
116 The Practical OPNET User Guide for Computer Network Simulation
5.2.1 ExPlIcIt traFFIc MOdEls
Explicit trafc models provide a very accurate description of trafc behavior, which
is achieved by modeling the complete life cycle of every packet generated by the traf-
c sources. Packet trafc is the lifeblood of an OPNET simulation as the data packets
owing through the protocol layers invoke the various functions in those protocols.
Typically, the data generated by the trafc sources is split into messages or packets and
is then sent to the lower protocol layers that further segment, encapsulate, fragment,
queue, forward, receive, reassemble, ...