OPNET TM Modeler

1. OPNETTM Modeler CS 541 Advanced Networking Spring 2009

2. Outline • Getting Started • Implement Custom Protocols • Wireless Network Issues • Debugging

3. Introduction • OPNET (www.opnet.com) • Discrete time simulation • Shipped with lots of models written in C • Platform: Windows/Linux • Programming Languages: C/C++ • GUI/command line simulation

4. Getting Started • Modeler Tutorials: [Help - Tutorials] • Go through all of them • Module Tutorials • Creating a Wireless Network

5. General Simulation Steps • Create network scenario(s) • Configure nodes • Create traffic • Configure/run simulation • Choose statistics • Configure/run simulation • View results (Export data)

6. OPNET Object Hierarchy

7. Communication Entities • Packets • Inter/intra node communication • Recursively organized • Structure vs. Physical Layout • ICI (Interface Control Information) • Within a node, between different layers/process models

8. Implement Custom Protocols • Create new process models • Modify existing process models • Create new packet formats • Create/modify node models

9. MANET routing protocols

10. Node Model: manet_station_adv

12. Process Model: manet_mgr

13. Create a New Process Model • Easier to copy and modify on exist model • Modifications: • The FSM (finite state machine) • State variables • Header/Function/… blocks, excecutives • External files (.h, .ex.c, .ex.cpp) • Add/modify attributes: model/global • Add/modify statistics: local/global

14. Add Support for New Model • Modify corresponding .h files, adding constants and enums • Declare pf_rte as child process of manet_mgr • Modify manet_mgr model: • Add attributes for pf_rte • Add code to create and invoke pf_rte process • Add code to dispatch packets to pf_rte • Use text search tools to help

15. OPNET Wireless Suite • Pipeline Stages • Node Mobility • Antenna Pattern • Terrain Effects

16. Understand Pipeline Stages • Pipeline – sequence of calculations • Point-to-Point Pipeline Models • Bus Pipeline Models • Radio Pipeline Models

17. Radio Pipeline Stages (Tx side) • Receiver Group • Transmission Delay • Link Closure • Channel Match • Tx Antenna Gain • Propagation Delay

18. Radio Pipeline Stages (Rx side) • Rx Antenna Gain • Received Power • Interference Noise • Background Noise • Signal-to-Noise Ratio • Bit Error Rate • Error Allocation • Error Correction

19. Default Pipeline Stages • Default stages • <opnet_dir>/<rel_dir>/models/std/links • <opnet_dir>/<rel_dir>/models/std/wireless • Default stage prefixes • dpt_* - default point-to-point • dbu_* - default bus • dra_* - default radio

20. Customize Pipeline Stages • Write own <name>.ps.c / <name>.ps.cpp • Interface: void pipeline_stage (Packet *); • Compilation • GUI – compile button • CMD – op_mko -type ps -m <name> • Generate <name>.ps.o / <name>.ps.obj

21. Assign Pipeline Stage to Module • In node model, set the attributes of radio transmitter or receiver objects • An attribute for each pipeline stage

22. Skip Pipeline Stages • To speed up simulations • Set the pipeline stage attribute to NONE • A fixed pre-determined value will be used.

23. Modeling Node Mobility • 4 methods: • Use trajectory files • Specify a “motion vector” via attributes • Random Waypoint Model • Update node position programmatically

24. Trajectory Files • Path of a mobile node during a simulation in a text file (.trj) • Absolute / relative positions

25. Motion Vector • Move along a great circle around the earth • Bearing / ground speed / ascent rate (advanced attributes)

26. Random Waypoint • Node moves randomly from one waypoint to another • Trajectoryrecording

27. Mobility KPs • op_ima_obj_pos_get () • op_ima_obj_pos_get_time () • op_ima_obj_pos_notification_register () • op_ima_obj_pos_query_proc_set () • op_ima_obj_pos_set_geocentric () • op_ima_obj_pos_set_geodetic ()

28. Antenna Modeling • Antenna Pattern Editor • Visualize pattern in 3D • Specify gains (φ, θ) • Normalization • Consult Naraj

29. Terrain Effects • Calculated in pipeline stage: Closure • Without TMM module: • LOS (Line Of Sight) with earth curve considered • With TMM module: • Free space • Longley-Rice • TIREM

30. Find and Install Terrain Data • DTED files • .dt0, .dt1, .dt2 • USGS DEM files • .dem

31. Display Elevation Maps • .el files, can be generated by OPNET using terrain data

32. Select a Propagation Model

33. Debugging • Strategy • Select Kernel • ODB • C/C++ Debugger

34. Debugging Strategy • Looking for clues: • Compiler warnings • DES Log • Error Log • OPNET Debugger (ODB) • Memory tracking • Animation and live statistics • Narrow down the problem • Time (simulation time, event#, packet#) • Location (node, module, process, code)

35. Simulation Kernels • Development Kernels • Allows ODB • OPNET Profiler • Detailed error messages • Slower simulation execution • Slightly higher memory usage • Optimized Kernels • Use for production

36. ODB Features • Graphical interface • Step through events • Breakpoints for specific • Event, time, module, process, packet • Trace Kernel Procedures (KPs) • Print out current status of simulation entities • Print out memory usage statistics • Pass control to and from a C/C++ debugger

37. Make codes easy to debug • Prefer op_prg_odb_print<major/minor> () over printf (). • Use op_sim_error () for errors. • Use FIN/FOUT/FRET in every function. • Helps OPNET to display the function call stack • Write traces and label them. • Write diagnostic blocks • Only invoked in ODB

38. Use a C/C++ Debugger • Compiling a process model generates a C/C++ file: <model_name>.pr.c or .cpp • Primary functions  unchanged • Executives / transitions  macros • Temporary variable block  local variables • State variables  fields of a struct • var_name  op_sv_ptr->var_name

39. Use a C/C++ Debugger with ODB • Run the simulation with ODB enabled • The simulation stops before the first event • Attach the C/C++ debugger to the simulation process • Set breakpoints in ODB or the C/C++ debugger • Continue from the C/C++ debugger • Continue in ODB

40. Questions?