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
4 - p-cycle protection
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
The p-cycle (preconfigured protection cycles) is a cycle-based protection method introduced in. It can be characterized as embedding of multiple rings to act as protection cycles in a mesh network. The p-cycles are configured with spare network capacity to provide protection to connections. The design goal of p-cycle protection is to retain the capacity efficiency of a mesh-restorable network, while approaching the speed of a line-switched self-healing ring. In p-cycle protection, when a link fails, only the end nodes of the failed link need to perform real-time switching. This makes p-cycle similar to SONET/SDH line-switched rings in terms of the speed of recovery from link failures. The key difference between p-cycle and ring protection is that p-cycle protection not only protects the links on the cycle, as is the case for ring protection, it also protects straddling links. A straddling link is an off-cycle link for which the two end nodes are both on the cycle. This important property effectively improves the capacity efficiency of p-cycles. Figure 4.1 depicts an example that illustrates p-cycle protection. In Fig. 4.1(a), A–B–C–D–E–A is a p-cycle formed using reserved capacity on the links for protection. When an on-cycle link A–B fails, the p-cycle can provide protection as shown in Fig. 4.1(b). When a straddling link B–D fails, each p-cycle protects two working paths on the link by providing two alternate paths as shown in Figs. 4.1(c) and (d), for the entire traffic on the link in both directions.
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- Publisher: Cambridge University PressPrint publication year: 2006