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Simulation and Emulation with NCTUns

Simulation and Emulation with NCTUns. Professor Nelson Fonseca nfonseca@ic.unicamp.br. Outline. Introduction Simulation X Emulation Details Features Installation Utilization Examples Conclusions References. Introduction. Main features. Simulates and emulates network protocols

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Simulation and Emulation with NCTUns

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  1. Simulation and Emulation with NCTUns Professor Nelson Fonseca nfonseca@ic.unicamp.br

  2. NCTUns - Professor Nelson Fonseca Outline • Introduction • Simulation X Emulation • Details • Features • Installation • Utilization • Examples • Conclusions • References

  3. NCTUns - Professor Nelson Fonseca Introduction

  4. NCTUns - Professor Nelson Fonseca Main features • Simulates and emulates network protocols • Open source • Modified Linux kernel • GUI and shell commands • Client-server model to allow communication between simulation/emulation engine and interface • Since 2002 (version 1.0)‏ • Version 5.0 released in 2008

  5. NCTUns - Professor Nelson Fonseca Comparing with traditional simulators • Uses native Linux TCP/IP stack • Interacts with real devices in virtual networks • Allows experiments with real applications • There is no need to change the real applications • Allows remote simulations and concurrent simulations • Easy to create simulation servers • Can take advantage of multiple cores/processors

  6. NCTUns - Professor Nelson Fonseca Simulation X Emulation

  7. NCTUns - Professor Nelson Fonseca Simulation • Ideal to create several different scenarios • Ideal when there isn't available testbeds • Results not always the same as the reality because the applications are not the same • Example: applications in the ns-2 simulator need to be rewritten to run inside the simulator (problem recently solved with ns-3)‏

  8. NCTUns - Professor Nelson Fonseca Emulation • Uses real applications and network devices • More realistic scenarios and more trustable results • Can combine virtual and real devices/protocols • Example: how will be the behaviour of a real application over a new transport protocol? • Less flexible than simulations • the characteristics of the emulated links are limited to the characteristics of the real links

  9. NCTUns - Professor Nelson Fonseca NCTUns • Simulator and emulator • It is possible to use as a conventional simulator • It is possible to evaluate new real applications over different network configurations • It is possible to evaluate new protocols with different real applications • It is possible to capture the generated traffic and use it as input to packet analysers like wireshark

  10. NCTUns - Professor Nelson Fonseca Details

  11. NCTUns - Professor Nelson Fonseca Features (1)‏ • Support to several protocols is already included: • IEEE 802.3, IEEE 802.11, IEEE 802.16, Learning bridge protocol, Spanning tree protocol, ... • IP, Mobile IP, RIP, OSPF, OBS, GPRS, ... • TCP, UDP, SDP, ... • HTTP, FTP, telnet, ... (+ any real application)‏ • Some specific applications included: • stcp/rtcp - Greedy TCP traffic • ttcp - Greedy TCP/UDP trafic • stg/rtg - Greedy TCP/UDP traffic, trace driven, self-similar traffic, on-off, constant-bit-rate, and various packet streams.

  12. NCTUns - Professor Nelson Fonseca Features (2)‏ • Support to several links and devices is already included • PPP link, ethernet link, ... • Host, hub, switch, router, ... • QoS Diffserv boundary/interior routers • Optical burst/circuit switch • External host, external router (emulation)‏

  13. NCTUns - Professor Nelson Fonseca Features (3)‏ • Creates virtual interfaces to simulate the devices of the scenario • Inspiration from loopback interface • Utilizes IP address 1.0.0.0 • During the simulation it is possible to “see” the interfaces with the commands /sbin/ifconfig or /sbin/route • Interfaces named tun0, tun1, tun2, ...

  14. NCTUns - Professor Nelson Fonseca Features (4)‏ • How loopback works? (Host 1 and Host 2 are the same host)‏

  15. NCTUns - Professor Nelson Fonseca Features (5)‏ • Kernel re-entering methodology

  16. NCTUns - Professor Nelson Fonseca Installation (1)‏ • Download from:http://nsl10.csie.nctu.edu.tw/products/nctuns/download/download.php • Software requirements: • Operating system Fedora Linux 10.0 • gcc and g++ compiler • X window system • Tcl • rsh server and rlogin • SELINUX disabled • Firewall disabled • root privileges

  17. NCTUns - Professor Nelson Fonseca Installation (2)‏ • Hardware requirements: • RAM memory 256 MB • Pentium 1.6GHz processor • At least 200MB free disk space • Multi-core processors are supported

  18. NCTUns - Professor Nelson Fonseca Installation (3)‏ • Installation procedure • Uncompress the downloaded .tar.gz file • Run ./install.sh • Reboot • Select one of the two new kernels: • NCTUns • NCTUns (ELP) – If you want to use more than one core/processor

  19. NCTUns - Professor Nelson Fonseca Utilization (1)‏ • Basic components (binaries)‏ • nctunsclient – GUI interface between user and system • nctuns – shell interface between user and system • nctunsse – NCTUns core • dispatcher – Manage the simulation requests. Can control multiple coordinators running in different machines • coordinator – Receives the simulation from the dispatcher and forward it to the nctunsse

  20. NCTUns - Professor Nelson Fonseca Utilization (2)‏ • Each simulation server = kernel modifications + nctunsse + protocol modules + coordinator

  21. NCTUns - Professor Nelson Fonseca Utilization (3)‏ • Folders organization • tools = executable programs of various applications and tools pre-installed by NCTUns 5.0 • bin = executable programs of the GUI program, dispatcher, coordinator, and the simulation engine • etc = configuration files needed by the dispatcher and coordinator programs • BMP = icon bmp files uses by the GUI program • lib = libraries used by the simulation engine

  22. NCTUns - Professor Nelson Fonseca Utilization (4)‏ • Execution order • dispatcher • Waits client connection via TCP port 9800 • Waits coordinator connection via TCP port 9810 • coordinator • Connects to dispatcher • nctunsclient or nctuns • Connects to dispatcher to send the scenario and waits the end of the simulation. The nctunsse is started by the coordinator

  23. NCTUns - Professor Nelson Fonseca Utilization (5)‏ • How to use the GUI?

  24. NCTUns - Professor Nelson Fonseca Utilization (6)‏ • Draw topology

  25. NCTUns - Professor Nelson Fonseca Utilization (7)‏

  26. NCTUns - Professor Nelson Fonseca Utilization (8)‏ • Edit property

  27. NCTUns - Professor Nelson Fonseca Utilization (9)‏

  28. NCTUns - Professor Nelson Fonseca Utilization (10)‏ • Run simulation

  29. NCTUns - Professor Nelson Fonseca Utilization (11)‏

  30. NCTUns - Professor Nelson Fonseca Utilization (12)‏

  31. NCTUns - Professor Nelson Fonseca Utilization (13)‏ • Playback

  32. NCTUns - Professor Nelson Fonseca Utilization (14)‏

  33. NCTUns - Professor Nelson Fonseca Utilization (15)‏

  34. NCTUns - Professor Nelson Fonseca Utilization (16)‏

  35. NCTUns - Professor Nelson Fonseca Utilization (17)‏ • Main simulation files • .emu: external routing table (needed to emulation)‏ • .ndt: nodes identification • .tfc: list of commands to be executed • .srt-l: internal routing table (tun[0-9]* devices)‏ • .tcl: scenario details • One example of each file is available athttp://www.lrc.ic.unicamp.br/~daniel/trento/nctuns/

  36. NCTUns - Professor Nelson Fonseca Utilization (18)‏ • To run without the GUI • Create the basic scenario from the GUI (It is easier)‏ • Make the necessary changes in the files • Run nctuns <file.tcl> • <file.tcl> is generated by the GUI • Wait for the results

  37. NCTUns - Professor Nelson Fonseca Examples (1)‏ • Scenario 1 • Network topology: 2 hosts connected by an ethernet link • Protocols: TCP and UDP • Applications: rtcp/stcp • Devices:

  38. NCTUns - Professor Nelson Fonseca Examples (2)‏ • Scenario 1 – Applications configuration • To simulate data transfer between host 1 (1.0.1.1) and hosts 2 (1.0.1.2) via TCP using stcp and rtcp • Host 1: stcp -p 8000 1.0.1.2 • Sending TCP segments to 1.0.1.2 at port 8000 • Host 2: rtcp -p 8000 • Receiving TCP segments from port 8000

  39. NCTUns - Professor Nelson Fonseca Examples (3)‏

  40. NCTUns - Professor Nelson Fonseca Examples (4)‏ • Scenario 2 • To simulate data transfer between host 1 (1.0.1.1) and host 2 (1.0.1.2) via UDP using stg and rtg • Host 1: stg -u 1000 50 -m 50 50 -p 8000 1.0.1.2 • Sending UDP datagrams to 1.0.1.2 at port 8000. Transmission rate limited to 50Mbps and packet size equal to 1000 bytes. • Host 2: rtg -u -p 8000 • Receiving UDP datagrams from port 8000

  41. NCTUns - Professor Nelson Fonseca Conclusions

  42. NCTUns - Professor Nelson Fonseca Conclusions • Joins simulation and emulation in one tool • Intuitive and simple GUI • Good if there is a few number of scenarios • Hard to manage if there is a large number of scenarios • Good documentation • Several demo videos at official website

  43. NCTUns - Professor Nelson Fonseca References • http://nsl10.csie.nctu.edu.tw/ • Official website • http://nsl.csie.nctu.edu.tw/nctuns.html • List of related papers • http://nsl10.csie.nctu.edu.tw/support/documentation/GUIManual.pdf • GUI user manual • http://nsl10.csie.nctu.edu.tw/support/documentation/DeveloperManual.pdf • Developer manual • http://nsl10.csie.nctu.edu.tw/support/documentation/DemoVideos/ • Videos of NCTUns in action

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