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7.9.3. Packet Loss Test
Packet Loss
test measures the percentage of packets that are not forwarded (therefore, lost) due to the
lack of resource. This test helps to determine a DUT's ability to deliver frames in a sequenced flow of
streams with specific routing priorities and at a frame size step. Buffers on a DUT can greatly minimize
latency until they are full. It can provide a valuable baseline for latency tests by using this test to determine
the load at which the DUT drops packets.
Sources of packet loss include:
network congestion
packets arriving too late
out of sequence packets
frame errors
Test method:
The test runs according to the parameters specified for test duration, start frame size, a frame size step by
which to increase the load during the test, and a stop frame size at which the test ends. During the test,
these values determine the overall duration for which the DUT is tested.
DApps-QoS calculates frame loss as:
Frame Loss = Number of Frames Transmitted - Number of Frames Received
For each specified load percentage, the test progresses through these stages:
1. DApps-QoS first sends a frame burst at the specified start frame size for the specified period of time.
2. After all frames are sent in all flows, DApps-QoS queries the receiving ports to determine how many
frames were received.
3. DApps-QoS calculates total frame loss and out of sequence frames for each group, and each flow in
each group at that load percentage.
4. DApps-QoS then steps up the load and sends a frame burst for the specified period of time. It repeats
Steps 2 and 3 until it reaches the maximum load specified.
The loading and testing time can be customized to simulate real-world scenario; thus, giving the user a
clear view of DUT’s performance limits under different loading environments.
Test Iterations
Continuous
Click to activate continuous testing with the same settings.
