Communication Network Simulations Using OPNET

Juha-Pekka Mäkelä

juha.makela AT ee.oulu.fi

521365S Tietoliikenteen simuloinnit ja työkalut

20.4.2010 klo 12.15

TS407

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Network simulations

• Simulations are used for

– Application

– Equipment

– Protocol (algorithm)

– Network security

functionality verification and implementation comparison

• Modeling of a real communication network

2

Things that are simulated

• Packet transmission.

– Capacity

• Packet formation.

– Packet length and distribution

• Terminal entering and exiting networks

• Communication link setup between terminals

• Mobility

• Effect of disturbance of other transmissions

3

Results

• End to end delay

• Throughput

• Packet loss

• Congestion and lost connections

• Traffic distribution

• Network utilization

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Throughput

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

0.2

0

0.00

78125

0.01

5625

0.03

125

0.06

25

0.12

50.

25 0.5 1 2 4

G

S

ALOHA

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End to end delay

G

de

lay

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Ad hoc networks

• MAC and Routing

• MAC

– TDMA, FDMA, CDMA, OFDMA, CSMA

• QoS

• Routing

– Proactive vs. reactive

– Scalability

• Routing overhead

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Sensor networks

• Straight implementation

– Large amoung of sensors with low cost

– Embedded programming

• Only very big networks must be simulated.

• Enegry efficiency

• Protocol simplicity

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Network simulators

• OPNET (www.opnet.com)

• NS2 (http://www.isi.edu/nsnam/ns/)

• OMNeT++ (http://www.omnetpp.org/)

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OPNET

• Event based discrete time simulator.

• Packet level simulations

• Developped for wireline simulations

• Currently also supports wireless system simulations

– Radio channel modelled accurately

• For R&D

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Modelling

•Network

•Sub nets, topologies, geocraphical modelling, mobility

•Node

•Routers, servers, clients, mobile terminals etc.

•Process

•Protocols (TCP/IP), data generation, algorithms, etc

External processeing possible (Matlab)

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Tools in OPNET• Network model editor

• Node model editor

• Process model editor

• Source code editing environment

• Antenna pattern editor

• Modulation curve editor (SNR –BER behavior)

• Packet format editor

• Analysis configuration tool

• Simulation tool

• ICI editor (Interface Control Information)

• Probe model tool (organization of result collection)

• Link model editor (properties of fixed link models)

• Path model editor (for routing and modeling virtual circuits)

• Demand model editor (wide scale application modeling)

• OPNET Animation viewer

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Network modeling

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Network modeling (2)

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Node modeling

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• Node structure

• OSI –like presentation

• One node can also be a sub-network

Node modeling (2)

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Process modeling

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Process modeling (2)

• Process models determine the functionality of the node model

• State machines

• Conditional transitions from state to another determined by external events

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Process modeling (3)

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Process modeling (4)Editor to help C/C++ code writing.

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Simulation toolParametrized

simulations

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Simulation tool (2)

• Simulations as a function of time

• Not enough for determining the full statistics of a phenomenon

• Several simulations needed with different seeds

• Typical results are averaged combinations of different iterations.

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Analyze tool

• Tool for inspection of results

• Published results can be done with Matlab where there are more possibilities for editing the results

• Numerical values of the simulation results also available

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Physical link (Radio)

• Physical link is presented with a connection where all the issues present in the physical layer are described.

• When a packet travels inside the simulation, the effect of all the states of the PHY layer is calculated

• The effect of other users also taken into account.

• All the states are presented with editable C/C++ code

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Physical link (Radio)(2)

• Used connection components are determined by the transceiver attributes.

• The attributes can be altered during the simulation

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Physical link (Radio)(3)

BER for a BPSK moddulation

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Antenna modeling

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Packet editor

• Packet editor can be used for describing the transmission packets used for the simulation

• Length and content can be determined according to one’s needs

• Data transmission among the simulation entities.

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OPNET productsNetwork R&D

– OPNET Modeler –The main simulation & development tool+ Wireless suite and Defense additions

Capacity management

– IT Guru (network and system capacity planning for enterprises)

– SP Guru (network planning and engineering for service providers)

Network operations

– IT Sentinel (network audit, security, and policy compliance for enterprises )

– SP Sentinel (network audit, security, and policy compliance for service providers)

– IT and ST Netcop (unified network views and situational awareness)

Application performance management

– ACE Analyst (analytics for networked applications)

– ACE Live (enduser experience monitoring & realtime network analytics)

– SLA Commander (application service level monitoring)

– OPNET Panorama (realtime application monitoring and analytics)29

Options for OPNET Modeler

• UMTS (WCDMA)

• WiMAX (802.162004, 802.16e2005)

• DOCSIS (Data Over Cable Service Interface Specification)

• IPv6 + Mobile IPv6

• MPLS (MultiProtocol Label Switching)

• PNNI (Private NetworkNetwork Interface)

• Terrain Modeling

• TIREM (propagation modeling calculation)

• Satellite Capability (dozens of models for satellite systems)

• Joint Communications Simulation System (JCSS) (Military orientated models)

• Vendor Devices (Dozens of vendor specific devices)

• Integration with 3rd Party Products (several modules)

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Summary

• OPNET is an event based (discrete time) communication network simulator software

• Networks modeled in three levels; network , node, process.

• Modeling can be done with the desired accuracy.

• External processing can be used.

• Vast number of additional features and tools to ease the problem solving

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References

• OPNET Modeler + Wireless (version 16.0 (14.0))

• OPNET (versions 16.0 (14.0)) Documentation

• OPNET Technologies, Inc. WWW page, http://www.opnet.com

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