This documentation is released under the Creative Commons licenseMessages sent by EtherMAC mark the beginning of a transmission. The end of a transmission is not explicitly represented by a message, but instead, the EtherMAC calculates it from the frame length and the transmission rate. Frames are represented by EtherFrame.
When frames collide, the transmission is aborted -- in this case EtherMAC makes use of the modelled jam signals to figure out when colliding transmissions end.
When a transmitting station senses a collision, it transmits a jam signal. Jam signals are represented by a EtherJam message. When EtherMAC received a jam signal, it knows that one transmission has ended in jamming -- thus when it receives as many jam messages as colliding frames, it can be sure all transmissions have been aborted.
Receiving a jam message marks the beginning (and not the end) of a jam signal, so actually EtherMAC has to wait for the duration of the jamming before assuming the channel is free again.
In burst mode, filled inter-frame gaps are represented with EtherFilledIFG packets.
Carrier extension is modelled by simply adding to the frame length, using the addBitLength() method of cPacket.
This documentation is released under the Creative Commons license