The International Telecommunication Union created ITU-T Recommendation G.1050 / TIA-921 to describe a model for evaluating multimedia transmission performance over an IP network. It is a statistical model in which likelihood of occurrence values are assigned to all network elements and impairments. Test results using these statistical models are expressed in terms of network model coverage. Testing to a comprehensive statistical model suggests how communications devices may perform over an IP network in terms of network model coverage. This Recommendation focuses on the impact of impairments on layer 3 performance. IP streams from any type of network device can be evaluated using this model.

Emphasis is given to the fact that manufacturers of communications equipment and service providers are interested in a specification that accurately models the IP network characteristics that determine performance. Evaluators desire a definitive set of simple tests that properly measure the performance of communications devices from various manufacturers. Therefore, the objective of this Recommendation is to define a technology-independent model that is representative of the IP network, that can be simulated at reasonable complexity, and that facilitates practical evaluation times.  (Source:  ITU)

The Maxwell Network Emulator now supports all 1,512 test cases specified in the ITU-T G.1050/TIA-921.

Networked Multimedia Testing Model

Each one of Maxwell's tests for the G.1050/TIA-921 introduces a specific network anomaly or impairment that is likely to occur on today’s internet. The multimedia device under test, such as a voice over IP phone, or a video stream, must continue to operate correctly in the face of each network anomaly. The device must not crash or fail in any way.

These new multimedia devices containing voice or video streams are far more sensitive to network anomalies than traditional network devices, such as switches, servers or routers. When faced with routine network anomalies, the multimedia devices can suffer performance degradation or stop functioning.

The G.1050 provides a standardized model that all device manufacturers can utilize to test a range of known, deployed, network configurations containing network anomalies. In this way, the device manufacturer can test a multimedia product for each condition, and be certain that a product will perform reliably on today’s internet.

Additional New Media Tests

In addition to the G.1050/ TIA-921 network model tests, Maxwell also includes:

• SIP protocol impairment tests that check the robustness of SIP implementations to vulnerabilities and attacks

• A set of Rate Limitation Scenarios to determine how well the new multimedia device performs under bandwidth limited conditions

• Alternative network models that allow the user to go beyond the 189 rate combinations and eight severity levels of the ITU G.1050 and define a specific network anomaly to test a specific situation

The ITU-T G.1050 tests are available now from InterWorking Labs.  To learn more about using the ITU-T G.1050 / TIA-921 tests,  please contact InterWorking Labs.

The ITU-T G.1050 specification May be obtained from the ITU.