S.Y. Wang and Y.W. Li, “ Evaluations of Intelligent Traffic Signal Control Algoritms under Realistic Landmark-based Traffic Patterns over the NCTUns Network Simulator,” IEEE ITSC 2012 (International Conference on Intelligent Transportation Systems), September 16 - 19, 2012, Anchorage, Alaska, USA.
S.Y. Wang and Y.M. Huang, “ NCTUns Distributed Network Emulator,” Internet Journal, Vol. 4, Num. 2, pp. 61-94, Nova Science Publisher (ISSN 1937-3805), 2012
S.Y. Wang, P.F. Wang, Y.W. Li, and L.C. Lau, “Design and Implementation of A More Realistic Radio Propagation Model for Wireless Vehicular Networks over the NCTUns Network Simulator,” IEEE WCNC 2011 (Wireless Communications and Networking Conference 2011), March 28 – 31, 2011, Cancun, Mexico.
S.Y. Wang, C.C. Lin, and C.C. Huang, “NCTUns Tool for Evaluating the Performances of Real-life P2P Applications,” a chapter of the “Peer-to-Peer Networks and Internet Policies” book, (ISBN 978-1-60876-287-3, published by Nova Science Publishers in 2010)
S.Y. Wang, H.Y. Chen, and S.W. Chuang, “NCTUns Tool for IEEE 802.16j Mobile WiMAX Relay Network Simulations,” a chapter of the “Computer Science Research and Technology” book, (ISBN: 978-1-61728-688-9, published by Nova Science Publishers in 2009)
S.Y. Wang and C.L. Chou, “NCTUns Tool for Wireless Vehicular Communication Network Researches,” Simulation Modelling Practice and Theory, Vol. 17, No. 7, pp. 1211-1226, August 2009.
S.Y. Wang and R.M. Huang, “NCTUns Tool for Innovative Network Emulations,” a chapter of the “Computer-Aided Design and Other Computing Research Developments” book, (ISBN: 978-1-60456-860-8, published by Nova Science Publishers in 2009)
S.Y. Wang and C.C. Lin, "NCTUns 5.0: A Network Simulator for IEEE 802.11(p) and 1609 Wireless Vehicular Network Researches," 2nd IEEE International Symposium on Wireless Vehicular Communications, September 21–22, 2008, Calgary, Canada. (demo paper)
S.Y. Wang and C.L. Chou, "NCTUns Simulator for Wireless Vehicular Ad Hoc Network Research", a chapter of the "Ad Hoc Networks: New Research" book (Nova Science Publishers, ISBN: 978-1-60456-895-0)
S.M. Huang, Y.C. Sung, S.Y. Wang, and Y.B. Lin, “NCTUns Simulation Tool for WiMAX Modeling,” Third Annual International Wireless Internet Conference, October 22 – 24, 2007, Austin, Texas, USA. (EI and ISI indexed, sponsored by ICST, ACM, EURASIP)
S.Y. Wang, C.L. Chou, Y.H. Chiu, Y.S. Tseng, M.S. Hsu, Y.W. Cheng, W.L. Liu, and T.W. Ho, “NCTUns 4.0: An Integrated Simulation Platform for Vehicular Traffic, Communication, and Network Researches,” 1st IEEE International Symposium on Wireless Vehicular Communications, September 30 – October 1, 2007, Baltimore, MD, USA
S.Y. Wang, C.L. Chou, C.C. Lin, “The Design and Implementation of the NCTUns Network Simulation Engine”, Elsevier Simulation Modelling Practice and Theory, 15 (2007) 57 – 81.
S.Y. Wang and K.C. Liao, “Innovative Network Emulations using the NCTUns Tool”, as a book chapter of the “Computer Networking and Networks” book, (ISBN 1-59454-830-7, published by Nova Science Publishers in 2006)
S.Y. Wang and Y.B. Lin, “NCTUns
Network Simulation and Emulation for Wireless Resource Management”,
Wiley Wireless Communications and
S.Y. Wang, C.L. Chou, C.H. Huang, C.C. Hwang, Z.M. Yang, C.C. Chiou, and C.C. Lin, "The Design and Implementation of the NCTUns 1.0 Network Simulator", Computer Networks, Vol. 42, Issue 2, June 2003, pp. 175-197.
S.Y. Wang, “NCTUns
S.Y. Wang and H.T. Kung, "A New Methodology for Easily Constructing Extensible and High-Fidelity TCP/IP Network Simulators", Computer Networks, Vol. 40, Issue 2, October 2002, pp. 257-278.
S.Y. Wang and H.T. Kung, "A
Simple Methodology for Constructing Extensible and High-Fidelity TCP/IP Network
Simulators", IEEE INFOCOM'99, March 21-25, 1999,
Enter the NCTUns web site here. The NCTUns 6.0 package, its GUI user manual, its protocol developer manual, and its 83 demo video clips are stored inside. The nctuns mailing list can be accessed here at http://nsl10.csie.nctu.edu.tw/pipermail/nctuns. The NCTUns forum can be accessed here at http://nsl10.csie.nctu.edu.tw/phpBB.
The NCTUns network simulator and
emulator was first released on
To see how people in the world are using NCTUns for their researches, you may search the “NCTUns” keyword in Google. To see the impact of NCTUns, you may search the “network simulator” keyword in Google. To read the many papers that use NCTUns to carry out research, you may search the “NCTUns”keyword in Google Scholar at http://scholar.google.com. Nowadays, many IEEE papers that use “NCTUns” are collected in IEEE Xplore digital library and cannot be accessed by Google. To see these papers, enter IEEE Xplore and use “NCTUns” as the keyword to search the full text of papers.
1. The NCTUns 6.0 is invited by IEEE WiVEC 2010 conference to demonstrate its simulation capabilities of advanced IEEE 802.11(p)/1609 WAVE wireless vehicular networks on May 16-17, 2010, Taipei, Taiwan.
2. The NCTUns 5.0 is invited by MDM 2009 conference (International Conference on Mobile Data Management – System, Services, and Middleware) to demonstrate its simulation capabilities of IEEE 802.11(p)/1609 WAVE wireless vehicular networks on May 18-20, 2009, Taipei, Taiwan.
3. The NCTUns 5.0 is invited by IEEE WiVEC 2008 conference to demonstrate its simulation capabilities of IEEE 802.11(p)/1609 WAVE wireless vehicular networks on September 21-22, 2008, Calgary, Canada.
4. The NCTUns 4.0 workshop was held on July 16-17, 2007. It attracted 195 professors, students, engineers, and researchers coming from 44 universities in Taiwan.
5. NCTUns 4.0 is exhibited at IEEE ICC
2007 conference (International Conference on Communication 2007), June
6. NCTUns 4.0 Beta is selected as a research exhibition by IEEE PIMRC 2006 conference (The 17th IEEE International Symposium on Personal, Indoor, and Mobile Radio Communications), Helsinki, Finland, September 11-14 2006.
3.0 was selected as a research demo by IEEE/Create-Net
conference (Conference on Testbeds and Research Infrastructures for the
Development of Networks and Communities),
2.0 was selected as a half-day tutorial by SPECT 2005 conference (2005 International
Symposium on Performance Evaluation of Computer and Telecommunication Systems,
sponsored by The Society for Modeling and Simulation International), held in
2.0 was selected as research demo by IEEE INFOCOM’05 conference held in
10. NCTUns 2.0 was selected as a half-day tutorial by MASCOTS 2004 conference (12th Annual Meeting of the IEEE / ACM International Symposium on Modeling, Analysis, and Simulation of Computer and Telecommunication Systems), Volendam, The Netherlands, October 4 –7, 2004.
11. IEEE Vehicular Technology Society, Taipei Chapter, selected NCTUns
2.0 as a full-day tutorial at its “Wireless Systems and Network Technologies”
12. The second NCTUns 1.0 workshop was held on December 12, 2003. It
attracted 120 professors, students, engineers, and researchers coming from 28
13. NCTUns 1.0 was selected as a research
demo by ACM MobiCom’03 held in
14. NCTUns 1.0 was reported in the “Software Tools for Networking” column of the IEEE Network Magazine in its July 2003 issue.
15. The first NCTUns 1.0 workshop was held on December 8, 2002. It
attracted 220 professors, students, engineers, and researchers coming from 26
16. NCTUns 1.0 was selected as a research demo by ACM MobiCom’02 held
1. International Games System CO. LTD. purchased two licenses for their commercial uses of NCTUns in the developments of performance evaluations of their on-line games products.
2. HITACHI SAS Europe purchased a license for their commercial uses of NCTUns in their wireless vehicular networks projects.
3. The Identification and Security Technology Center of Industry Technology Research Institute (ITRI), Taiwan purchased a license for their commercial uses of NCTUns in their video surveillance project.
4. NEC Europe Ltd. purchased a license for their commercial uses of NCTUns in their inter-vehicle communication projects.
5. The Information and Communication Research Laboratories of Industry Technology Research Institute (ITRI), Taiwan purchased a license for their commercial uses of NCTUns in their 4G+ wireless networks project.
6. The Land and Joint Division of the THALES group in Colombes France purchased a license for their commercial uses of NCTUns in their military-related projects.
7. Australian transformation and Innovation center (ATiC) run by ADI and THALES group purchased a license for their commercial uses of NCTUns in their military-related projects.
NCTUns is a high-fidelity and extensible network simulator and emulator capable
of simulating various protocols used in both wired and wireless IP networks. Its core technology is based
on the novel kernel re-entering methodology invented by Prof. S.Y. Wang [1, 2]
when he was pursuing his Ph.D. degree at
After obtaining his
Ph.D. degree from
The NCTUns network simulator and emulator has many useful features listed below:
· It can be easily used as an emulator. An external host in the real world can exchange packets (e.g., set up a TCP connection) with nodes (e.g., host, router, or mobile station) in a network simulated by NCTUns. Two external hosts in the real world can also exchange their packets via a network simulated by NCTUns. This feature is very useful as the function and performance of real-world devices can be tested under various simulated network conditions.
· It supports distributed emulation of a large network over multiple machines. When the emulated network has many nodes, many real-world applications need to run on these nodes, many real-world devices need to connect to the emulated network, or the amount of real-world packets exchanged among real-world devices over the emulated network is large, a single machine may not have enough CPU power and main memory to run the emulation in real time. In such a condition, NCTUns can partition the emulated network into several smaller parts and let each part be emulated by a NCTUns machine. The usage of a distributed emulation is totally automatic and the user won’t notice that the emulation is carried out over multiple machines.
· It supports seamless integration of emulation and simulation. A complicated network simulated by NCTUns can be seamlessly integrated with a real-life network. Real-life network traffic can pass through a complicated simulated network and interact with simulated network traffic.
· It directly uses the real-life Linux TCP/IP protocol stack to generate high-fidelity simulation results. By using a novel kernel re-entering simulation methodology, a real-life Linux kernel’s protocol stack is directly used to generate high-fidelity simulation results.
· It can run any real-life UNIX application program on a simulated node without any modification. Any real-life program (e.g., P2P BitTorrent or Java programs) can be run on a simulated host, router, mobile node, etc. to generate realistic network traffic. This capability also enables a researcher to evaluate the functionality and performance of a distributed application or system under various network conditions. Another important advantage of this feature is that application programs developed during simulation studies can be directly deployed and run on real-world UNIX machines after simulation studies are finished. This eliminates the time and effort required to port a simulation prototype to a real-world implementation if traditional network simulators were used.
· It can use any real-life UNIX network configuration and monitoring tools. For example, the UNIX route, ifconfig, netstat, tcpdump, traceroute commands can be run on a simulated network to configure or monitor the simulated network.
· Its setup and usage of a simulated network and application programs are exactly the same as those used in real-life IP networks. For example, each layer-3 interface has an IP address automatically assigned to it by the GUI and application programs directly use these IP addresses to communicate with each other. For this reason, any person who is familiar with real-life IP networks will easily learn and operate NCTUns in just a few minutes. For the same reason, NCTUns can be used as an educational tool to teach students how to configure and operate a real-life network.
· It simulates various important networks. The supported networks include Ethernet-based fixed Internet, IEEE 802.11(b) wireless LANs, mobile ad hoc (sensor) networks, GPRS cellular networks, optical networks (including both circuit-switching and busrt-switching networks), IEEE 802.11(b) dual-radio wireless mesh networks, IEEE 802.11(e) QoS wireless LANs, Tactical and active mobile ad hoc networks, 3dB beamwidth 60-degree and 90-degree steerable and directional antennas, IEEE 802.16(d) WiMAX wireless networks (including the PMP and mesh modes), DVB-RCS satellite networks, wireless vehicular networks for Intelligent Transportation Systems (including V2V and V2I), multi-interface mobile nodes for heterogeneous wireless networks, IEEE 802.16(e) mobile WiMAX networks, IEEE 802.11(p)/1609 WAVE wireless vehicular networks, various realistic wireless channel models, IEEE 802.16(j) transparent mode and non-transparent mode WiMAX networks, etc.
· It simulates various important protocols. For example, IEEE 802.3 CSMA/CD MAC, IEEE 802.11 (b) CSMA/CA MAC, IEEE 802.11(e) QoS MAC, IEEE 802.11(b) wireless mesh network routing protocol, IEEE 802.16(d)(e)( j) WiMAX wireless MAC and PHY, DVB-RCS satellite MAC and PHY, learning bridge protocol, spanning tree protocol, IP, Mobile IP, Diffserv (QoS), RIP, OSPF, UDP, TCP, RTP/RTCP/SDP, HTTP, FTP, Telnet, BitTorrent, etc.
· It finishes a network simulation case quickly. By combining the kernel re-entering methodology with the discrete-event simulation methodology, a simulation job can be finished quickly.
· It generates repeatable simulation results. If the user fixes the random number seed for a simulation case, the simulation results of a case are the same across different simulation runs even if there are some other activities (e.g., disk I/O) occurring on the simulation machine.
· It provides a highly-integrated and professional GUI environment. This GUI can help a user to quickly (1) draw network topologies, (2) configure the protocol modules used inside a node, (3) specify the moving paths of mobile nodes, (4) plot network performance graphs, (5) play back the animation of a logged packet transfer trace, etc. All of these operations can be easily, intuitively, and quickly done with the GUI.
· Its simulation engine adopts an open-system architecture and is open source. By using a set of module APIs provided by the simulation engine, a protocol developer can easily implement his (her) protocol and integrate it into the simulation engine. NCTUns uses a simple and easy-to-understand syntax to describe the settings and configurations of a simulation job. These descriptions are generated by the GUI and stored in a suite of files. Normally the GUI will automatically transfer these files to the simulation engine for execution. However, if a researcher wants to try his (her) novel device or network configurations that the current GUI does not support, he (she) can totally bypass the GUI and generate the suite of description files by himself (herself) using any text editor (or script program). The non-GUI-generated suite of files can then be manually fed to the simulation engine for execution.
· It supports remote and concurrent simulations. NCTUns adopts a distributed architecture. The GUI and simulation engine are separately implemented and use the client-server model to communicate. Therefore, a remote user using the GUI program can remotely submit his (her) simulation job to a server running the simulation engine. The server will run the submitted simulation job and later return the results back to the remote GUI program for analyses. This scheme can easily support the cluster computing model in which multiple simulation jobs are performed in parallel on different server machines. This can increase the total simulation throughput.
· It provides complete and high-quality documentations. The GUI user manual and the protocol developer manual provide detailed information about how to use NCTUns. The NCTUns package provides 83 example simulation cases and their demo video clips to help a user easily understand how to run up a simulation case.
· It is continuously supported, maintained, and improved. New functions and network types are continuously added to NCTUns to enhance its functions, speed, and capabilities.
At NCTU, Prof. S.Y. Wang and his students are working hard to continuously add more functionalities and features to NCTUns. They want to make it a high-quality software and would like to contribute it to the networking community.
THE NCTUNS NETWORK
SIMULATOR AND EMULATOR IS AN INTELLECTUAL PROPERTY OF THE NETWORK AND SYSTEM
LABORATORY (NSL), DEPARTMENT OF COMPUTER SCIENCE,
 S.Y. Wang and H.T. Kung, "A Simple Methodology
for Constructing Extensible and High-Fidelity TCP/IP Network Simulators,"
IEEE INFOCOM'99, March 21-25, 1999,
 S.Y. Wang and H.T. Kung, "A New Methodology for Easily Constructing Extensible and High-Fidelity TCP/IP Network Simulators," Computer Networks, Vol. 40, Issue 2, October 2002, pp. 257-278.
 NS-2 web site, available at http://www.isi.edu/nsnam/ns/
 OPNET Inc. web site, available at http://www.opnet.com/
Last update date: November 9, 2010