{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,4]],"date-time":"2026-05-04T13:43:08Z","timestamp":1777902188478,"version":"3.51.4"},"reference-count":20,"publisher":"SAGE Publications","issue":"1-2","license":[{"start":{"date-parts":[[2010,5,24]],"date-time":"2010-05-24T00:00:00Z","timestamp":1274659200000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"content-domain":{"domain":["journals.sagepub.com"],"crossmark-restriction":true},"short-container-title":["SIMULATION"],"published-print":{"date-parts":[[2011,1]]},"abstract":"<jats:p>ns-2 is a well known network simulator, recently extended with improvements to its emulation facility. Real-time constraints and the boundary between real-world and simulated entities impose scalability and accuracy limitations, and distort the simulated network as perceived by the involved real-world applications. This paper presents results from a performance evaluation of the ns-2 emulation facility. By carrying out emulation experiments at different scales and in different scenarios, we identify scalability limitations and quantify the emulation accuracy. We find throughput limits using high- and low-end computers, and a significant throughput decrease when increasing the number of involved real-world applications. Furthermore, we show how the end-to-end delay increases with both the traffic load and the number of real-world applications. In experiments with many applications, we also uncover significant variations in throughput and end-to-end delay among flows. Finally, our jitter measurements indicate how kernel scheduling causing bursty traffic transmission is responsible for most jitter. This effect is most often relatively modest, yet somewhat variable for experiments including several applications. Based on analysis of our results, we propose a set of modifications of the system that improves the performance. Our implementation of one of these modifications are demonstrated to increase throughput significantly while reducing the variation among flows. Implementation and evaluation of the remaining modifications is reserved for future work.<\/jats:p>","DOI":"10.1177\/0037549710370215","type":"journal-article","created":{"date-parts":[[2010,5,24]],"date-time":"2010-05-24T23:24:26Z","timestamp":1274743466000},"page":"45-65","update-policy":"https:\/\/doi.org\/10.1177\/sage-journals-update-policy","source":"Crossref","is-referenced-by-count":7,"title":["Accuracy and scalability of ns-2\u2019s distributed emulation extension"],"prefix":"10.1177","volume":"87","author":[{"given":"Stein","family":"Kristiansen","sequence":"first","affiliation":[{"name":"University of Oslo, Gaustadall\u00e8en 23, N-0371\rOslo, Norway, steikr@ifi.uio.no"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Thomas","family":"Plagemann","sequence":"additional","affiliation":[{"name":"University of Oslo, Gaustadall\u00e8en 23, N-0371\rOslo, Norway"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"179","published-online":{"date-parts":[[2010,5,24]]},"reference":[{"key":"atypb1","volume-title":"09: Proceedings of the 2nd International Conference on Simulation Tools and Techniques"},{"key":"atypb2","unstructured":"Wetherall, D. OTcl. Online software: otcl-tclcl. sourceforge.net\/otcl"},{"key":"atypb3","first-page":"205","year":"2005","journal-title":"Kommunikation in Verteilten Systemen (KiVS)"},{"key":"atypb4","first-page":"29","year":"2004","journal-title":"Distributed Simulation and Real-Time Applications"},{"key":"atypb5","first-page":"329","year":"2005","journal-title":"New Trends in Computer Networks"},{"key":"atypb6","volume-title":"HOWTO: Wireless Network Emulation Using ns-2 and Distributed Applications","year":"2004"},{"key":"atypb7","unstructured":"A Collaboration Between Researchers at US Berkley, LBL, USC\/ISI, and Xerox PARC. 2006 . ns-2 Manual The VINT Project."},{"key":"atypb8","volume-title":"Universal TUN\/TAP driver, Online software"},{"key":"atypb9","volume-title":"Online software"},{"key":"atypb10","unstructured":"Kristiansen S.ns-2 Emulation: Performance Evaluation and Improvement Proposals. Master Thesis. University of Oslo, Department of Informatics, 2008."},{"key":"atypb11","volume-title":"Parallel\/ Distributed ns","year":"2000"},{"key":"atypb12","volume-title":"Proceedings 7th International Symposium"},{"key":"atypb13","volume-title":"Net:Bridge, Online software"},{"key":"atypb14","doi-asserted-by":"crossref","unstructured":"G\u00f6kt\u00fcrk E. A.Stance on Emulation and Testbeds, and a Survey of Network Emulators and Testbeds. Proceedings of ECMS2007.","DOI":"10.7148\/2007-0503"},{"key":"atypb15","volume-title":"2nd International Conference"},{"key":"atypb16","volume-title":"02: Proceedings of the 5th Symposium on Operating Systems Design and Implementation SPECIAL ISSUE: Cluster Resource Management"},{"key":"atypb17","volume-title":"Proceedings. IEEE International Symposium"},{"key":"atypb18","unstructured":"Bhatia S., Motiwala M., M\u00fchlbauer W., Valancius V., Bavier A., Feamster N., Peterson L., and Rexford J.Hosting Virtual Networks on Commodity Hardware. Georgia Tech Computer Science, 2008."},{"key":"atypb19","volume-title":"\u201902: Proceedings of the 5th Symposium on Operating Systems Design and Implementation SPECIAL ISSUE: Peer-to-peer Infrastructure"},{"key":"atypb20","volume-title":"Online software and documentation"}],"container-title":["SIMULATION"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1177\/0037549710370215","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1177\/0037549710370215","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,1]],"date-time":"2026-05-01T11:22:25Z","timestamp":1777634545000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.sagepub.com\/doi\/10.1177\/0037549710370215"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2010,5,24]]},"references-count":20,"journal-issue":{"issue":"1-2","published-print":{"date-parts":[[2011,1]]}},"alternative-id":["10.1177\/0037549710370215"],"URL":"https:\/\/doi.org\/10.1177\/0037549710370215","relation":{},"ISSN":["0037-5497","1741-3133"],"issn-type":[{"value":"0037-5497","type":"print"},{"value":"1741-3133","type":"electronic"}],"subject":[],"published":{"date-parts":[[2010,5,24]]}}}