OPTICAL NETWORKS

CONTENTS 1. History of Optical Networks 2. About Optical fiber. 3. Synchronous Optical Network 4. SONET Features 5. When Is a Separate SONET LAYER Needed? 6. SONET Network Elements 7. SONET Network Configurations 8. SONET Benefits 9. Conclusions 10.Bibliography

OPTICAL NETWORKS  Definition: Optical networks are high-capacity telecommunication networks based on optical technologies and components that provide routing, and restoration at the wavelength level as well as wavelength- based services Optical networks are high-capacity telecommunication networks based on optical technologies and components that provide routing, and restoration at the wavelength level as well as wavelength- based services

overview  As networks face increasing bandwidth demand, so network providers are moving towards optical network.  It provides higher capacity and reduced costs  for new applications like as the internet, video and multimedia interaction and advanced digital services.

History of Optical Networks  In the early 1980s, a revolution in telecommunications networks began & Since the tremendous cost savings and increased network quality has led to many advances in the technologies required for optical networks  Throughout this history, the digital network has evolved in three fundamental stages: asynchronous, synchronous, and optical

Asynchronous  pertaining to a transmission technique that does not require a common clock between the communicating devices.  The first digital networks were asynchronous networks.  Bit errors.  Difficult to interconnect

Synchronous  pertaining to a transmission technique that requires a common clock signal between the communicating devices in order to coordinate their transmissions  The need for optical standards  SONET standardized line rates, coding schemes, bit rate hierarchies, and operations & maintenance functionality.

About Optical Fiber  What is fiber optics?  What is optical networking?  The main components of a fiber optic system include Transmitter Transmitter Fiber optic cable Fiber optic cable Receiver Receiver  Fiber optic cable: what is it and what types are there?

Inside an optical fiber 1) Core 2) Cladding 3) Coating

Types of fiber 1.multi mode 2. single mode

SONET/SDH  Definition Synchronous optical network (SONET) is a standard for optical telecommunications transport. SONET standard is expected to provide the transport infrastructure for worldwide telecommunications for at least the next two or three decades.

SONET Features Network management Network management Bandwidth management Network simplification Network simplification

When Is a Separate SONET LAYER Needed?  Reliable transmission  Ultra fast protection mechanisms  Fastest transmission speeds  Long-distance transmission  multiplexing scalability (1.5 Mbps to 10 Gbps)  Global Reach

Some possible Topologies for a SONET point to point Network  Mesh Topology  Star Topology  Ring Topology

Mesh Topology  Advantages:  Few Traffic Problems  Robust to Failures  Privacy and Security  Disadvantages:  Cabling is Expensive Figure from:

Star Topology  Advantages:  Less Expensive (Cabling)  Robust to Link Failures  Disadvantages:  Less Secure  Central Point of Failure (Hub) Figure from:

Ring Topology  Advantages:  Simplicity  Disadvantages:  Lack of topological node degree Figure from:

SONET Benefits  improved services  Survivable network  reduced operating cost  centralized management  reduced capital investment

Conclusions Continued advancements in optical technology promise continued change as the optical network evolves to the ultimate goal of end-to-end wavelength services. Continued advancements in optical technology promise continued change as the optical network evolves to the ultimate goal of end-to-end wavelength services.  Consumers will have access to new high- bandwidth services made possible by the increased capacity afforded by the optical layer.

Reference Reference  SONET, Walter J. Goralski, McGraw-Hill Series on Computer CommunicationsKathy Benninger, Pittsburgh SuperComputing Center  Leo Donnelly, Harvard University  Mark Johnson, North Carolina Research & Education Network  Ron Hutchins, Georgia Institute of Technology/Southern Crossroads (SoX)  Sarah Morford, Grant County Public Utility District  John Nichols, Virginia Tech  Ana Preston, University of Tennessee  John Streck, North Carolina State University  Troy Travis, University of South Carolina  Bill Wing, Oak Ridge National Laboratory

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