40.3.0.0.1 Exponential On/Off

An Exponential On/Off object is embodied in the OTcl class Application/Traffic/Exponential. The member variables that parameterize this object are: rX packetSize
_ & the constant size of the packets generated
burst
_time
_ & the average ``on'' time for the generator
idle
_time
_ & the average ``off'' time for the generator
rate
_ & the sending rate during ``on'' times
Hence a new Exponential On/Off traffic generator can be created and parameterized as follows:

        set e [new Application/Traffic/Exponential]
        $e set packetSize_ 210
        $e set burst_time_ 500ms
        $e set idle_time_ 500ms
        $e set rate_ 100k

NOTE: The Exponential On/Off generator can be configured to behave as a Poisson process by setting the variable burst_time_ to 0 and the variable rate_ to a very large value. The C++ code guarantees that even if the burst time is zero, at least one packet is sent. Additionally, the next interarrival time is the sum of the assumed packet transmission time (governed by the variable rate_) and the random variate corresponding to idle_time_. Therefore, to make the first term in the sum very small, make the burst rate very large so that the transmission time is negligible compared to the typical idle times.