Tuesday, February 25, 2014

Configuring Topolgies in OPNET

Every network element in OPNET is represented as an Object.
Properties of network elements are specified by object attributes.
Properties for these network elements are usually pre-configured with default values.

Basic Attributes represent a single property of the network element, e.g. IP address.
Compound Attributes group basic attributes based on some common characteristics, e.g. TCP Parameters consists several basic attributes such as receive buffer size, MSS, max ACK delay etc.

The network element's pop-up menu allows to change the attributes values.

In Edit Attributes Dialog Box, the Attribute Name column list the compound attributes as tree view.
In edit attributes dialog, checking Apply selected objects checkbox will apply attribute changes to all objects that have been selected.

Some objects may contain multiple instances of the same attribute, e.g. server may support multiple application services, each of which may be configured separately; in such situation an attribute may have a child called Number of Rows.

By default, value of Number of Rows for most attributes is 0.

OPNET uses the model hierarchy. This hierarchy contains levels as:
  • Process Level (Process Editor)
  • Node Level (Node Editor)
  • Network Level (Project Editor)
  • Simulation Level
  • Process Editor enables to develop and compile process models, process model allows to model individual network protocols and technologies.
  • Node Editor defines individual network devices which are modeled as one or more modules; every model has an associated process model which defines the operation of module.
  • Project Editor allows to organize node models/network devices into a network topology and change attributes of the objects in the created topology.
  • Other editors can be Link Editor, Path Editor, Demand Editor, Packet Format Editor etc.
The attribute values can be promoted to the node, to the network, and even to the simulation level.

To promote attribute to higher level, in Edit Attributes dialog right click on value of attribute and Select Promote Attribute to Higher Level.

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