From SDH to redundant Optical Networking

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From SDH to redundant Optical Networking
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Outline

• Optical fibre types
• SDH (Synchronous Digital Hierarchy)
• DWDM Dense Wavelength Division Multiplexing
• OADM Optical Add Drop Multiplexing
• Redundant Optical Networks
• Concluding remarks

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Multimode Single-mode fibre
Ø 125µm
Ø 50µm
cladding
B2000 MHz.km
Multimode graded index fibre
Ø 125µm
Ø 9µm
cladding
Single-mode fibre
Theoretical Bandwidth of Single-mode fibre is 75
THz
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Types of Single-Mode Fibres

• Conventional Dispersion-Unshifted (ITU G.652)
• Introduced 1983 (1985 at CERN)
• Most widely installed fibre type
• Optimised for transmission at 1310 nm wavelength
• Can be used for single and multi-wavelength
  transmission in the 1550 nm band
• Expensive to use at bit rates of 10 Gb/s and
  higher
• Dispersion-Shifted (ITU G.653)
• Introduced in 1985 for long distances with single
  wavelength
• Cannot be used for multi-wavelength transmission
• Nonzero-Dispersion (ITU G.655)
• Introduced in 1993
• Optimized for high bit rate and DWDM in the 1550
  nm band

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PCR Optical Fibre Node
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S D H
Synchronous Digital Hierarchy
Developed from PDH (Plesiochronous Digital
Hierarchy) both are TDM (Time Division Multiplex)
Systems
the lowest SDH rate STM-1 is 155.52 Mb/s the
lowest SONET rate STS-1 is 51.84 Mb/s
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PDH
2 Mb/s
8 Mb/s
30 ppm
34 Mb/s
20 ppm
2 Mb/s

• Difficult to extract single channels
  (de-multiplexing)
• NO System Management

140 Mb/s
15 ppm
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SYNCHRONOUS DIGITAL HIERARCHIES (SDH)
X4
STM-64
9953280 kbit/s
X4
STM-16
2488320 kbit/s
X4
STM-4
622080 kbit/s
X4
STM-1
155520 kbit/s
lower speed plesiochronous and synchronous
tributaries
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Synchronous Digital Hierarchy
STM-4
STM-16
STM-1
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S D H Add/Drop Multiplexer
ADM
STM-16 west
STM-16 east
140 Mb/s 45 Mb/s 34 Mb/s 2 Mb/s
Digital Tributaries
STM-1 / STM4
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S D H
Multiplex Section Shared Protection Ring
MSSpring
X
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SDH n ?
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80 of Worlds Voice and Data traffic today
via SDH/SONET
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ITU-grid 100 GHz channel spacing
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OADM Optical Add/Drop Multiplexer
OADM
?1, ?2, ?3,...., ?n
?1, ?2, ?3,...., ?n
?3
?3
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OADM
Optical Add Drop Multiplexer
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OADM
Optical Add Drop Filter
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Optical Networking
Courtesy to Stephan Asch/Siemens AG
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Optical Networking
Courtesy to Stephan Asch/Siemens AG
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Optical Networking
Courtesy to Stephan Asch/Siemens AG
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Optical Networking
Courtesy to Stephan Asch/Siemens AG
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Optical Networking
Courtesy to Stephan Asch/Siemens AG
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Optical Networking
few channels few nodes single rings managed dark
fibre
more channels more nodes multiple rings WDM
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Optical Networking
SNMP Management
Site 1
Site 2
Transport Network
Courtesy to Stephan Asch/Siemens AG
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Optical Networking
Bit transparent Channel
Courtesy to Stephan Asch/Siemens AG
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Optical Networking
Communications Center
Gigabit Ethernet Controls
Gigabit Ethertnet Exp.
Real Time Controls
Gigabit Ethertnet Safety
TDM
Bit transparent
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Concluding remarks

• Future Networking will be OPTICAL
• Optical Switches and Optical Cross Connects
  (will) allow full Optical Routing
• Channels bit transparent, latency limited to
  light propagation
• Low initial cost, easy and flexible growth, pay
  as you grow
• Upgrade in service
• Protection switching (typ. 50 ms) and monitoring
• 32 wavelengths max. 8 nodes on a ring
• -48Vdc Supply (battery back up)
• Many vendors (competitive market)
• TERRA BITS PER SECOND ARE NOW POSSIBLE, BUT..

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Optical Routing
http//www.lucent-optical.com/news/
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Trenchwork at PA7 Summer 1999