Throughput Test

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Understanding Your Results

During each testing cycle, the application performs five tests: sending and receiving TCP data, sending and receiving UDP data, and sending and receiving a time probe packet. Based on these tests, it computes TCP and UDP upstream and downstream throughput values (current, for the latest test, and averaged, for all tests), as well as the round-trip time. When all tasks in a cycle are completed, a new cycle automatically begins.


Throughput (also often referred to as "goodput") is the amount of application-layer data delivered from the client to the server (upstream) or from the server to the client (downstream) per second. The protocol overhead is not included, so when we talk, for example, about the TCP throughput rate of 1 Mbps, we mean that 125 Kbytes of actual data payload were sent between two network nodes during one second, not including TCP, IP, and Ethernet or 802.11 headers.

Packet Loss

Packet loss is applicable to UDP tests only, because in TCP, all packets must be acknowledged and no data loss may occur. UDP loss is calculated as the percentage of data that was lost during transmission. For example, let's interpret the following result:

UDP Down: 60.00 Mbps (Ave: 55.00), Loss: 40.0%

This means that during the latest test cycle, the server sent 1 megabit of data in 10 milliseconds (actual data amount and duration may vary; we use this number only as an example,) and the client received 0.6 megabits in 10 milliseconds, while 0.4 megabits were lost en route.

Round-Trip Time

Round-trip time (RTT) is the length of time it takes for a data packet to be sent from the client to the server and back. The application uses TCP packets for RTT measurements.