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Quality degradation analysis for large-scale networks
from CONSENSUS:"Ongoing Innovation"[Japanese Only]
Technology to quickly recover from major network faults that can adversely affect society
Networks are now an established part of society and increasingly important to economic activity. In the future, society is expected to rely even more on networks, such as, as an emergency lifeline in time of disaster. Thus any kind of network fault can have a huge impact on society. On the other hand, networks are becoming larger and the network equipments are becoming more diverse with multi-vendor configurations. In addition to structural complexity, networks are being used with an increasing diversity of applications such as VoIP and video delivery systems. Under this type of large-scale and complex network environment, it becomes more difficult to pinpoint the cause of trouble (quality degradation) when problems occur.
NEC Laboratories started to develop technologies related to "quality degradation locating for large-scale networks" over two years ago in response to society needs and the rapid introduction of VoIP equipment within enterprises. These technologies are expected to be able to quickly locate the point at which the quality of an application degrades on a large-scale network. They are thus valuable tools for recovery from network faults.
Existing network management systems are only able to detect "obvious" faults such as router stoppages or line disconnections. However, with the spread of VoIP and video delivery systems, it becomes imperative to detect, locate, and remedy the silent faults (e.g. voice skipping, video disruption) that have begun to surface. Until now, such faults have been beyond the scope of network management systems.
Like a CT scan, analyzing problems with a minimum of information from external observation
One approach to the detection of faults is to monitor the entire network. However, the cost of collecting such a massive volume of data and of monitoring each link on the network has proven to be prohibitive. A new promising approach under development is "network tomography," which analyzes internal problem areas using a minimum of information from external observation. The concept of network tomography is related to medical computed tomography in which a 3D image of the internals of an object is generated from a large series of 2D X-ray images. Similarly, network tomography is a technology used to collect information on the transmission quality of various routes and then to analyze the internal network state from this information.
To achieve an accurate locating on large-scale networks, NEC Laboratories has developed two technologies: 1) Application flow analysis and 2) Network partitioning extension. Application flow analysis is a method to locate the quality degradation from end-to-end quality and routing information. This technology does not rely on the direct measurements on physical transmission lines (links). Collecting information at each end of the network eliminates the cost of deploying measurement equipment inside the network and reduces the volume of analysis data by up to 90%. Network partitioning extension can be used on large-scale networks to improve the speed of analysis even further. With this technology, the calculation speed can be reduced by one-half to one-twentieth. In environments with multiple providers where it is very difficult to specify the source of a fault, the new technologies enable both analysis of each network provider and quality management of the entire network.
After successful in-house implementation, NEC Laboratories is now trying to start conducting proof-of-concept experiments on the technology among carriers and Internet service providers (ISPs). In the future, these technologies will be marketed as a network administration product for large corporate networks as well as carriers and ISPs.
Network operation management costs are now said to account for up to half the cost of an information system. So it is obvious that administrators are reaching the limit of their ability to monitor networks. Platform technology for "quality degradation locating for large-scale networks" will assist both network administration and the entire field of information and communications technology.
NEC Labs expects this research to develop widely as an innovation used to support the diverse information and networking needs of people and society.
This project has partly been supported by the Ministry of Internal Affairs and Communications (MIC).
