Voice over IP Telephone Network
Evaluating the response time and the audio quality acoss the Internet. Each device is modeled as a network node and processing capacity.Browsable image of the model.
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In this model each node is separated by a distance and is connected via
Routers and VoIP Gateways. The Operator is represented as a Traffic
Generator block
that generates a packet at a fixed rate called “Packet Rate”. Packet
Rate is configured to 5.0e-5, 20.0e-5 and 30.0e-5. The initial
connection establishment
delay is a parameter.
To simulate failures, the processing units are overloaded with the
application of external tasks. These tasks are high priority
independent tasks
(which are not connected to the regular flow).
The processing units- IP_Phone1, IP_Phone2 and the CPU are
overloaded by enabling the Enable_Load parameter. The new overloading
tasks steal
processing cycles that were previously available for VoIP.
-
The external task for IP_Phone1 is triggered every 90us and each task
takes 1000 processing cycles.
For a SystemResource running at 166MHz, a 1000 cycle produces a stall time of 6.02us.
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The external task for IP_Phone2 is triggered every 90us and each task
takes 1000 processing cycles.
For a SystemResource running at 166MHz, a 1000 cycle produces astall time of 6.02us.
- The external task for CPU in the External_Gateway is triggered
every
90us and each task takes
500 processing cycles. For a SystemResource running at 166MHz, a 500 cycle produces a stall time of 3.01us.
The following are the statistics comparison with and without overloading. The overloading increases the resource utilization and the processing latency significantly.
