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Spirent TestCenter: RFC 6349 Benchmarking Methodology Wizard for TCP Throughput Testing

Summary
RFC 6349 is implemented as a Spirent TestCenter wizard accessed from the Wizards menu, available in Spirent TestCenter version 5.21 and later. The wizard adopts a broadly similar workflow as the other Spirent TestCenter benchmarking methodology wizards such as RFC 2544 and RFC 8239.
Note: Refer to the application online Help for the wizard user documentation.

RFC 6349 is provided under a new license and is dependent on the Spirent TestCenter Enhanced Layer 4-7 license (BPK-2001) which must be purchased separately.
The wizard guides the user through the necessary steps to configure and run the test. Steps include port selection, endpoint configuration (IP addresses etc.), endpoint selection, and throughput parameter configuration.
RFC 6349 is a methodology used to measure end-to-end TCP throughput in a managed IP network. It provides accurate TCP throughput measurement and a practical test approach that specifies tunable parameters such as link speed, RTT (Round-Trip Time), MTU (Maximum Transmission Unit), and Socket Buffer sizes. It can be used to determine how these factors affect TCP performance over an IP network.

For an RFC 6349 test, with already saved configurations, users must select the following TestCenter IQ settings for the correct calculation of TCP retransmitted bytes and TCP efficiency.
Under TestCenter IQ Setting > Enhanced L4-7 > Server Results >TCP Server, users must enable Total Retransmitted Bytes (bytes). 


The wizard builds a sequence of test loops that utilize the Enhanced L4-7 Raw TCP protocol for traffic generation. The wizard configures an outer loop with multiple iterations: client-to-server traffic (Tx only), server-to-client traffic (Rx only) and bidirectional traffic (Tx+Rx). In each of these outer loop iterations, there is an inner loop which exercises different TCP receive window size configurations based on a percentage of the Minimum (Ideal) TCP receive window size (called Minimum RWIND). The calculation is explained in RFC 6349 section 3.3.1. The inner loop iterates over these different Minimum RWIND sizes, executes the tests, and gathers statistics to present in the result.

An example of the resulting test iterations is shown in the table.
Iteration Traffic Direction %Min RWIND Size
Iteration 1 Tx Only 25%
Iteration 2 Tx Only 50%
Iteration 3 Tx Only 75%
Iteration 4 Tx Only 100%
Iteration 5 Tx Only 125%
Iteration 6 Rx Only 25%
Iteration 7 Rx Only 50%
Iteration 8 Rx Only 75%
Iteration 9 Rx Only 100%
Iteration 10 Rx Only 125%
Iteration 11 Tx+Rx 25%
Iteration 12 Tx+Rx 50%
Iteration 13 Tx+Rx 75%
Iteration 14 Tx+Rx 100%
Iteration 15 Tx+Rx 125%

 

Product : Spirent TestCenter