Communication Mediums for Signal, ITS, and Freeway Surveillance Systems Final Report (1996) / Chapter Skim
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A.4.1 General Overview: Maintainability of Advanced Communication Systems
A.4.1 General Overview: Maintainability of Advanced Communication Systems
Pages 437-449
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From page 437... ...
A.4.1 General Overview: Maintainability of Advanced Communication Systems A major concern of jurisdictions relating to the deployment of advanced communications technology is ability to maintain new technology. This issue involves several sub-issues including: · Ease of maintenance, a basic issue since it impacts training; · New gaining of the maintenance staff; · New test equipment requirements and availability; and · Spares requirements and associated cost of availability.
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From page 438... ...
to isolate failures in specific replaceable modules to a high degree of confidence; Safe, hot, change-out of failed modules eliminating the need to deactivate power and reinitialize the system; Test bus to support use of test equipment; and Use of fault propagation prevention to contain a fault, preventing Be distribution of "garbaged" data throughout Be communications network. Modem communications equipment is evolving to incorporate Be of the Test Architecture and Bus of Be loins Test Action Group and EKE's Pll49.5.
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From page 439... ...
A.4.~.1 Network Management Network management includes He hardware 'hooks" and associated software to facilitate management of a communications network Perhaps one of He most important aspects of modem commum cations system design is attention to including network management within the architecture. Network management generally involves: · Infrastructure Management: .
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From page 440... ...
seems to be He current "default" standard in the communications network industry. Openv~ew (Hewlett Packard, ~c.)
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From page 441... ...
The information network management win provide, when properly implemented, is '~hat has failed," "where it has failed," and "impact on system performance." This can be extended Trough applications software to include inventory control of spares, replaceable modules, plus scheduling and mon~tonng of repair activity. A4.~.2 Factory Backup For large communications network subsystems such as SONET node equipment, ATM switches, bndge-routers, and over tokens equipment is available with a remote diagnostics port.
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From page 442... ...
To be responsive, He Maintenance Organization must be within a suitable maintenance response distance from Me communications network. This typically means Mat Be Maintenance Organization is within Me jurisdictional area The type of contract service is a function of: · Use of fault tolerant equipment in Me field; · Any maintenance responsibility desired to be maintained by He jurisdiction such as: · Traffic controller maintenance, and Modem maintenance within traffic controllers; · Degree of intelligence in the field and ability of He distributed intelligence to safely support traffic control in case of a communications failure; · General jurisdicdonal traffic conditions; and · Responsibility for maintenance service to He electronics and cable infrastructure.
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From page 443... ...
With automated built-~n test capability and network management, contract maintenance may not be justified based on network complexity. With automated fault detection, isolation, and repordug through a properly designed communications network, the jurisdictional maintenance ~:`NCHR~\ N~3-51 · IF A4-7
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From page 444... ...
In summary, contract maintenance is available to jurisdictions, wig a savings in personnel, test equipment, and spares cost. By electing contract maintenance, a jurisdiction becomes vulnerable to increased maintenance service cost with few alternatives because He maintenance organizadon owns spares, test equipment, and maintenance knowledge.
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From page 445... ...
Advance communications equipment typically uses highly integrated circuitry which supports reduced component count Similarly, advanced communications equipment typically uses low power semiconductor components with low heat dissipation, unlike older technology. Lower power and heat dissipation supports higher reliability since semiconductor failure rate increases with junction temperature.
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From page 446... ...
This, combined w~ff1 the ability to Impose built-in testing down to the component level, the need for maintenance operations for advanced communications devices is decreased, and the ease of conducting a maintenance operation when needed is increased. A.4.~.6 Built-in Test Equipment As opposed to built-in tests, which are test features incorporated into the design of operational communications electronic equipments, test equipment may be integrated into the system.
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From page 447... ...
Test equipment supporting advanced communications technology is being designed to be: Compatible wad recognized test bus standards; Able to be integrated into a common system test capability; Able to be controlled and test results read by system bu~It-in test software supporting central network management capability; and Generally modularly expandable and tailorable Trough software (example is protocol analyzer)
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From page 448... ...
This means that Be system is supplied ninth modern BIT features and integrated test equipment to support maintenance operations and that cen~ized communications network management and monitoring are included In the system. Without attention to automated maintenance assistance in new systems, jurisdictional maintenance support for advanced technology implementation we most likely be limited.
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From page 449... ...
Thus, the functions of the advanced wireless digital transceiver and associated BIT are more easily understood as an extension of current knowledge. In summary, wad a basic knowledge of communications technology, advanced commun~cabons applying communications principles, built-in test features, and central network monitoring, a jurisdictional maintenance technician is capable of transition~ng from conventional to advanced communications network maintenance.
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