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Network QoS design and reliability management

[Principal research results]

Research result 1

Application quality monitoring technology

①Web-browsing applications

Because web browsers are installed in various devices, application services that are provided through web browsers (web-browsing applications) are in widely use. With traditional web-browsing applications, the entire displayed page is simply changed as the user navigates the application. However, these days, in line with the development of browsing technologies, web-browsing applications that can dynamically display content such as Ajax or Flash are common.
The QoS of traditional web-browsing applications can be guaranteed by setting limits for the time to redisplay whole pages, etc., providing servers and network resources that satisfy the objectives, and monitoring them. However, for recent web-browsing applications, there is no known indicator that can quantify QoE, and the resource requirements which can satisfy QoE are also unknown.
In view of these circumstances, we are working on the following issues regarding web-browsing applications that use dynamic content.
[quantifying quality] define quality indicators that quantify web-browsing application QoE
[monitoring quality] map the monitorable information to KQI/KPI/QoE
[isolating the cause of quality deterioration] if quality deteriorates, isolate the cause: the server and network or the user terminal

Fig. 2: Illustration of quality monitoring technology on web-browsing application

Fig. 2: Overview of network QoS design technology

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②Progressive download video service

Video distribution services have become popular recently, not only for PCs that access the Internet via a fixed connection, but also smart phones and tablets with WiFi or 3G Internet access. With these video distribution services, user demands for good video quality is relatively high, and the load required for maintenance is expected to increase, as the use of these services spreads.
Therefore, a technique that enables the quantitative quality to be determined remotely if users report quality deterioration, is important in order to develop initial systems that are appropriate for maintenance bases and to reduce operation costs.
We are now working on methods to estimate video quality from packet capture data (specifically, the stop time of video play), which are intended for video distribution services, especially progressive download* services.
Thus, efficient maintenance will be possible combining our technique and a technique to isolate the suspected point, if users report quality deterioration.

*progressive download: distribution system that plays video while downloading content data from HTTP servers

Fig. 3: Use case of quality estimation technology on progressive download service

Fig. 3: Overview of network QoS control technology

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Research result 2

Network QoS measurement and analysis technology

In order to evaluate the network QoS characteristics of telecommunications networks under operation, it is important to define network QoS parameters, to determine measurement methods for these parameters, and to establish analysis methods for measurement results. With these technology, it make possible to accurate and efficient network QoS monitoring in the telecommunications networks' operation.

For example, we are continuously working on sampling measurement and analysis of QoS value of IP telephony networks. Through these analysis, we have validated the basic technology for measurement and analysis of network QoS, and we have studied with the aim of developing network QoS standards. In addition, we are contributing to the refinement and development of QoS measurement and analysis technologies through performance evaluation for commercial measurement equipments, proposal to standardization organizations, and so on.

Fig. 1: Illustration of network QoS measurement in IP telephony network

Fig. 1: Illustration of network QoS measurement in IP telephony network

Click on image for larger version.