Book contents
- Frontmatter
- Contents
- List of illustrations
- List of tables
- Preface
- Acknowledgments
- Part I Introduction
- Part II Optical wide area networks
- Overview
- 5 Generalized multiprotocol label switching
- 6 Waveband switching
- 7 Photonic slot routing
- 8 Optical flow switching
- 9 Optical burst switching
- 10 Optical packet switching
- Part III Optical metropolitan area networks
- Part IV Optical access and local area networks
- Part V Testbeds
- Bibliography
- Index
7 - Photonic slot routing
from Part II - Optical wide area networks
Published online by Cambridge University Press: 10 May 2010
- Frontmatter
- Contents
- List of illustrations
- List of tables
- Preface
- Acknowledgments
- Part I Introduction
- Part II Optical wide area networks
- Overview
- 5 Generalized multiprotocol label switching
- 6 Waveband switching
- 7 Photonic slot routing
- 8 Optical flow switching
- 9 Optical burst switching
- 10 Optical packet switching
- Part III Optical metropolitan area networks
- Part IV Optical access and local area networks
- Part V Testbeds
- Bibliography
- Index
Summary
In our introductory discussion of all-optical networks (AONs) in Section 1.5.1 we have seen that the concept of lightpath plays a key role in wavelength-routing optical networks. A lightpath is an optical point-to-point path of light that interconnects a pair of source and destination nodes, where intermediate nodes along the lightpath route the signal all-optically without undergoing OEO conversion. As each lightpath requires one wavelength on every traversed link and the number of both wavelengths and links in AONs is limited for cost and efficiency reasons, it is impossible to interconnect every pair of nodes by a dedicated lightpath. Nodes that cannot be directly connected via a lightpath may use multiple different lightpaths to exchange data. In the resultant multihop optical network, each intermediate node terminating a lightpath performs OEO conversion. As a consequence, such opaque multihop optical networks are unable to provide transparency. Also, note that the transmission capacity between node pairs connected via a lightpath is equal to the bandwidth of an entire wavelength channel. This transmission capacity is dedicated and cannot be shared by other nodes, leading to wasted bandwidth under bursty nonregular traffic. To improve the bandwidth utilization of lightpaths, electronic traffic grooming becomes necessary at each source node.
To avoid the loss of transparency and the need for electronic traffic grooming of lightpath-based optical networks, a novel solution for the design of transparent mesh wavelength division multiplexing (WDM) wide area networks was proposed in Chlamtac et al. (1999b).
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- Chapter
- Information
- Optical Switching Networks , pp. 84 - 94Publisher: Cambridge University PressPrint publication year: 2008