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Sonet Sdh Dwdm

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SONET/SDH are digital fiber optic transmission standards developed independently in the US and Europe to transmit data at high speeds over fiber optic cables. SONET defines a hierarchy of electrical signaling levels called STS and uses synchronous TDM multiplexing. It can transmit data from 155 Mbps to 2.5 Gbps and supports ring topologies. SONET defines layers for signal transmission including path, line, section and physical layers. SDH is the international version of SONET and uses similar framing and network elements like multiplexers, regenerators and cross-connects to transmit digital signals over fiber optic networks. DWDM further increases fiber capacity by transmitting multiple wavelengths/channels over the same fiber using wavelength division

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

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Sonet Sdh Dwdm

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