Keywords: RFC1242; RFC2544; throughput; throughput rate.
Throughput overview:
Throughput is the throughput rate. The term was first proposed in RFC1242. It is the primary indicator for evaluating the performance of network equipment. Its definition is the maximum forwarding rate without the frame loss of the device . Usually, the maximum passed per second Measured by the number of data packets (PPS / FPS) or the number of bits (bit / s, Kbit / s, Mbit / s, Gbit / s ...), the test formula is: rate = total length / frame length , in simple terms, it is from The maximum amount of data that can be transmitted from the source sender to the destination receiver. For an Ethernet system, the absolute maximum throughput rate should be equal to the interface rate. In fact, since different frame lengths have different transmission efficiency, these absolute throughput rates cannot be achieved. The smaller the frame, the lower the transmission efficiency due to the preamble and frame interval.
In the above, we mentioned the formula for measuring the rate: rate = total length / frame length. Before looking at this formula, there are a few variables that everyone should be clear about:
①rate: FPS (frame per second);
②frame length includes preamble and start
Symbol and frame interval; ③Frame length = 64 + 7 + 1 +12 = 84Bytes = 84x8 = 672 bits;
④Rate = 1000x106 / 672 = 1,488,095; ⑤Frame
interval is 12bytes; the interval between two frames.
In terms of frame length selection, the RFC 2544 test standard recommends selecting the following seven types, namely 64, 128, 256, 512, 1024, 1280, and 1518 bytes. So why choose these seven values? Minimum 64Bytes: The reason is determined by the characteristics of Ethernet (CSMA / CD). 128, 256, 512, 1024, and 1280 are the most error-prone values for device processing, and the maximum is 1518Bytes: The reason is that the initial development of Ethernet was limited by the technology at that time. .
In addition, the throughput sometimes refers to the throughput of 64 bytes. The smaller the frame length, the more frames that need to be forwarded per second. The more frames that are forwarded, the more resources are consumed. The greater the resources consumed, the more likely the device will lose packets. . Usually there is no packet loss for 64 bytes, and no packet loss for other bytes.
| Frame length | Frames per Second |
|---|---|
| 64 | 1488095 |
| 128 | 844594 |
| 256 | 452896 |
| 512 | 234962 |
| 1024 | 119731 |
| 1280 | 96163 |
| 1518 | 81274 |
Throughput-dichotomy search and
find ideas: In the test, a certain number of frames are sent at a certain rate, and the frames forwarded by the DUT are counted. If the number of frames sent is equal to the number of received frames, the sending rate is increased and the test is re-tested. If the received frame is less than the transmitted frame, you need to reduce the transmission rate and retest.
RFC2544 uses dichotomy to automatically find throughput. Introduction:
Initial rate: The rate used in the first test
Minimum rate: When the test fails and the current rate is equal to the minimum rate, the rate is no longer reduced Test
maximum rate: When the test passes and the current rate is equal to At the maximum rate, the
rate accuracy is no longer increased : when two adjacent rates are less than the accuracy, the test stops
Here we make a dichotomy application example: the first time the tester sends a frame at 50% rate
if there is no packet loss, the second time it sends a frame at 75% rate
75 = 50 + (100-50) / 2
if there is a loss Packets, the third time the frame is sent at a rate of
62.5 62.5 = 50 + (75-50) / 2
If there is no packet loss, the fourth time the frame is sent at a rate of
68.75 68.75 = 62.5 + (75-62.5) / 2
| content | value |
|---|---|
| Initial rate | 50% |
| Minimum rate | 30% |
| Maximum rate | 100% |
| Rate accuracy | 1% |
Xintai Renix Software Test Demonstration of Throughput of Device Under Test
Generally speaking, throughput is a relatively common indicator. If two systems with different numbers of users and user usage patterns are basically the same, it can be judged that the processing capabilities of the two systems are basically the same. The following introduces you to the specific test method of Shinetech Renix software. Here we simulate a test, the test description is as follows: DUT is a Layer2 switch, the two ports of the tester are connected to the two ports of the switch (gigabit), and the purpose is to test the throughput of the DUT.
Throughput process
1. Add frame
2. Occupy port
3. Select wizard
4. Select throughput
5. Configure interface
6. Configure flow
7. Configure test parameters
8. Configure throughput parameters
9. Run test
10. View results
11. Export report
Preparation: Adding a frame
Open the software
reservation port and
enter the IP address
Preparation: Appointment port
Test configuration
Choose Wizard
Choose RFC2544 Wizard
Select throughput test
Test item
selection throughput test
Select port
Select Port Select the port
to participate in the test
Configure interface
Configure the interface by
default, no interface,
select add interface
Wizard configuration interface
The wizard configures the interface
to fill it step by step as needed
Select interface
Select
the interface
MAC / IP etc. that the interface just configured can be modified
Choose a traffic model
Traffic Type
· For Switch, select Ethernet
Traffic Mesh
· Three options
· Choose according to your needs
Bidirectional
· Selected to indicate two-way traffic
· There is an arrow on the traffic to indicate
Select test parameters
In the learning mode, for the Switch, choose two-layer learning, and the learning frequency is selected according to the needs. The result shows the delay, the type is selected according to the Switch forwarding type, and finally the result is saved.
Configure RFC2544 parameters
RFC2544 Key parameter description
Test time
· Default 60 seconds
· RFC2544 stipulates a minimum of 60 seconds
test times
· Default 1 time
· RFC2544 is not specified
· Can be configured multiple times, take the average
· Minimum rate: When the test fails and the current rate is equal to the minimum rate, the speed test is no longer reduced.
· Maximum rate: When the test passes and the current rate is equal to the maximum rate, the speed test is no longer increased.
· Initial rate: used for the first test rate
* rate accuracy: the accuracy rate is smaller than when the two adjacent, the test is stopped
· can percentage loss: when the packet loss rate is less than the threshold value, also referred to as the test by
· Take 7 special bytes to test by default
Configuration: Smart Script is automatically generated
Smart Script
generated automatically based on the configuration Smart Script
right pop up automatically
Configuration: Start testing
Click the Start button to start the test
testing report
Test progress view
· Message interface, real-time display of the current test bytes
· estimated progress
Result Analyzer pops up automatically
Results analysis
· Professional software
· Auto popup
Manual opening
· Automatic installation
· Opening result
Result Analyzer
Result analysis
· Click RFC2544 to summarize the results
· Throughput column indicates throughput (bidirectional)
Test report export
Export format (PDF / HTML)
result customization: By default, all test content will be saved, the test results are too detailed, and you can choose a summary template, and only save the summary information.
Test report content
Open test report
· Automatically pop up PDF
· View throughput (Thoughput column)
· Configuration information: Contains the current test configuration information
