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How to understand the Bandwidth Quality Test for VOIP
The speed test that Phone Power uses tests the connection you would make as if a phone call was connecting through the Phone Power servers. This test will show a basic idea of what your current download and upload speeds are as well as the Maximum Pause, Jitter, and any packet loss that your internet connection is experiencing.
Please run any speed test at least 3 times in a row with no files being downloaded or uploaded, or any VIOP phone conversations. This will enable you to see a basic outline of the connection stability.
To run the test multiple times, please press the Refresh button on your internet browser window after the test completes and you have looked over the results.
Click here to test your speed with VIOP
QoS Percentage
- The QoS measure is a measure of consistency of the data flow, a low percentage indicates that the connection is behaving erratically. However, a connection can have good quality, consistent upload and download speed, and also have slow speed, low kilobytes per second transfer rate.
Max Pause
- The Max Pause reports the maximum amount of time spent waiting for data to arrive. A high Max Pause value is a sign of a bad connection. In a good test, this value will be less than 15ms to 30ms.
- A high pause will cause many issues with voice quality.
- It slows down your phone conversations.
- Untimeliness can result in overlapping noises, with one speaker interrupting the other.
- Can generate an echo.
- Drops in phone conversations.
- One way audio.
Round Trip Time (RTT)
- The Round Trip Time reports the time it takes for data to travel to the target destination for the speed test and back. The RTT provides a clue to the length of the journey between you and the testing server. The length of the journey will affect the performance of the test. Ideally the lower the RTT the better, less than 70ms. However, for certain tests such as trans-Pacific or trans-Atlantic, the results may be higher.
Jitter
- Jitter is the variation in time between data packets sent and packets arriving caused by network difficulties such as route changes, congestion, packet loss, traffic regulators etc., and plays a major role in the quality of a VoIP call. Excessive jitter occurs when the time delay is too long, high latency, and packets arrive outside the time window and get lost from the call. As a result, the recomposed sound no longer reflects exactly what was sent and depending of the extent of the delay may not be understandable by the recipient.
Packet loss
- This plays a key role in the quality of VoIP connections, as high packet loss causes some of the voice data not to arrive to the recipient. Packet loss occurs when voice packets are discarded by the jitter buffer or dropped by network routers/switches due to high congestion. This test measures the percentage of packet loss and reports the associated level of sound quality.
- Packet loss of any sort is unacceptable.
- If any packet loss is found on any speed test, please contact your internet service provider to assist with resolving the issue.
Mean Opinion Score (MOS)
- MOS gives a numerical indication of the perceived quality of the media received after being transmitted and eventually compressed using codecs.
- Taken in whole numbers, the numbers are quite easy to grade.
* 5 - Perfect. Like face-to-face conversation or radio reception.
* 4 - Fair. Imperfections can be perceived, but sound still clear. This is (supposedly) the range for cell phones.
* 3 - Annoying.
* 2 - Very annoying. Nearly impossible to communicate.
* 1 - Impossible to communicate
Here are a few tests to compare to:
- Delay is measured in milliseconds - 1000 milliseconds is equal to 1 second.
- This test is a 'Good' Test.
- This test shows the high Jitter.
- This test shows a 'Poor' test.
What makes this test a poor test is the high Maximum Pause, high round trip times and high jitter that the test saw while the test was running.
- To resolve issues with tests that look like this one, please contact your Internet Service Provider to improve the test results.
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Last Modified:Tuesday, June 23, 2009
Type: FAQ
Rated 5 stars based on 1 vote.
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