Lab 1. Design and Deployment of Optical Access Network Device

1. Lab 1. Design and Deployment of Optical Access Network Device Chuan-Ching Sue DCNLAB, CSIE NCKU suecc@mail.ncku.edu.tw

2. Outline • Architecture of EPON • OMNeT++ • Deployment of EPON • Property of Network Traffic • Wireshark and Experimental Procedure • Conclusion

3. Architecture of EPON

4. Ethernet Passive Optical Networks • EPON is a point-to-multipoint network. • All transmissions in a PON are performed between an optical line terminal (OLT) and optical network units (ONUs).

5. Downstream Direction • In the downstream direction (from the OLT to ONUs) • A PON is a point-to-multipoint network. • Ethernet packets transmitted by the OLT pass through a 1 × N passive splitter and reach each ONU.

6. Upstream Direction • In the upstream direction • A PON is a multipoint-to-point network: multiple ONUs transmit all toward the OLT.

7. Upstream Direction (Cont’d) • In the upstream direction • Due to the directional properties of a passive optical combiner, data packets from any ONU will reach only the OLT, and not other ONUs. • EPON needs to employ some arbitration mechanism to avoid data collisions and fairly share the channel capacity among ONUs.

8. OLT • The OLT resides in the CO and connects the optical access network to the metropolitan-area network or wide-area network (WAN), also known as the backbone or long-haul network. • The OLT typically has the entire downstream bandwidth available to it at all times.

9. ONU • The ONU is located either at the end-user location (FTTH and FTTB) or at the curb, resulting in fiber-to-the-curb architecture. • To avoid data collisions, each ONU must transmit in its own transmission window (timeslot). • An ONU should buffer frames received from a subscriber until its timeslot arrives.

10. Splitter/Combiner • The passive splitter/combiner is more inexpensive than the active curb. • The directional properties of a passive splitter/combiner are such that an ONU transmission cannot be detected by other ONUs.

11. Multi-Point Control Protocol • To support dynamic capacity allocation, the IEEE 802.3ah task force has developed the multi-point control protocol[1]. • The MPCP is not concerned with a specific DBA algorithm. • It is a supporting mechanism that facilitates implementation of various bandwidth allocation schemes in EPON.

12. Multi-Point Control Protocol (Cont’d) • This behavior necessitated the following MPCP modes of operation: • Bandwidth assignment mode • To sustain communication between OLT and ONUs, the MPCP should provide periodic granting for each ONU. • Autodiscovery mode • To discover newly activated ONUs, the MPCP should initiate the discovery procedure periodically.

13. Bandwidth Assignment Mode • The bandwidth assignment mechanism relies on GATE and REPORT in IEEE 802.3ah. Both GATE and REPORT messages are MAC control frames. • GATE message is sent from the OLT to an individual ONU and is used to assign a transmission timeslot to this ONU. A timeslot is identified by a pair of values {startTime, length}.

14. Bandwidth Assignment Mode (Cont’d) • A REPORT message is a feedback mechanism used by an ONU to convey its local conditions (such as buffer occupancy) to the OLT to help the OLT make intelligent allocation decisions.

15. Processes in Bandwidth Assignment

16. OMNeT++

17. OMNeT++ • OMNeT++ is an object-oriented modular discrete event network simulation framework. • Current release: OMNet++ 4.1, June 2010 • OMNeT++ simulations can be run under various user interfaces. • Graphical • highly useful for demonstration and debugging purposes • Command-line user interfaces • best for batch execution.

18. Supported Platforms • OMNeT++ has been tested and is supported on the following operating systems: • Windows 7, Vista, XP • Mac OS X 10.5 and 10.6 • Linux distributions

19. Installation • The following installation guide consist of • Install in Windows series (7, Vista, XP) for personal use • Install in a Linux server for multiple user • Users can login server by “Remote Desktop Connection” in Windows and execute simulation concurrently.

20. Installation in Windows • Download the OMNeT++ source code from http://www.omnetpp.org • Make sure you select the Windows-specific archive, named omnetpp-4.1-src-windows.zip. • Copy the OMNeT++ archive to the directory where you want to install it. • Choose a directory whose full path does not contain any space. • Extract the zip file.

21. Installation in Windows (Cont’d) • Double click to launch mingwenv.cmd in the omnetpp-4.1 directory. • Then enter the following commands: • ./configure • make • The installation is finished!

22. Launch The IDE • After installation, you should be able to start the IDE by typing: • omnetpp

23. Installation in Linux server • To support multiple user for simulation, below softwares are required • Remote desktop • VNC • Xrdp • Simulator • OMNeT++ • We take Linux Centos 6 as an example in installation.

24. Setup Remote Desktop • Install VNC server • yum install tigervnc-server • Download xrdp-0.5.0-0.13.el6.i686.rpm from • http://rpm.pbone.net/index.php3/stat/4/idpl/15295587/dir/fedora_6/com/xrdp-0.5.0-0.13.el6.i686.rpm.html • Install xrdp • rpm –ivh xrdp-0.5.0-0.13.el6.i686.rpm • Launch the xrdp server • /etc/init.d/xrdp start

25. Open port 3389 of firewall • Open the port 3389 of the firewall to allow client connect to server by xrdp.

26. Install OMNeT++: Setup PATH • Create a file named “omnetpp.sh” in /etc/profile.dand add below command into omnetpp.sh

27. Check PATH • Reboot system and check PATH by • echo $PATH • echo $TCL_LIBRARY

28. Install OMNeT++: Install Dependency Package • The OMNeT++ require many packages,they can be installed by yum. • Open a terminal and input a command • yum install gcc-c++tcltcl-develtktk-devel libxml2 java-1.6.0-openjdk bison flex perl make zlib-devel

29. Install OMNeT++: Compile OMNeT++ • Download omnetpp-4.1-src.tgz from [3]. Notice that it can not be confuse by the omnetpp-4.1-src-windows.zip which is for windows platform. • Decompress omnetpp-4.1-src.tgz into /usr/local/src • Go to /usr/local/src/omnetpp-4.1 • Command in X11 (graphical user interface) • ./configure. • make

30. Install OMNeT++: Launch OMNeT++ • After make is finish, command “omnetpp” to launch OMNeT++

31. Create User Account • The user account can be created by the GUI or some scripts. Both will be fine. • The xrdp server should be reload after creating every user account. • /etc/init.d/xrdp reload

32. Login Server by GUI • Launch “Remote Desktop Connection”(遠端桌面連線) and enter the IP address of Linux server. • Use the username and password on the Linux server to login the server.

33. Create & Setup Workspace • Since the OMNeT++ was installed in the /usr/local/src/omnetpp-4.1 which is a read only space. The workspace folder should be created in the user’s home directory. • Create a personal workspace folder by • mkdir –p ~/omnetpp/samples • Enter “omnetpp” to launch OMNeT++ • Workspace: /home/{username}/omnetpp/samples • Select “Use this as the default and do not ask again”

34. Create & Setup Workspace: Example

35. OMNeT++ Setup Finish • After the workspace setting, the setup for OMNeT++ is finish.

36. Deployment of EPON

37. New a OMNeT++ Project • After the installation was finished, we can deploy the EPON system in the OMNeT++ simulator. • Click File -> New -> OMNeT++ Project…

38. New a OMNeT++ Project (Cont’d) • Enter a project name in the blank. In this slides, we take “EPON” as example. • Press Next > to go to the next configuration.

39. Initial Contents • Select a template of the new project. Here we choose the “Empty project with ‘src’ and ‘simulations’ folders” one as example. • Press “Finish” and create the new project.

40. The Created Project • The new project includes • src folder • Simulations folder • Makefiles (Makefile and Makefile.vc )

41. Function of The Separated Folders • src folder • This folder contain all source code files including C++ header file (*.h), C++ source file (*.cc) and network description file (*.ned). • simulation folder • This folder contain network only.

42. New Network Description File • Right click the src folder and choose “New -> Network Description File (NED) ” to create a new NED file.

43. New Network Description File (Cont’d) • Key in the file name and press the “Next” button. In this example, the file name is “device.ned”.

44. New Network Description File (Cont’d) • Choose “Empty NED file” and click “Finish” to create the device.ned file.

45. The User Module • The user module should contain • Number of source • Set default number to 64 ONUs • Hurst parameter • Set default value of Hurst parameter is 0.8[3] • Offered load • A gate to ONU

46. The ONU Module • The ONU module should contain • The buffer size for data packet • The default value is 10 MBytes • A gate from user • A gate to splitter • A gate from splitter

47. The Splitter Module • The splitter module should contain • An array of gate from user • An array of gate to user • A gate to OLT • A gate from OLT

48. The OLT Module • The OLT module should contain • A gate to splitter • A gate from splitter

49. New an “EPON” Network • To link the above modules into an EPON, we need a network to connect those modules. • New a epon.ned file in the simulation folder and input below description.

50. New an “EPON” Network (Cont’d) • Since the maximum distance between the OLT and the ONU is 20 km, the propagation delay from OLT to ONU is 100 microseconds.