NetDoppler

Please note that NetDoppler is a free utility. Maintenance and support are not offered with this product.

Current Version

1.1.1.69

FAQs

• Where's the print command in NetDoppler?
• Why do I get asterisks for my packet stream throughput tests?
• What's the difference between packet stream and single packet throughput tests?
• NetDoppler installed fine but when I try to run the program why do I receive this error "faulting module netdoppler.exe, version 1.1.1.69, fault address 0x00002f80"?

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Where's the print command in NetDoppler?

NetDoppler does not have a built-in printing capability. Instead, throughout the application there is a built-in copy-to-clipboard functionality. Each graph has a small clipboard icon in the upper-right-hand corner that, when clicked, will copy the graph to the clipboard. On each chart or spreadsheet, you can right-click and choose copy. This allows you to export the graphs or charts data to other applications such as Excel or Word for printing as well as for inclusion in reports and the like.

Why do I get asterisks for my packet stream throughput tests?

The throughput test results depend on the devices between the machine running the test and the destination machine. From some locations you may receive only asterisks in the packet stream value field.

Asterisks in the packet stream fields means that one or more of the packets did not reach the destination, or that at least one device between the testing machine and the destination does not allow fragmentation of IP packets. If NetDoppler is on an Ethernet network, the network card will have to start fragmenting packets when the 'Amount of Data' field is increased above 1500 bytes. Some network devices, such as firewalls, disallow fragmentation for security reasons.

To determine if dropped packets or fragmentation is the issue, steadily reduce the value in the 'Amount of Data' field to see if at some point you start receiving a result. If, after reducing the amount of data sent, you consistently get a result, then most likely some device between your machine and the destination is disallowing IP fragmentation.

To determine which device is imposing the restriction, you would repeat this test starting from your test machine and working outward (following the traceroute) until your test is unsuccessful. This will be the device that is not allowing fragmentation of IP packets, or is dropping one or more of the stream packets.

What's the difference between packet stream and single packet throughput tests?

NetDoppler calculates throughput by measuring the round trip time it takes for data to be sent and received over the ICMP protocol (throughput = data / time). Two kinds of tests are performed--streaming and single packet throughput.

Streaming tests send the entire chunk of data in a single ICMP packet, which will be fragmented if it is greater than the Maximum Transmission Unit (MTU). Therefore, all of the data goes to the destination before the destination returns a reply.

Single packet tests send data over one MTU chunk at a time. In this test, a single MTU chunk is sent to the destination, to which the destination replies, and then another MTU chunk is sent and so on.

So, streaming tests measure achievable throughput for bursting protocols such as TCP, while single packet tests measure achievable throughput for ping pong protocols such as NCP. Streaming tests are directly affected by the amount of data that is used for testing; the more data you send, the better your throughput will be. In other words, round trip latency has less of a negative impact the more data you send over at once, since it is only incurred once. Compare this to single packet tests where the round trip latency is incurred for every single command/reply pair. Therefore, single packet tests are bound by latency, and the amount of data doesn't affect results.

NetDoppler installed fine but when I try to run the program why do I receive this error "faulting module netdoppler.exe, version 1.1.1.69, fault address 0x00002f80"?

We have seen this issue when running NetDoppler on newer high-performance machines, try installing the program on an older machine with less processing power.

If you continue to have problems, here are additional troubleshooting tips:

• Disable Hyperthreading. (Enter the BIOS to disable this feature.)
• Check your system's Event Viewer for errors that would indicate the problem. (Check Application & System Event Viewer logs.)
• Be sure there are no programs interfering, i.e., virus software, firewalls, network/card utilities.

Additional Support and Resources

If you still need assistance, please select one of the following links for additional support.

Downloads

MyPeek

Networking Resources

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