OPTICAL NETWORKS. CONTENTS 1. History of Optical Networks 2. About Optical fiber. 3. Synchronous...

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Transcript of OPTICAL NETWORKS. CONTENTS 1. History of Optical Networks 2. About Optical fiber. 3. Synchronous...


  • CONTENTS 1. History of Optical Networks2. About Optical fiber.3. Synchronous Optical Network4. SONET Features5. When Is a Separate SONET LAYER Needed?6. SONET Network Elements7. SONET Network Configurations8. SONET Benefits9. Conclusions10.Bibliography

  • OPTICAL NETWORKSDefinition: 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

  • overviewAs 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

  • Asynchronouspertaining 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

  • Synchronouspertaining to a transmission technique that requires a common clock signal between the communicating devices in order to coordinate their transmissionsThe need for optical standardsSONET standardized line rates, coding schemes, bit rate hierarchies, and operations & maintenance functionality.

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

  • Inside an optical fiber1) Core 2) Cladding 3) Coating

  • Types of fiber1.multi mode 2. single mode

  • SONET/SDHDefinition

    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

    Bandwidth management

    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 Topologiesfor a SONET point to point NetworkMesh TopologyStar TopologyRing Topology

  • Mesh TopologyAdvantages:Few Traffic ProblemsRobust to FailuresPrivacy and Security

    Disadvantages:Cabling is Expensive

    Figure from: http://www.webopedia.com/TERM/t/topology.html

  • Star TopologyAdvantages:Less Expensive (Cabling)Robust to Link Failures

    Disadvantages:Less SecureCentral Point of Failure (Hub)

    Figure from: http://www.webopedia.com/TERM/t/topology.html

  • Ring TopologyAdvantages:SimplicityDisadvantages:Lack of topological node degree

    Figure from: http://www.webopedia.com/TERM/t/topology.html

  • SONET Benefits

    improved servicesSurvivable network reduced operating cost centralized management reduced capital investment

  • ConclusionsContinued 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

    SONET, Walter J. Goralski, McGraw-Hill Series on Computer CommunicationsKathy Benninger, Pittsburgh SuperComputing CenterLeo Donnelly, Harvard UniversityMark Johnson, North Carolina Research & Education NetworkRon Hutchins, Georgia Institute of Technology/Southern Crossroads (SoX)Sarah Morford, Grant County Public Utility DistrictJohn Nichols, Virginia TechAna Preston, University of TennesseeJohn Streck, North Carolina State UniversityTroy Travis, University of South CarolinaBill Wing, Oak Ridge National Laboratory