OPNET

TM

Modeler

CS 541 Advanced Networking Spring 2009

Outline     Getting Started Implement Custom Protocols Wireless Network Issues Debugging

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

Getting Started   Modeler Tutorials: [Help - Tutorials]  Go through all of them Module Tutorials  Creating a Wireless Network

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

OPNET Object Hierarchy Project Scenario Subnet Node Process C/C++ Code

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

Implement Custom Protocols     Create new process models Modify existing process models Create new packet formats Create/modify node models

MANET routing protocols ip_dispatch manet_mgr aodv_rte dsr_rte grp_rte …

Node Model: manet_station_adv

Process Model: manet_mgr

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

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

OPNET Wireless Suite     Pipeline Stages Node Mobility Antenna Pattern Terrain Effects

Understand Pipeline Stages  Pipeline – sequence of calculations    Point-to-Point Pipeline Models Bus Pipeline Models Radio Pipeline Models

Radio Pipeline Stages (Tx side) 1.

2.

3.

4.

5.

6.

Receiver Group Transmission Delay Link Closure Channel Match Tx Antenna Gain Propagation Delay

Radio Pipeline Stages (Rx side) 7.

8.

9.

10.

11.

12.

13.

14.

Rx Antenna Gain Received Power Interference Noise Background Noise Signal-to-Noise Ratio Bit Error Rate Error Allocation Error Correction

Default Pipeline Stages   Default stages   //models/std/links //models/std/wireless Default stage prefixes  dpt_* - default point-to-point   dbu_* - default bus dra_* - default radio

Customize Pipeline Stages    Write own .ps.c / .ps.cpp

Interface: void pipeline_stage (Packet *); Compilation  GUI – compile button   CMD – op_mko -type ps -m Generate .ps.o / .ps.obj

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

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

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

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

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

Random Waypoint   Node moves randomly from one waypoint to another Trajectory recording

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 ()

Antenna Modeling  Antenna Pattern Editor    Visualize pattern in 3D Specify gains (φ, θ) Normalization  Consult Naraj

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

Find and Install Terrain Data   DTED files  .dt0, .dt1, .dt2

USGS DEM files  .dem

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

Select a Propagation Model

Debugging     Strategy Select Kernel ODB C/C++ Debugger

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)

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

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

Make codes easy to debug      Prefer op_prg_odb_print () 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

Use a C/C++ Debugger      Compiling a process model generates a C/C++ file: .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

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

Questions?