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Modeling Node Architecture

 

The Node Model defines the architecture of network elements (hosts or routers) within the Network Model and shows the interralation of the protocol layers (Process Model). The picture on the right shows the action button panel of the Node model.  We have created three types of nodes: hosts, gateways, or routers. Although the structures of a router and a gateway are different, a Gateway has MAC and ARP layers under IP but a Router only has a dummy layer. However, they do share the same process code.

Right-click the processes in the node model or lines between processes to edit their attributes.
 

In the process attributes dialog, you can define a process name, process model and simulation control. NOTE: if you set "begsim intrpt" to "disabled", the process will never start to run during the simulation.

 

You can set the name, source and destination of the stream and interrupt mothod in the stream attributes dialog.  There are three kinds of relationship between two processes. Solid line indicates the packet stream line, which is used for transfer packet between two protocol layers. Press  to create a packet stream. The dashed line with one arrow means statistic wire. There is no traffic on the line, but during the simulation, two processes could transfer control data using op_stat function set. In our model, we use this technology between IGMP and MAC at host. Press  to create a statistic wire. The third kind of line  is dashed line with two arrows, which create a logic Tx/Rx Association.

Press  and drag the rectangle to one process, you can check its connectivity to other processes. OPNET lists all outgoing or incoming connections with their sources and destinations for you.

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