Voice: Network Voice Quality

Network Voice Quality, is a benchmark that measures VoIP lag under network stress; therefore, the Network Voice Quality tool is a good way to measure the quality of your network for VoIP. The Network Voice Quality test can be run from any Windows PC with an Internet connection.

To run the actual test, you need access to the Internet. The test is located at: http://streamengine.ubicom.com/html/lower.cfm? page=test_your_network.network_voice_quality

The following chart is a sample test report.

The Network Voice Quality test includes two parts:

1. The first part, the Internet Voice Quality, measures VoIP lag without any background data transfers to load the network. This tests the quality of your Internet connection itself.
2. The second part, Home Voice Quality, measures the ability of the network to prevent VoIP lag even when there is other traffic present on the network. The tool uses background data transfers to load the network during the Home Voice Quality stage of the test.

Explanation of scores:

Network Voice Quality: HIGHER IS BETTER. Overall score as calculated by the Network Voice Quality Test.

Latency: LOWER IS BETTER. Latency is the one-way delay that characterizes the network impairment that affects VoIP calls. It is the average amount of time necessary to transmit information from the application layer of one caller to another.

Jitter: LOWER IS BETTER. Jitter is the variance of latency.

Packet Loss: LOWER IS BETTER. Packet Loss is the percentage of bytes lost during the VoIP call.

Network Voice Quality Test

1. What do the results mean?  

Home Voice Quality:  Home Voice Quality shows how well your home network is set up to handle voice calls alongside other typical network applications.  This phase of the test simulates both a Voice over IP call, and sending files to the internet simultaneously.  Internet connections have limited bandwidth.  File transfers can compete with voice calls for the limited bandwidth available on the internet connection.  This can result in lower voice call quality on busy networks unless the home network has a Quality of Service engine that works properly.  This test result depends on the quality of your internet connection and on the features and configuration of the home network.    This phase of the test also uses Network Voice Quality to measure voice quality.

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2. What is Network Voice Quality?
 

Network Voice Quality, describes the perceived quality of a voice call.  The Network Voice Quality test tool generates test data streams that simulate a voice call being made between the user’s home computer and a test server on the internet.  The tool measures the amount of time it takes data to travel from the home computer to the test server and if any packets have been lost along the way.

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3. How is Network Voice Quality Calculated?
 

The voice quality test measures the condition of your network and uses a numerical model to predict the quality of voice calls made under these conditions.  This model uses measurements of delay, jitter, and packet loss on the network to predict call quality.  The International Telecommunications Union, or ITU, defined the E-Model in recommendation G.107.  This test uses a modified version of the E-Model to estimate Network Voice Quality Score on your home network.  The original E-Model was developed by compiling satisfaction ratings for real voice calls under carrying network conditions.

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4. How do I set up my router and PC for the test?  

Routers that feature StreamEngine technology are already designed to identify and prioritize voice calls without configuration.  StreamEngine will also treat background traffic, such as that used in the test, with a low priority.  This detection process is not port based.  However, most Home Voice Quality engines use a port-based prioritization scheme.  The test uses different ports for specific traffic types.  If your home router does not use StreamEngine, you should configure the following priority levels.

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