Book contents
- Frontmatter
- Contents
- Preface
- Acknowledgments
- 1 Optical networking technology
- 2 Design issues
- 3 Restoration approaches
- 4 p-cycle protection
- 5 Network operation
- 6 Managing large networks
- 7 Subgraph-based protection strategy
- 8 Managing multiple link failures
- 9 Traffic grooming in WDM networks
- 10 Gains of traffic grooming
- 11 Capacity fairness in grooming
- 12 Survivable traffic grooming
- 13 Static survivable grooming network design
- 14 Trunk-switched networks
- 15 Blocking in TSN
- 16 Validation of the TSN model
- 17 Performance of dynamic routing in WDM grooming networks
- 18 IP over WDM traffic grooming
- 19 Light trail architecture for grooming
- Appendix 1 Optical network components
- Appendix 2 Network design
- Appendix 3 Graph model for network
- Appendix 4 Graph algorithms
- Appendix 5 Routing algorithm
- Appendix 6 Network topology design
- References
- Index
15 - Blocking in TSN
Published online by Cambridge University Press: 18 December 2009
- Frontmatter
- Contents
- Preface
- Acknowledgments
- 1 Optical networking technology
- 2 Design issues
- 3 Restoration approaches
- 4 p-cycle protection
- 5 Network operation
- 6 Managing large networks
- 7 Subgraph-based protection strategy
- 8 Managing multiple link failures
- 9 Traffic grooming in WDM networks
- 10 Gains of traffic grooming
- 11 Capacity fairness in grooming
- 12 Survivable traffic grooming
- 13 Static survivable grooming network design
- 14 Trunk-switched networks
- 15 Blocking in TSN
- 16 Validation of the TSN model
- 17 Performance of dynamic routing in WDM grooming networks
- 18 IP over WDM traffic grooming
- 19 Light trail architecture for grooming
- Appendix 1 Optical network components
- Appendix 2 Network design
- Appendix 3 Graph model for network
- Appendix 4 Graph algorithms
- Appendix 5 Routing algorithm
- Appendix 6 Network topology design
- References
- Index
Summary
One of the important performance metrics by which a wide area network is evaluated is based on the success ratio of the number of requests that are accepted in the network. This metric is usually posed in its alternate form as the blocking probability, which refers to the rejection ratio of the requests in the network. The smaller the rejection ratio is, the better the network performance. Although other performance metrics exist, such as the effective traffic carried in the network, the fairness of request rejections with respect to requests requiring different capacity requirements or different path lengths, the most meaningful way to measure the performance of a wide-area network is through the blocking performance. To some extent the other performance metrics described above can be obtained as functions of the blocking performance.
Analytical models that evaluate the blocking performance of wide-area circuit-switched networks are employed during the design phase of a network. In the design phase these models are typically employed as an elimination test, rather than as an acceptance test. In other words, the analytical models are employed as back of the envelope calculations to evaluate a network design, rejecting those designs that are below a certain threshold.
Blocking model
The following assumptions are made to develop an analytical model for evaluating the blocking performance of a TSN.
The network has N nodes.
The call arrival at every node follows a Poisson process with rate λn. The choice of Poisson traffic is to keep the analysis tractable.
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- Survivability and Traffic Grooming in WDM Optical Networks , pp. 261 - 279Publisher: Cambridge University PressPrint publication year: 2006