1. HyunJun Choi Aug 27, 2004 OPNET Simulator HyunJun Choi Aug 27, 2004 Informational Communication University

2. HyunJun Choi Aug 27, 2004 Contents Modeling Overview Process domain Node domain Project domain

3. HyunJun Choi Aug 27, 2004 What is OPNET? A powerful network simulation tool –comprehensive development environment for modeling of communication networks and distributed systems –Accuracy and easy-of-use for network planner System requirements –Visual studio 6.0 References –www.opnet.comwww.opnet.com –www.simus.netwww.simus.net

4. HyunJun Choi Aug 27, 2004 Modeling Overview

5. HyunJun Choi Aug 27, 2004 Backgrounds Object orientation –OPNET Consists of objects, each with configurable sets of attribute –Objects Belong to classes Specialized in communication networks and information systems Graphical specification Flexibility to develop detailed custom models –OPNET provides a flexible, high-level programming language with extensive support Automatic generation of simulations – Automatically compiled with C programming language

6. HyunJun Choi Aug 27, 2004 Typical Applications of OPNET Standards-based LAN and WAN performance modeling Internetworking planning Research and development in communications architectures and protocols Distributed sensor and control networks Mobil packet radio networks Satellite networks

7. HyunJun Choi Aug 27, 2004 OPNET simulator Architecture Initial Specification Analysis Data Collection and Simulation Re-Specification Simulation Project Cycle

8. HyunJun Choi Aug 27, 2004 Specification Editors Project Editor –Specify network topology and configure nodes and links Node Editor –Create models of nodes by specifying internal structure and capabilities –Combine modules Process Editor –Develop models of decision-making processes representing protocols, algorithms, resource managers, operation systems, etc. Link Editor –Create, edit, and view link models Packet Format Editor –Specify packet format, defining the order, data type, and size of fields contained within the packet ICI Editor –Create, edit, and view interface control information formats

9. HyunJun Choi Aug 27, 2004 Specification Editors (cont’d) PDF Editor –Create, edit, and view PDF Probe Editor –Identify sources of statistics and animation that are to be collected during a simulation –Done before execution Simulation Tool –Design and run sequences of simulations, each potentially configured with different inputs and/or outputs Analysis Tool –Plot and process numerical data generated by simulations

10. HyunJun Choi Aug 27, 2004 Graphical Editors for networks, node, and process models

11. HyunJun Choi Aug 27, 2004 Modeling domains DomainEditorModeling Focus NetworkProject Network topology described in terms of subnetworks, nodes, links, and geographical context. Node Node internal architecture described in terms of functional elements and data flow between them. Process Behavior of process (protocols, algorithms, applications), specified using finite state machines and extended high-level languages

12. HyunJun Choi Aug 27, 2004 Network domain example

13. HyunJun Choi Aug 27, 2004 Node domain example

14. HyunJun Choi Aug 27, 2004 Process domain example

15. HyunJun Choi Aug 27, 2004 Simulation Output Data Types Output vectors –Most common results type –Consist of dependent and independent variables, pairs of real values Output Scalars –Individual values Ex) Averages, Probabilities, peak value, etc. –Ex) Throughput vs. Offered Load

16. HyunJun Choi Aug 27, 2004 OPNET model hierarchy

17. HyunJun Choi Aug 27, 2004 Process domain

18. HyunJun Choi Aug 27, 2004 Process Model Example Sink Process

19. HyunJun Choi Aug 27, 2004 Interrupt-Driven Execution Process are driven by events –Internally or externally interrupted

20. HyunJun Choi Aug 27, 2004 Process Hierarchy Root process – Child process –Call KP Op_pro_create()

21. HyunJun Choi Aug 27, 2004 Interrupt Steering Example

22. HyunJun Choi Aug 27, 2004 Local Process Resources Input and Output Streams –Packet streams are objects in Node Editor and used to connect modules together –Packet streams connect source with destination modules which are called output and input streams Input stream to receiver process –op_intrpt_stream(), op_pk_get(), op_strm_pksize(),and etc. Output stream from sender process –Op_pk_send(), op_pk_send_delayed(), op_pk_send_forced(),and ect.

23. HyunJun Choi Aug 27, 2004 Graphical expression of Streams

24. HyunJun Choi Aug 27, 2004 Graphical expression of Streams (Cont’d) Recall this picture!

25. HyunJun Choi Aug 27, 2004 State Transition diagram Proto-C models consist of two basic components –States and Transitions A process has two executives –Enter executive and Exit executive Forced and Unforced States –Forced State (Green) Proceeds without any event –Unforced State (Red) Pauses between enter and exit executives Waits for interrupt to break Blocked Enter Exit

26. HyunJun Choi Aug 27, 2004 Execution Flow through Combination of Unforced and Forced States Invocation starts at top of exit executives of unforced states Invocation starts at bottom of Enter executives of unforced states

27. HyunJun Choi Aug 27, 2004 State Transition diagram (Cont’d)

28. HyunJun Choi Aug 27, 2004 Initial state & transitions Initial state –Must be designed in each process model –Occur only once Transitions –Movement of a process from state to state and conditions under which such changes may take places (condition)/Executive

29. HyunJun Choi Aug 27, 2004 Transition Examples

30. HyunJun Choi Aug 27, 2004 Transition Examples (Cont’d)

31. HyunJun Choi Aug 27, 2004 Macro Definitions within Process Model Header Block

32. HyunJun Choi Aug 27, 2004 Variables State variable –Used to represent the information accumulated and retained by a process –Require a memory allocation of corresponding size that will last as long as the process exists Temporary variable –Used to store information that doesn’t require persistency –Doesn’t require additional memory Global variable –Used to provide a means for multiple processes in different modules

33. HyunJun Choi Aug 27, 2004 Attributes Specify Characteristics of a process –Ex) time out duration, window size, max number of retransmission, etc.

34. HyunJun Choi Aug 27, 2004 Attributes usage example

35. HyunJun Choi Aug 27, 2004 Node Domain

36. HyunJun Choi Aug 27, 2004 Node modeler example Ethernet Lan

37. HyunJun Choi Aug 27, 2004 Typical Node Models Work station –Generate and receive transfers of files or sparse packets and manage several concurrent network connections Packet switch –Supports large numbers of incoming and outgoing data links and performs packet routing at high speeds Satellite terminal –Generates and receives packets according to a CA protocol Remote data sensor –Acts as a simple source of packets, usually transmitting them in bursts

38. HyunJun Choi Aug 27, 2004 Module definition Processor modules –Primary general-purpose building blocks of node models –Can be specified by process model attribute –Used to perform general processing of data packets Queue modules –Provide superset of the functionality of processor modules –Are related to memories

39. HyunJun Choi Aug 27, 2004 Module definition (Cont’d) Transmitter modules –Serve as the outbound interface between packet streams in side a node and communication links outside node

40. HyunJun Choi Aug 27, 2004 Module definition (Cont’d) Receiver modules –Serve as the inbound interface between communication links outside a node and packet streams inside the node

41. HyunJun Choi Aug 27, 2004 Connection definition Packet streams –Support the flow of data packets between modules –Three methods for transferring a packet and notifying arrivals Scheduled arrival –Is scheduled of the destination module –Occurs after all other events Forced arrival –Occurs immediately Quiet arrival –No stream interrupt occurs at all

42. HyunJun Choi Aug 27, 2004 Connection definition (Cont’d) Statistic wire –Unlike packet streams, it convey individual values –Individual values are used as an interface where the source module and can share certain values with destination module –Each module within a node has a set of local input and output statistics

43. HyunJun Choi Aug 27, 2004 Connection definition (Cont’d) Logical Associations –Do not actually carry data between modules –Do not exit during simulation, but used purely as specification devices –Used to interpret structure

44. HyunJun Choi Aug 27, 2004 OSI/OPNET layering analogy

45. HyunJun Choi Aug 27, 2004 Network Domain

46. HyunJun Choi Aug 27, 2004 Project modeler example Office network

47. HyunJun Choi Aug 27, 2004 Network domain Define the overall scope of a system to be simulated Size and scope of the networks modeled can range simple to complex

48. HyunJun Choi Aug 27, 2004 Network objects Subnetworks –Provide a powerful mechanism to manipulate complex networks structures and to break down the system’s complexity through abstractions –Have Fixed, mobile, satellite types

49. HyunJun Choi Aug 27, 2004 Network objects (Cont’d) Communication nodes –Exits within a subnetwork and represents a network device with a wide range of possible capabilities –Determined by node models –Have fixed, mobile, and satellite types

50. HyunJun Choi Aug 27, 2004 Network objects (Cont’d) Communication links –Allow communication of information between nodes in the form of structured message called packets –Simplex, duplex point to point, bus and taps

51. HyunJun Choi Aug 27, 2004 Modeling node and subnetwork movement Trajectories –Vector based Direction and velocity – segment based Time and three dimension (x, y and altitude)

52. HyunJun Choi Aug 27, 2004 Simulation time -packet switching-