EtherBus

simple module

Implements the shared coaxial cable for classic Ethernet.

The ethg[i] gates represent taps. Messages arriving on a tap travel on the bus on both directions, and copies of it are sent out on every other tap after delays proportional to their distances.

For the model to work correctly, all connecting links (both incoming and outgoing ones) must have the same datarate.

Messages are not interpreted by the bus model in any way, thus the bus model is not specific to Ethernet.

It is allowed to disconnect/reconnect links at runtime. However, the model does not support changing the tap positions or adding/removing taps at runtime.

Parameters

Name	Type	Default value	Description
positions	string		positions of taps on the cable in meters, as a sequence of numbers separated by spaces. If there are too few values, the distance between the last two positions is repeated, or 5 meters is used.
propagationSpeed	double	200000000mps	signal propagation speed on the bus

Properties

Name	Value	Description
networkNode
labels	node
display	b=200,5,,,,1

Gates

Name	Direction	Size	Description
ethg [ ]	inout		to stations; each one represents a tap

Source code

//
// Implements the shared coaxial cable for classic Ethernet.
//
// The ethg[i] gates represent taps. Messages arriving on a tap
// travel on the bus on both directions, and copies of it are sent out
// on every other tap after delays proportional to their distances.
//
// For the model to work correctly, all connecting links (both incoming
// and outgoing ones) must have the same datarate.
//
// Messages are not interpreted by the bus model in any way, thus the bus
// model is not specific to Ethernet.
//
// It is allowed to disconnect/reconnect links at runtime. However,
// the model does not support changing the tap positions or adding/removing
// taps at runtime.
//
simple EtherBus
{
    parameters:
        @networkNode();
        @labels(node,ethernet-node);
        @display("b=200,5,,,,1");
        string positions;  // positions of taps on the cable in meters, as a sequence
                           // of numbers separated by spaces. If there are too
                           // few values, the distance between the last two positions
                           // is repeated, or 5 meters is used.
        double propagationSpeed @unit("mps") = default(200000000mps); // signal propagation speed on the bus
    gates:
        inout ethg[] @labels(EtherFrame-conn);  // to stations; each one represents a tap
}

File: src/inet/linklayer/ethernet/EtherBus.ned