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Simulated NetworkThe figure below shows the configuration of the simulated ATM network. The application App_1 has one CBR traffic source, while the application App_2 has one VBR batch traffic source. The application App_3 also has one CBR traffic source, however no data is transmitted from this application that is used as traffic receiver in the simulation framework. Two ATM connections are established, one from BTE_1 to BTE_3, and the other from BTE_2 up to BTE_3. The CBR transmission is done with a data connection from App_1 to App_3, and VBR transmission with a data connection from App_2 to the same App_3. The CBR connection traffic has priority over the VBR connection traffic. These two data connections are established over the previously established ATM connections. The BTEs are connected through an ATM switch named SW_1.
The application App_1 transmits at a fixed rate of 18.56 Mbps packets with the size of 232 bytes. The application App_2 transmits packets with the mean size of 0.4 ATM cells and with a mean interval between packet batches of 2.7263 m sec. All the buffers of BTE and switch queueing systems are infinite buffers. The insertion of ATM OAM cells in the physical layer is disabled. The AAL5 packetization delay is 1nseg. The distance between the network elements is 10 meters. The signal propagation velocity in the optical fiber is considered as 300000 Km/sec, which results in a propagation delay of 33.33 nsec. The data transmission rate for all network links is 155.52 Mbps (OC-3) and the switch cycle time is 2.7263 m sec. Simulation Results In order to demonstrate the simulator results two simulations were performed: one for transient behavior and the other to observe the network steady state. In the transient behavior simulation were performed 1 ms of simulation time and in the steady state the simulator runs 5.5 s of simulation time. The following sections show the simulation results. Transient Behavior Figure 8 shows the traffic pattern generated by the applications App_1 and App_2. Figure 9 shows the BTE_1 and BTE_2 queueing system occupancy. Figure 10 shows the SW_1 output buffer occupation for the ATM and physical layers. Figure 11 shows BTE_1 and BTE_2 queueing system waiting time. Figure 12 shows the SW_1 output buffer waiting time for the ATM and physical layers.
Figure 8: Traffic pattern of applications App_1 and App_2
Figure 9: Occupation of BTE_1 and BTE_2 queueing systems buffers.
Figure 10: Occupation of SW_1 port 2 queueing system output buffers (ATM and physical layers).
Figure 11: Waiting time in BTE_1 and BTE_2 queueing system buffers.
Figure 12: Waiting time in SW_1 port 2 queueing system output buffers (ATM and physical layers). Permanent Behavior Figure 13 shows the mean number of cells in the network buffers. Figure 14 shows the waiting time in the network buffers. Figure 15 shows the utilization of network queueing system. Figure 16 depicts simulator performance in steady state.
Figure 13: Network buffers mean number of cells.
Figure 14: Network buffers mean cell waiting time.
Figure 15: Network queueing systems utilization.
Figure 16: Simulator performance in steady state. The steady state results showed in the figures can be verified using the queueing system theory. Transient Behavior Configuration File
Permanent Behavior Configuration File
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