Transcript An Overview of ITU -T G.709 Monowar Hossain York University An Overview of ITU -T G.709 Agenda   Introduction ITU-T G.709 Frame Structure – – – –  Optical channel Transport Unit Optical.

An Overview of ITU -T G.709
Monowar Hossain
York University
An Overview of ITU -T G.709
Agenda
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Introduction
ITU-T G.709 Frame Structure
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Optical channel Transport Unit
Optical channel Data Unit
Optical channel Payload unit
Forward Error correction
Conclusion
An Overview of ITU -T G.709
Introduction
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Interface for the Optical transport network
(OTN)
Concepts borrowed from SONET/SDH
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Layered structure
In-service performance monitoring
Protection
Other management function
An Overview of ITU -T G.709
Introduction -continued
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Added functionality
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Management of optical channels in the optical
domain
Forward error correction (FEC) to improve error
performance and enable longer optical spans
Provides standardize method for managing
optical wavelengths(channels) end to end
An Overview of ITU -T G.709
Introduction -continued
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Three line Rates is defined
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2,666,057.143 kbs (optical transport unit 1)
10,709,225.316 kbs (optical transport unit 2)
43,018,413.559 kbs (optical transport unit 3)
Constant frame rates
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20.420 kHz (48.971 ms) for OTU1
82.027 kHz (12.191 ms) for OTU3
329.489 kHz(3.035 ms) for OTU3
An Overview of ITU -T G.709
Frame Structure
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Three distinct parts
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Overhead area for operation, administration and
maintenance function
Pay load area for customer data
Forward error control(FEC) block
An Overview of ITU -T G.709
Frame Structure -continued
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Size – 4080 * (4 rows) bytes
Data is transmitted serially beginning at the top
left first row followed by the second row and so
on.
An Overview of ITU -T G.709
Frame Structure -continued
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Size – 4080 * 4 rows
Data is transmitted serially beginning at the top
left first row followed by the second row and so
on.
An Overview of ITU -T G.709
Frame Structure -continued
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Optical Transport Unit (OTU)
An Overview of ITU -T G.709
Frame Structure -continued
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OTU overhead
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Section Monitoring(SM) – 3 bytes
General communication channel (GCCO) – 2 bytes
Reserved (RS) – 2 bytes
An Overview of ITU -T G.709
Frame Structure -continued
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Optical channel Data Unit (ODU) overhead
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Reside 1-14 columns of rows 2,3 and 4
Provide tandem connection monitoring(TCM), end
to end path supervision
Client signal adaptation via the optical channel
payload unit(OPU)
An Overview of ITU -T G.709
Frame Structure -continued
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Optical channel Payload Unit (OTU)
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Contains information to support the adaptation of
client signal.
Located in rows 1-4 of columns 15 and 16.
Definitions very depending on the client signal being
mapped into the OPU payload.
An Overview of ITU -T G.709
Frame Structure -continued
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Forward error control(FEC)
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16 FEC blocks of 16 bytes for the row. 64 bytes/frame
Reed-Solomon RS(255,239) code
Uses 16 byte interleaved codecs.
Can correct up to eight symbol errors(correction mood) and
detect up to 16 symbol errors in the code (detection mood).
Enables communications to maintain acceptable performance
quality in noisy environment.
Provide additional coded data for error checking and error
correction
An Overview of ITU -T G.709
Conclusion
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Meets two requirements
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To cater for the transmission needs of today’s wide
range of digital services
To assist network evolution to higher bandwidths
and improved network performance
A step further toward optical networks
Question?