Sonet Sdh Dwdm


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Sonet Sdh Dwdm

  1. 1. SONET
  2. 2. INTRODUCTION <ul><li>Digital transmission standards for fiber-optic cable </li></ul><ul><li>Independently developed in USA & Europe </li></ul><ul><ul><li>SONET (Synchronous Optical Network) by ANSI </li></ul></ul><ul><ul><li>SDH (Synchronous Digital Hierarchy) by ITU-T </li></ul></ul><ul><li>Synchronous network using synchronous TDM multiplexing </li></ul><ul><li>All clocks in the system are locked to a master clock </li></ul><ul><li>It contains the standards for fiber-optic equipments </li></ul><ul><li>SONET was originally designed for the public telephone network. </li></ul>
  3. 3. <ul><li>A bit-way implementation providing end-to-end transport of bit streams. </li></ul><ul><li>Multiplexing done by byte interleaving. </li></ul><ul><li>SONET commonly transmits data at speeds between 155 megabits per second (Mbps) and 2.5 gigabits per second (Gbps). </li></ul><ul><li>One of SONET’s most interesting characteristics is its support for a ring topology . </li></ul><ul><li>Very flexible to carry other transmission systems (DS-0, DS-1, etc) </li></ul>
  4. 4. SONET LAYERS <ul><li>SONET defines four layers: path, line, section, and photonic </li></ul><ul><li>Path layer is responsible for the movement of a signal from its optical source to its optical destination </li></ul><ul><li>Line layers is for the movement of a signal across a physical line </li></ul><ul><li>Section layer is for the movement of a signal across a physical section, handling framing, scrambling, and error control </li></ul><ul><li>Photonic layer corresponds to the physical layer of OSI model </li></ul>
  5. 5. <ul><li>Architecture of a SONET system: signals, devices, and connections </li></ul><ul><li>Signals: SONET(SDH) defines a hierarchy of electrical signaling levels called STSs (Synchronous Transport Signals, (STMs)). Corresponding optical signals are called OCs (Optical Carriers) </li></ul><ul><li>Devices: STS Multiplexer/ Demultiplexer, Regenerator, Add/Drop Multiplexer and Terminals </li></ul>Path Termination Path Termination Line Termination Line Termination Section Termination path line line line ADM ADM regenerator section section section section
  6. 6. <ul><li>Connections: SONET devices are connected using sections , lines , and paths </li></ul><ul><li>Section: optical link connecting two neighbor devices: mux </li></ul><ul><li>to mux, mux to regenerator, or regenerator to </li></ul><ul><li>regenerator </li></ul><ul><li>Lines: portion of network between two multiplexers </li></ul><ul><li>Paths: end-to-end portion of the network between two </li></ul><ul><li>STS multiplexers </li></ul>
  7. 7. SONET FRAMES <ul><li>Each synchronous transfer signal STS-n is composed of 8000 frames. </li></ul><ul><li>Each frame is a two-dimensional matrix of bytes with 9 rows by 90 × n columns. </li></ul>
  8. 8. <ul><li>A SONET STS-n signal is transmitted at 8000 frames per second </li></ul><ul><li>Each byte in a SONET frame can carry a digitized voice channel </li></ul><ul><li>In SONET, the data rate of an STS-n signal is n times the data rate of an STS-1 signal </li></ul><ul><li>In SONET, the duration of any frame is 125 μs </li></ul>
  10. 10. 1. Point-to-point network : 2. Multipoint network :
  11. 11. Ring Network: UPSR <ul><li>Unidirectional Path Switching Ring (UPSR) </li></ul>
  12. 12. Ring Network: BLSR <ul><li>Bidirectional Line Switching Ring (BLSR) </li></ul>
  13. 13. Mesh Network <ul><li>Ring network has the lack of scalability </li></ul><ul><li>Mesh network has better performance </li></ul>
  14. 14. SONET Advantages <ul><li>Reduced network complexity and cost </li></ul><ul><li>Allows transportation of all forms of traffic </li></ul><ul><li>Efficient management of bandwidth at physical layer </li></ul><ul><li>Standard optical interface </li></ul><ul><li>De-multiplexing is easy. </li></ul>
  15. 15. SONET Disadvantages <ul><li>Strict synchronization schemes required </li></ul><ul><li>Complex and costly equipment as compared to cheaper Ethernet </li></ul>
  17. 17. INTRODUCTION <ul><li>Standard for interfacing optical networks </li></ul><ul><li>Simple multiplexing process </li></ul><ul><li>SDH is basically the international version of SONNET </li></ul><ul><li>SONNET is NORTH AMERICAN version of SDH </li></ul>
  18. 18. SDH frame structure <ul><li>STM-1 frame is the basic transmission format for SDH </li></ul><ul><li>Frame lasts for 125 microseconds </li></ul><ul><li>It consists of overhead plus a virtual container capacity </li></ul>
  19. 19. SDH network elements <ul><li>Regenerator (Reg.) </li></ul><ul><li>Terminal Multiplexer (TM) </li></ul><ul><li>Add/Drop Multiplexer (ADM) </li></ul><ul><li>Digital Cross Connect (DXC) </li></ul>
  20. 20. REGENERATOR It mainly performs 3R function: 1R – Reamplification 2R – Retiming 3R – Reshaping It regenerates the clock and amplifies the incoming distorted and attenuated signal. It derive the clock signal from the incoming data stream. STM-N STM-N Regenerator
  21. 21. Terminal Multiplexer (TM) It combines the Plesionchronous and synchronous input signals into higher bit rate STM-N Signal. Terminal Multiplexer STM-N PDH SDH
  22. 22. Add/Drop Multiplexer (ADM) STM-N STM-N PDH SDH Add / Drop Multiplexer
  23. 23. Digital Cross Connect (DXC) STM-16 STM-4 STM-1 140 Mbit/s 34 Mbit/s 2 Mbit/s STM-16 STM-4 STM-1 140 Mbit/s 34 Mbit/s 2 Mbit/s Cross - Connect
  24. 24. TYPICAL LAYOUT OF SDH LAYER <ul><li>General view of Path Section designations </li></ul>SDH multiplexer SDH Regenerator # Cross- connect SDH multiplexer SDH SDH SDH PDH ATM IP Regenerator Section Regenerator Section Multiplex Section Multiplex Section Path
  25. 25. Network Configurations <ul><li>Point to Point </li></ul><ul><li>Point to Multipoint </li></ul><ul><li>Mesh Architecture </li></ul><ul><li>Ring Architecture </li></ul>
  26. 26. SDH Advantages <ul><li>Allows multi-network internetworking </li></ul><ul><li>SDH is synchronous </li></ul><ul><li>Allows single stage multiplexing and de-multiplexing </li></ul>
  29. 29. <ul><li>Multiple channels of information carried over the same fibre, each using an individual wavelength </li></ul><ul><li>Dense WDM is WDM utilising closely spaced channels </li></ul><ul><li>Channel spacing reduced to 1.6 nm and less </li></ul><ul><li>Cost effective way of increasing capacity without replacing fibre </li></ul><ul><li>Allows new optical network topologies, for example high speed metropolitian rings </li></ul>Wavelength Division Multiplexer Wavelength Division Demultiplexer  1 A  2  3 B C  1 X  2  3 Y Z  1  2 +  3 Fibre
  30. 30. <ul><li>ITU Recommendation is G.692 &quot;Optical interfaces for multichannel systems with optical amplifiers&quot; </li></ul><ul><li>G.692 includes a number of DWDM channel plans </li></ul><ul><li>Channel separation set at: </li></ul><ul><ul><li>50, 100 and 200 GHz </li></ul></ul><ul><ul><li>equivalent to approximate wavelength spacings of 0.4, 0.8 and 1.6 nm </li></ul></ul><ul><li>Channels lie in the range 1530.3 nm to 1567.1 nm (so-called C-Band) </li></ul><ul><li>Newer &quot;L-Band&quot; exists from about 1570 nm to 1620 nm </li></ul><ul><li>Supervisory channel also specified at 1510 nm to handle alarms and monitoring </li></ul>
  31. 31. Optical Spectral Bands
  32. 32. Transmitters DWDM Multiplexer Power Amp Line Amp Line Amp Optical fibre Receive Preamp DWDM DeMultiplexer Receivers <ul><li>Each wavelength behaves as if it has it own &quot;virtual fibre&quot; </li></ul><ul><li>Optical amplifiers needed to overcome losses in mux/demux and long fibre spans </li></ul>
  33. 33. <ul><li>THE ERBIUM DOPED FIBER </li></ul><ul><li>AMPLIFIERS (EDFA) </li></ul><ul><li>MULTIPLEXERS </li></ul><ul><li>DEMULTIPLEXERS </li></ul><ul><li>ADD/DROP MULTIPLEXER </li></ul><ul><li>OPTICAL SWITCH. </li></ul>
  34. 34. DWDM Advantages <ul><li>Greater fibre capacity </li></ul><ul><li>Easier network expansion </li></ul><ul><ul><li>No new fibre needed </li></ul></ul><ul><ul><li>Just add a new wavelength </li></ul></ul><ul><ul><li>Incremental cost for a new channel is low </li></ul></ul><ul><ul><li>No need to replace many components such as optical amplifiers </li></ul></ul><ul><li>DWDM systems capable of longer span lengths </li></ul><ul><ul><li>TDM approach using STM-64 is more costly and more susceptible to chromatic and polarization mode dispersion </li></ul></ul><ul><li>Can move to STM-64 when economics improve </li></ul>
  35. 35. DWDM Disadvantages <ul><li>Not cost-effective for low channel numbers </li></ul><ul><ul><li>Fixed cost of mux/demux, transponder, other system components </li></ul></ul><ul><li>Introduces another element, the frequency domain, to network design and management </li></ul><ul><li>SONET/SDH network management systems not well equipped to handle DWDM topologies </li></ul><ul><li>DWDM performance monitoring and protection methodologies developing </li></ul>
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