dwdm n sdh

8/13/2019 dwdm n sdh

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SYNCHRONOUS DIGITALHIERARCHY SDH)ANDDENSE WAVELENGTH DIVISIONMULTIPLEXING DWDM)


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Three different hierarchies with different signal formats

Point-to-point transmission\ manual approach to networkmanagement and maintenance.In sufficient capacity for network management.


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The Container (C)Basic packaging unit for tributary signalsSynchronous to the STM-1Bitrate adaptation is done via a positive stuffingprocedure

Adaptation of synchronous tributaries by fixed stuffingbitsBit by bit stuffing

The Virtual Container (VC)Formation of the Container by adding of a POH (PathOverhead)Transport as a unit through the network (SDH)A VC containing several VCs has also a pointer area


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270270 Columns (Bytes)1 9

transmitrow by row

RSOH

MSOH

AU Pointer Payload

(transport capacity)

RSOH: Regenerator section overheadMSOH: Multiplex section overheadPayload: Area for information transport


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The Tributary Unit (TU)Is formed via adding a pointer to the VCThe Tributary Unit Group (TUG)Combines several TUs for a new VC

The Administrative Unit (AU)Is shaped if a pointer is allocated to the VC formed at lastThe Syncronous Transport Module Level 1 (STM-1)

Formed by adding a Section Overhead (SOH) to AUsClock justification through positive-zero-negative stuffing in the AUpointer areabyte by byte stuffing


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NUMBER OF ROWS = 9

NUMBER OF COLUMNS = 9+261=270

NUMBER OF BYTES = 9x270

NUMBER OF BITS = 9x270x8

NUMBER OF BITS / SECOND = 9x270x8x8000

=155520000=155.520 Mbps (STM-1)

BIT RATE OF STM-N = (Nx155.520) Mbps


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Multi-vendor environment (mid span meet)

Synchronous networking

SDH supports multi-point or hub configurations whereas,

asynchronous networking only supports point-to-point

configurations.

Can accommodate both existing and future signals

Simplification (ability to directly drop lower trib)


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Multiplexing several optical signals having different

wavelengths and transmitting simultaneously over a

single fiber is known as Wavelength Division

Multiplexing.

When having to move traffic on spans stretching more

than 800 km, it is obvious to select the DWDM system

over SDH system .

DWDM has wavelength spacing ~0.8nm.


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Faster(Higher Speed per Channel)Thicker (More Channels )

160 Channels possible today

Longer (Link Length before Regeneration)A few thousand km possible today


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OA- Optical Amplifier

OADM- Optical Add Drop Multiplexer


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TRANSPONDER

Converts broadband optical signals to a specificwavelength.Receive Transponders perform reverse function.


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MULTIPLEXER & DEMULTIPLEXER

WavelengthConverted viaTransponder

SeparatedWavelengths

DWDM Multiplexer DWDMDemultiplexer


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OPTICAL ADD DROP MULTIPLEXER

OADM allow flexible add/drop of channels.


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OPTICAL AMPLIFIER(OA)

OA used is Erbium Doped Fiber Amplifier(EDFA) whichamplifies optical signal.


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Capacity Increase

Large aggregate transmission capacityUpgradability

Customer growth without requiring additional fiber to be laid

FlexibilityOptical Add/Drop Multiplexing(OADM)

Optical Cross Connect(OXC)Scalability

The possibility to add new nodes to network

Network TransparencyIndependence of data rate, format and protocols


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dwdm n sdh

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