Throughput Test

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Frequently Asked Questions

Q. Why is the UDP downstream throughput value always zero?

A. This is a firewall issue. This means that the UDP data being sent from the server cannot reach the client. When performing UDP testing, the client sends upstream UDP traffic to the server from a random UDP port to the server port (27100 by default.) The return downstream traffic goes from port 27101 to the client source port. Use this information to configure your firewall.

Q. Why do I see very high (over 50%) UDP downstream loss?

A. This is normal if you're running the client on a WLAN station. UDP traffic is not acknowledged. This means that the party that sends traffic can send as much traffic as the networking system can handle without "caring" about how much of it will be lost. If you run the server on the wired side of the network, then a typical PC equipped with a gigabit adapter can send hundreds of megabits per second. These data will first reach a switch, which might be the first bottleneck, and then the access point, which is almost always a bottleneck, because a typical 802.11n access point cannot send more than 100 Mbps of data downstream, i.e. to the client. As a result, most of the UDP packets might be lost en route, but this is the only way to figure out the maximum downstream UDP throughput value.

Q. Why does the application require administrative privileges on Windows?

A. The lion's share of problems with throughput tests is related to firewalls. For this reason, we took the liberty of opening the Windows firewall for our EXE file. Our application creates a permissive firewall rule on launch and deletes it on exit. This requires administrative privileges.

Q. I entered a valid IPv6 address, clicked "Connect", and got the "No route to host" error. Why?

A. Link-local IPv6 addresses may require a zone index. For example, instead of fe80:0:0:0:6a5b:35ff:fed1:4633, which does not contain a zone index, you may need to use fe80:0:0:0:6a5b:35ff:fed1:4633%en0.

Q. Are the Windows, Mac, and Android versions interoperable?

A. Yes, you can run the server on a Mac and the client on a Windows machine or vice versa. The Android client can work with either a Mac or a Windows server.