Availability is one of the most critical aspects of a network design. Despite that, few organizations have a good understanding of how much availability they really need. Factors such as budget constraints, limited time, or skills and experience of the staff at hand are what decide the network design and availability obtained. As a result, most organizations end up with solutions that have a sub-optimal level of availability. These solutions will have either too much availability or worse, too little. In the former case, the extra cost of the solution could be saved and used for other Information Technology (IT) projects. In the latter case, the lack of adequate network availability could impact operation, which ultimately can harm the financial performance of the organization. In both cases, organizations can lose money; hence the importance of selecting the adequate level of availability.

This paper discusses different issues related to network availability. First, the paper presents some of the elements that impact the availability of a solution. Then the paper discusses how network designers can calculate the exact availability of their solution. Finally the paper provides means to determine the optimal level of availability. Using these elements, network designers should then be able to evaluate which of the options at hand provide that adequate level of availability.

© 2008 Optical Society of America

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