PDF of this tutorialThe test system architecture uses three layers to support the testing of the newly converged network. This tiered approach addresses the evolution of the network, revisions to business and maintenance processes, and changes in user skill.
The access layer of the architecture is colocated with network elements for physical measurement (switch) and data-stream monitoring (RAS). The locations shown in Figure 5 (in Topic 7) are representative, as these subsystems must be portable to alternative nodes such as DLCs or routers. They must also operate independently of each other to allow for separate ownership by ISPs or carriers.
The access layer is controlled by and reports its acquired information to a remote analysis layer. The expert systems residing there perform fault isolation using the access layer information as well as other inputs such as stored network characteristics (footprints), problem symptoms (customer trouble reports), line records, and customer records.
Analysis-layer actions are dynamically sequenced in response to guided interactions between the subscriber and the call center. Responses to queries generate further actions via additional questions directed to the consumer, access to documents on the Web, or requests of the fault-isolation system to perform its function. This is referred to as "guided fault isolation." These responses, also known as "guided repair," can instruct consumers on how to resolve cockpit errors or configuration problems.
A unique architectural need presents itself when expert system technology is used. Information must be collected to serve a variety of network, process, and user situations. Using a blackboard architecture (BBA) allows multiple "experts" to work in concert and manage knowledge (see Figure 7). These "experts" are specific reasoning paradigms (e.g., RBR) and contain information on one or more topics. They work together under the BBA, posting and retrieving intermediate results. Final results are decided by unanimous selection or, as is more likely the case, through further expertise contained in an arbitrator.
Figure 7. Blackboard Architecture
