be repeated with similar environments to get similar results • extensive measurements capabilityat radio PHY, MAC and network levels, with the ability to correlate data across layers in both time and space MMLAB
Requirement (cont’d) • remote access testbed capable of unmanned operation and the ability to robustly deal with software and hardware failures • open-access flexibilitygiving the experimenter a high level of control over protocols and software used on the radio nodes MMLAB
ORBIT: Indoor Grid Implemented part Not yet MMLAB
Hardware component • ORBIT radio nodes • 1-GHz processor with 512 MB of RAM • 2 wireless mini-PCI 802.11 a/b/g interfaces • Chassis manager : remotely monitor the status of each radio node’s hardware • Instrumentation subsystem • Provide capabilities for measurement of radio signal levels & create artificial RF interference MMLAB
Hardware component (cont’d) • Independent WLAN monitor system • Provide MAC/network layer view of radio grid’s components • Support severs • Front-end servers for web services • Back-end servers for experimentation and data storage MMLAB
Software component • Software packages and libraries developed to support both application/protocol evaluations • Common libraries for traffic generation, measurement and collection • Easy hooks to enable "expert" • To develop their own applications, protocol stacks, MAC layer modifications and/or other experiments MMLAB
Control software • Node Handler • Disseminate experiment scripts using multicast to the Node Agent • Node Agent • Reports back the state of experiment command execution to the Node Handler • Disk-Loading Server • Enable to quick re-imaging of hard disks on the nodes as per the requirements of the user MMLAB
Measurement software • ORBIT Measurement Library (OML) • Filters to be applied to each measured metric • Collection Server (CS) • Collect the reported measurements MMLAB
Experiment MMLAB
Experiment flow • The experiment details are translated into a script • The information is disseminated by Node Handler • The Node Agent executes the script MMLAB
Experiment 1 • To study the effect of 802.11b interference on the performance of a link under test • Consist of 8 nodes, send UDP packets • 6 interfering nodes, send UDP packets MMLAB
Experiment 2 • Effect of varying transmit power of sender on the performance in the presence of interferers • Demonstrate the effect of changing the transmit power of sender-receiver link • One sender-receiver pair • 6 interferers MMLAB
Conclusion • Present the design of a novel radio grid emulator testbed that facilitate a broad range of experimental research on next-generation protocols & applications • Provide sample experiments as proof-of-concept validation of the testbeddesign MMLAB
Q & A MMLAB