Optical Fiber Training

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Optical Fiber Networks By

Dr. Muhammad Khalil Shahid

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Optical Fiber Networks Agenda Basics of optical fiber communication system Advantages and disadvantages of O F transmission Pre SDH System SDH System DWDM System ONU/OLT 3

Important Terms/Definitions Wavelength:  

The distance between two successive peaks of a wave The length of the light wave, which determines its color. Common units of measurement are the micron, the nanometer (10 -9)

Bandwidth:  

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The measure of how quickly you can move information from one point to another (bits/s) It's similar to roadways - a four-lane highway can carry more traffic than a two-lane highway.

Bit:  A bit is a binary digit, taking a value of either 0 or 1. For example, the number 10010111 is 8 bits long dB/dBm:  loss/gain is measured in dB, it is a logrithmic ratio dB = 10 log10 (P1/P2)  dBm is a power level above I milli Watt, dBm = 10 log (power / 1 mW)

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General Communication System

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Optical Communication System

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Telecommunication bands Optical telecommunication in the near & short infrared is technically often separated Or

O-band 1,260–1,360 nm ---------- Original E-band 1,360–1,460 nm ---------- Extended S-band 1,460–1,530 nm------------- Short wavelength C-band 1,530–1,565 nm----------- Conventional L-band 1,565–1,625 nm------------ Long Wavelength U-band 1,625–1,675 nm-----------Ultra long wave length

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Optical Windows

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Optical Fiber Cable

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Optical Fiber Cable

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FIBER Cable CONSISTS OF Core Innermost region of the fiber  Used to transmit the light 

Cladding 

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prevented the light from leaking out of the core by reflecting the light within the boundaries of the core.

Concept Of Reflecting 

 

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The angle at which light is reflected is dependent on the refractive indices of the two materials . In our case, the core and the cladding The lower refractive index of the cladding (with respect to the core) causes the light to be angled back into the core

Total Internal Reflection

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Refractive Index  

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The refractive index of a medium is a measure for how much the speed of light is reduced inside the medium For example, typical Soda Lime Glass has a refractive index of 1.5, which means that in glass, light travels at 1 / 1.5 = 0.67 times the speed of light in a vacuum

Transmission of Optical Signals in Optical Fibers

n>n1 Incident angle > Critical Angle Total Internal Reflection

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Types of Fibers Single-Mode Step Index

Multi-Mode Step Index

 Multi-Mode Graded Index

 Single Mode Graded Index

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Types of Fibers Single-Mode: Have only one wavelength Laser diode is used as optical source Uses for long haul transmission and AN

Multi-Mode Have thousands of wave lengths LED is used as optical source Uses in high speed LAN Cheaper fiber  Cheaper system

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Types of optical fibers 

 

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G.652: A single-mode optical fiber that has a nominal zero-dispersion wavelength in the 1310nm transmission region. (dispersion un-shifted fiber) G.653: Dispersion-shifted fiber; zero dispersion at 1550nm transmission region G.655: Non-zero dispersion fiber; used in 1550nm transmission region. Less dispersion coefficient, dispersion limited transmission distance can be hundreds of km

SMF Loss

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Fiber Type

G.652

G.653

G.655

Typical loss value (1310 nm)

0.3 dB/km ~ 0.4 dB/km

-

-

Typical loss value (1550 nm)

0.15 dB/km ~ 0.25 dB/km

0.19 dB/km ~ 0.25dB/km

0.19 dB/km ~ 0.25 dB/km

Working window

1310 nm and 1550 nm

1550 nm

1550 nm

Advantages of Optical Fiber Communication 1) Large Bandwidth… more Data 2) Small Physical Size 3) Light Weight 4) Electrical Isolation / Non Conductor 5) Immunity to Interference 6) Immunity to Cross Talk 7) Signal Security 8) Low Transmission Loss 9) Flexibility 10)Low Cost /bit(Installation , Maintenance and Bandwidth)

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Advantages of Optical Fiber Communication 12) High-Quality Transmission BER:

Typically 10-09 to 10-11 & 10-12 for Optical Fiber Medium

BER:

Typically 10-05 to 10-07 for Copper and Microwave Media

13) Environmental Stability -Low temperatures as – 20 to – 40 Celsius increase in attenuation in optical fiber, while in copper cables temperature has continuous effects) -Lower Corrosion Rates

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Main Disadvantage Of Fiber Optics



Expensive to install … ROW, labour

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

Dangerous for eyes



More fragile than wire and are difficult to split

Factor Affecting Performance of Optical Fiber Transmission 1)Attenuation (reduction in strength of signal): 

decrease the transmission distance, measure in dB/Km

2) Dispersion 

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Scattering of light…reduce the data rate

Types Of Network Elements (NE)

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

Terminal Multiplexer (TM )



Add/Drop Multiplexer (ADM)



Optical Amplifiers (OA)



Digital Cross Connect (DXC)



Regenerators

Types of Networks 1) Point-to-Point Network

TM

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TM

2) Point-to-Multi Point Network

TM

TM

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TM

ADM

ADM

TM

TM

3)Ring Network

ADM-1

ADM-4

ADM-2

ADM-3

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4) Mesh Network

ADM ADM

ADM

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ADM

ADM

5) Composite Network

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Optical Fiber Systems

PDH (Plesiochronous Digital Hierarchy)  SDH (Synchronous Digital Hierarchy)  DWDM (Dense Wave Division Multiplexing) 

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Synchronous & Plesiochronous ? All the NEs use the same clock and are synchronized with the one clock source (PRC) in Synchronous operations Plesiochronous: Plesio means “ Nearly”. If two networks need to inter-work, their clocks may be derived from two different PRCs. Even if these clocks are extremely accurate, there is always a small frequency difference among them.

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PDH 

Pre SDH Standard



3 standards..European, Japanese, North America



European Standard in Pakistan



Complex Multiplexing structure



Weak monitoring

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PDH Data Rates PCM…… 64Kbps  E1……… 2.048 Mbps (30 x64 Kbps)  E2……… 8.448 Mbps  E3……… 34.368 Mbps  E4……… 139.264 Mbps  E5……… 565 Mbps 

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PDH Standards & Rates European Standard

Japanese Standard

E5 565Mb/s E4

x4 139Mb/s

E3

x4 34Mb/s

E2

x4 8Mb/s x4 2Mb/s

E1

1.6Gb/s x4 400Mb/s

274Mb/s

x4 x6

100Mb/s x3

45Mb/s

32Mb/s x5

J2

T3

x7 6.3Mb/s

6.3Mb/s x4

J1 36

North American Standard

x4 1.5Mb/s

T1

T2

Adding & Dropping in PDH

Optical

140/34 Mb/s E4 34/8

Electrical 8/34

E3

De-multiplexing

Optical

E4

E3

E2 8/2 Mb/s

E2

E1

E 1 2 Mb/s

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34/140 Mb/s

2/8 Mb/s

Multiplexing

Limitations of PDH Impossible to interconnect three Incompatible PDH standards  No worldwide optical interface standard  Week Monitoring due to insufficient capacity for network management  No direct extraction of lower order signal  Lower data rates for current and future demands 

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SDH  



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Synchronous Digital Hierarchy SDH is a hierarchical set of digital transport structures, standardized for the transport of suitably adapted payloads over physical transmission networks An integrated transmission network managed by a powerful network management system

SDH Bit Rates – STM-1: 155.52 Mbps – STM-4: 622.08 Mbps – STM-16: 2.488.32 Gbps – STM-64: 9.95 Gbps – STM-256: 40 Gbps

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SDH Signal Rates STM-N

Line Rate E1 (Mb/s) Capacity

E3 Capacity

E4 Capacity

N=1

155.52

63

3

1

N=4

622.08

252

12

4

N=16

2488.32

1008

48

16

N=64

9953.28

4032

192

64

N=256

39813.12

16128

768

256

* STM-0 is not SDH signal rate, however, it is equal to SONET basic rat

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SDH Network Elements Four Types

ADM:

Add Drop Multiplexer

TM:

Termination Multiplexer

DCS:

Digital Cross Connect

REG:

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Repeater (Regenerator)

Adding & Dropping in SDH SDH: Direct & Simple to add/drop electrical signal

Optical Interface

ADM

2 Mb/s

Electrical Signal

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Optical Interface

Advantages of SDH 

More Capacity



Easy to interconnect different systems



simple and direct adding or dropping of electrical signals

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

Network Management System (NMS)



Flexible and self-healing networks (protection)

Advantages of SDH 

All current PDH signals can be transmitted within the SDH except 8 Mb/s (E2) which has no container.



A reduction in the amount of equipment & an increase in network reliability.



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Compatible….PDH, ATM, DQDB

Disadvantages of SDH Lower Bandwidth utilization  Complicated SDH equipments due to variety of management traffic types and options  Software based..vulnerable to computer viruses, software bugs, configuration problems, etc.  Direct add/drop needs pointer, which make it complex and introduce jitter  Can’t carry E2 due to un-availability of container. 

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SDH Terminology SDH refers to the rates and formats specified by ITU-T for synchronous data transmission over fiber optic networks. Few Common Standards of SDH ITU-T G.707: Network Node Interface for SDH  ITU-T G.781: Structure of Recommendations on Equipment for SDH  ITU-T G.783: Characteristics of SDH Equipment Functional Blocks  ITU-T G.803: Architecture of Transport Networks Based on SDH 

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SDH Frame Structure 1

SOH

3 4 AU-PTR 5

STM-N Payload (including POH)

SOH 9 9×N

261×N 270×N

Block frame structure In units of byte (8 bits) Rate: 8000 frames/s, frame cycle: 125µs

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RS, MS, and Path Overheads Difference among POH, MSOH, & RSOH Repeater Term Mux

Add-Drop Mux

Repeater

Term Mux

POH MSOH RSOH • Path OH – end to end circuit • Multiplex Section OH – multiplexer to multiplexer • Regenerator Section OH – repeater to adjacent node or vice versa 50

Section Overhead (SOH) 

Multiplex Section Overhead (MSOH)



MSOH– supervises each STM-1 of STM-N frame



Regenerator Section Overhead (RSOH)

– RSOH– supervises the whole STM-N frame

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Path Overhead (POH) 

Lower order POH (LPOH)



Higher order (HPOH)

---HPOH and LPOH are used for VC4, VC3, and VC12 monitoring

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SDH Overhead Overview RSOH SOH

MSOH Overhead High Order POH

POH Low Order POH

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STM-1 Section Overhead R S O H

M S O H

A1

A1

A1

A2

A2

B1 D1

 

 

E1 D2

 

B2

AU-PTR B2 K1

B2

A2

J0





F1 D3





R O w S

K2

D4 D7

D5 D8

D6 D9

D10 S1

D11

D12 E2

M1 9 Columns

9





 Domestic Use

 Transmission Media Usage Blank indicate Future Use 54

Frame Time=125µs

Payload 

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where services are put in the STM-N frame 2M, 34M or 140M information is packed and put in the payload. It is then carried by STMN signal to send over SDH nodes If we take STM-N frame as a truck, the payload section can be looked as the carriage of the truck

Administrative Unit Pointer (AU-PTR) 

Locate lower rate signal inside a higher rate signal of a STM-N frame (payload).



comprises of 9 bytes



The address range inside which the VC-4 is able to float starts right after the AU pointer block & extends until address 782 in the next STM-1 frame

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AU-PTR AU-4 pointer addresses only every 3rd payload byte.  Last 3 bytes (H3) of AU-PTR are provided as additional transmission capacity in order to equalize clock difference.  Justification operation (positive or negative) can be carried out no more than once in every 3 rd STM-1 frame.  AU-PTR bytes: H1, Y, Y, H2, 1, 1, H3, H3, H3  H1=N N N N S S I D; H2=I D I D I D I D 

*

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10 bit pointer value indicated by I & D bits

Mapping (Mode & Structure) Low Rate SDH → High Rate SDH: Byte Interleave  PDH → STM-N: Synchronous Multiplexing & Flexible Mapping – 140M→STM-N – 34M→STM-N – 2M→STM-N – No container for E2 (8 Mbps) 

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Container Container is an information structure, mainly incharge of adaptation functions so that commonly used PDH signals can occupy fixed space  ITU-T G.709 recommendations have stipulated 5 kinds of standard containers: C-11, C-12, C-2, C-3 & C-4 

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Container (C-4) C-4 container is 260x9 bytes in dimension (2340 bytes or 18720 bits)  Actual bits required by E4 signal are 139.264/8000=17408 bits  Remaining extra bits are used for clock alignment, justification, opportunity bits, justification control bits, & overhead bits. 

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Container (C-3) C-3 container is 9x84 bytes (756 bytes or 6048 bits)  Only 3xC-3 (3x6048 bit) of maximum can be transmitted in one STM-1  Actual space required by E3 signal is 34.368 Mbps / 8000 = 4296 bits  The reason for over capacity is a recommendation by ITU-T specifying that the transmission of a 44.736 Mbps (T3) signal must also be carried out in container C-3. (44.736 Mbps/8000=5593 bits which is still less than 6048 bits. 

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Container (C-12) C-12 container is 34 bytes or 272 bits in size.  Actual space required by E1 signal is 2.048 Mbps/8000=256 bits.  Over capacity bits include clock alignment, justification opportunity bits, justification control bits, & overhead bits.  63 E1s can be transmitted through one STM-1. 

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Virtual Container 

The digital flow from the standard container combined with path overhead forms a virtual container (VC). C-4 + POH (9 bytes) = VC-4 (9x261 bytes) C-3 + POH (9 bytes) = VC-3 (9x85 bytes) C-12 + POH (1 byte) = VC-12 (35 bytes)



It is the most important information structure in SDH which supports path layer connection.

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AU & TU 

The Administration Unit (AU) is an information structure that performs adaptation functions for the high order path layer and multiplexing segment layer. AU-4 = AU-PTR + VC-4



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The Tributary Unit (TU) is an information structure that performs adaptation functions for the low order path layer and high order path layer. TU-3 = VC-3 + PTR (3 bytes) TU-12 = VC-12 + PTR (one byte)

TU-3 Pointer

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

Consists of 3 pointer bytes H1, H2, H3



TU-3 = VC-3 + 3 bytes pointer

TU-12 Pointer 

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TU-12 = PTR (one byte) + VC-12 (35 bytes)

TUG and AUG TUG-3 = TU-3 + 6 Justification Bytes TUG-2 = 3 x TU-12 TUG-3 = 7 x TUG-2  One or more AU with fixed locations in the STMN frame form an Administration Unit Group (AUG). A single AU-4 can form one Administration Unit Group (AUG). 



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AUG is useful for the AU-3 multiplexing, but meaningless for AU-4 multiplexing.

Mapping

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

A process used when tributaries are adapted into Virtual Containers (VCs) by adding justification bits and Path Overhead (POH) information



Its essence is to make the various tributary signals synchronized with related virtual containers so that VC can be an independent entity in the transmission, multiplexing and cross connection

Alignment This process takes place when a pointer is included in a Tributary Unit (TU) or an Administrative Unit (AU), to allow the first byte of the Virtual Container to be located.  By setting the pointer, it can provide a flexible and dynamic method for alignment of VC in the unit (TU or AU-4) frame. 

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Multiplexing

70



This process is used when multiple lower-order path layer signals are adapted into a higherorder path signal, or when the higher-order path signals are adapted into a Multiplex Section.



This type of multiplexing comes synchronous multiplexing category

under

Stuffing When tributary signals are multiplexed & aligned, some spare capacity is required in SDH frames to provide space for various tributary rates  This space capacity is filled with "fixed stuffing" bits that carry no information, but are required to fill up the particular frame. 

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Mapping & Multiplexing procedures x3 Multiplexing

x3 Multiplexing

AU PTR

xN STM-N

LO POH

x1 AUG-4

xN Multiplexing

AU-4

VC-4

TUG-3

TUG-2

TU-12

TU PTR HO POH x7 Multiplexing

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VC-12

C-12

2Mb/s

Code rate adjustment

Multiplexing procedure of 140M into STM-1 11 140M

Rate adjustment/ packing

C4

9 260 1 125us

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P O H

Add POH for supervising/ packing

1

1

VC4

Next page

9 125us

261

•

C-4 (Container-4): standard information structure for 140M signal.

•

VC-4 (Virtual Container-4): standard information structure related to C4, supervising real time performance of the loading 140M signal.

Multiplexing procedure of 140M into STM-1 1 10 9 1 Pointer AU-PTR AU-4 alignment

270

270

1 Add SOH

AU-PTR

270

1

RSOH

1

Payload

MSOH

STM-1

9 9 •

AU-4 (Administrative Unit-4): information structure related to VC4.

•

Mapping way: 140MC4 VC4AU-4AUGSTM-1 * only one 140Mbps signal can be carried in STM-1.

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Multiplexing procedure of 34M into STM-1 1 34M

Rate adjustment/ packing

1 P

Add POH for supervising/ packing

C3

O

VC3

Next page

H

9 1

•

125us

84

9 1

125us

85

C3 (Container 3): standard information structure for 34M signal.

•

VC3 (Virtual Container 3): standard information structure related to C3, supervising real time performance of the loading 34M signal.

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Multiplexing procedure of 34M into STM-1 1 1 First level pointer alignment

H1 H2 H3 TU-3

86

1 H1 H2 1 Fill in H3 TUG-3

the gap 9

• • • •

76

86

x3

1

P O R R H

Byte interleave

R 9

261

1

VC4

9

TU3 (Tributary Unit 3): standard information structure related to VC3, finishing the first level pointer alignment. TUG3 (Tributary Unit Group 3): standard information structure related to TU3. Mapping way: 34MC3VC3TU3TUG3; 3*TUG3VC4AU-4AUGSTM-1 3 x34M can be multiplexed in one STM-1.

Multiplexing procedure of 2M into STM-1 125us Basic frame 1 4 1 Rate 速率 adjustment

适配

C12

Add POH for supervising

9 •

POH 1

4

1

4

1

VC12

First level pointer alignment

1

TU12

9

Next Page 9

C12 (Container-12): standard information structure for 2M signal,

finishing rate adjustment, 4 basic frame forming a multi-frame. (Virtual

Container-12); standard information structure related to C12, supervising real time performance of the loading 2M signal.

•

VC12

•

TU12 (Tributary Unit 12): standard information structure related

to VC12, finishing the first level pointer alignment of VC12. 77

Multiplexing procedure of 2M into STM-1 x3

Byte interleave

12

1

1

x7

Byte 字节 interleave 间插

TUG2

86

1 R R

TUG3

9

TUG-2 (Tributary Unit Group-2) •

TUG-3 (Tributary Unit Group-3)

2MC12VC12TU12; 3xTU12TUG-2; 7xTUG-2TUG-3; 3xTUG3VC4AU-4AUGSTM1

•

3x7x3=63x2M signals can be multiplexed in STM-1. Multiplexing structure of 2M signal is 3-7-3 structure.

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79

A1 & A2 Bytes Framing bytes A1, A2 • Used to identify the start of frame • A1=F6H & A2=28H •Generate Alarms OOF, LOF

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A1 & A2 Bytes Framing

Find  A1, A2

Y

N

OOF

LOF

Next  Process

81

AIS

Regenerator Section Trace Byte: J0 or C1

82



STM identification byte



Every STM-1 frame is assigned an identification number before being multiplexed to an STM-N.



It makes sure that regenerator section of sending and receiving points keep continuously connecting.

User Channel Byte: F1

83



Provide a 64 kb/s data or voice channel for local maintenance purpose to network operator.



Only transmitted in STM-1 #1 of STM-N signal.

D1~D12 Bytes Data Communication Channel Bytes: D1~D12    

These 12 bytes are provided for the transport of monitoring & control data in Network Management System. D1-D3 belongs to RSOH, bandwidth is 3x64 kb/s D4-D12 belongs to MSOH, bandwidth is 9x64 kb/s D1-D12 are transmitted in STM-1#1 of STM-N only.

DCC Channel

NMS

84

OAM Massages: performance, alarm, operation commands etc.

Order Wire bytes: E1 & E2 Provide 64 kb/s digital telephone channels  E1 transmit RS order wire message  E2 transmit MS order wire message (express channel)  Only present in STM-1#1 of STM-N 

85

B1 & B2 Bytes Bit Interleaved Parity 8 (BIP-8) byte: B1  Regenerator section error code monitoring  Detect unit is bit block  B1 BBE represented by RS-BBE  Only transmitted in STM-1 #1 of an STM-N Bit Interleaved Parity 24 code (BIP-24) byte: B2  Multiplexing section error code monitoring  Detect unit is bit block  B2 BBE represented by MS-BBE  Only transmitted in STM-1 #1 of an STM-N 86

B1 & B2 Bytes  

Verify each bit column Works on Even parity basis

B1: In unit of 1 byte (8 bits) B2: In unit of 3 byte (24 bits)

BIP-8

x1 00110011 x2 11001100 x3 10101010 x4 00001111 B

01011010

11001100 11001100 11001100 01011101 01011101 01011101 BIP-24

11110000 10110000 11110000 01100001 01100001 01100001 0000000

87

0100000

0000000

B1 & B2 Bytes

No.n Fram e

1st

Verify B1, B2 Calculate B1, B2

1st Frame

2nd Frame

Frame 2nd Frame

88

A

B

Tx

Rx

No.n Frame

M1 Byte Multiplex Section Remote Error Indication (MS-REI) byte: M1  A return message from Rx to Tx when Rx find MS-BBE  By evaluating the 3xB2, the M1 byte can report back the number of parity code violations.  MS-REI will be generated in Tx.  M1 byte is one per STM-N frame. Traffic

Rx

Tx Return M1

Find B2 Error: MS-BBE

89

Generate MS-REI

K1 & K2 Bytes Automatic Protection Switching (APS) bytes: K1, K2 (bits:b1-b5)  Used for network multiplex protection switch function  K1 & K2 only transmitted in STM-1 #1 of STM-N  Multiplex Section Remote Defect Indication (MS-RDI): K2 (b6-b8) – Return alarm message from Rx to Tx – Indicate Rx receiving alarm – K2 (b6-b8) value is 110

90

K1 & K2 Bytes Detect  K2 (b6~b8)

N 111 Y Normal  Operation Generate MS­ AIS

Return MS­ RDI

91

Synchronization Status Message (SSM) byte: S1 

SSM indicates the status & quality level of SDH signal



Value indicates quality level of available clock source (b5-b8) 0010 = G.811 = External Clock 0100 = G.812 = Extract from SDH source 1000 = G.812 = Extract from PDH tributary 1011 = G.813 = Internal Clock



Only transmitted in STM-1 #1 of STM-N

92

High Order Path Overhead 1

VC4

261

J1 B3 C2 G1 F2 H4 F3 K3 N1

Structure of High Order Path Overhead

93

1

9

Path Trace Byte: J1 • First byte of VC-4 • Using J1 byte, every path can be assigned a trace. • Required matching at transmit and receive ends. • Set value as needed

94

B3 Byte Path BIP-8 Code • Implements VC-4 transmission performance monitoring

Verify B3

N

• Monitoring principle: BIP-8 even parity • Layered monitoring: B1, B2, B3

Correct Y BBE Next process

95

Signal Label Byte: C2 Indicates the type & composition of multiplexing structure.

Example:  00H means  02H means 3xTUG-3  13H means  12H means

96

unused multiplexing structure is ATM cells C-4

Path Status Byte: G1 • Indicates high order VC transmission status • Report back the fault from path end to path start • It is set in POH of opposite direction HP-REI: Higher Order Path Remote Error indication (sum of receiving error block of VC4)  HP-RDI: High Order Path Remote Defect Indication 

97

TU location indicator Byte: H4 • Indicate the multi-frame types and location of the payload. • For 2M PDH to SDH multiplexing structure, H4 indicates the current frame, which frame of the multi-frame, allowing Rx to find TU-PTR & drop 2M signals. • H4: 00H-03H

98

Other Bytes

99



F2 and F3: Network providers can use it for exchange of data (local maintenance)



K3: APS for high order path



N1: another byte for (maintenance purposes)

network

operator

usage

Low Order Path Overhead VC-12 POH • Location  First byte of each basic frame in a multi-frame  Consist of four bytes • Monitoring VC12 performance during signal transmission

1 1 V5

4 J2

VC12

N2

VC12

K4

VC12

9 500us VC12 Multi-frame 100

VC12

Path status & signal label byte: V5 The first byte of VC12 multi-frame  Pointed by TU-PTR  Monitor error block, signal label, path status – Error block monitoring: b1-b2 – Return path status message:b3, b8 – Signal label: b5-b7 Similar to B3, C2, and G1 

101

Other Bytes

102



J2: Low order path trace byte (VC-12 level)



N2: byte for network operator usage



K4: APS for low order path

Self-Healing Network? It is a network which can automatically resume its loaded services within a very short time in case of fault. Its terminal users do not notice any service interruption.

103

Self-Healing Basic Principle When the working route fails or experience problems, services will be switched to the protecting route automatically within a very short time (<50ms). Redundancy routes are essential for self-healing networks. Protection Path

Working Path

104

Self-Healing Network Classification Classification Based on Topology  Train or Chain Network Service Protection  Ring Network Service Protection  Inter-Ring Service Protection Based on Protection Method  Multiplex Section Protection (MSP)  Path Protection (PP)  Logical Subnet Protection 105

Chain Network Protection Types •

106

1+1 Path Protection

•

1+1 Multiplex Section Protection

•

1:1 Multiplex Section Protection

Chain Network 1+1 Path Protection CS

TR

CS OL

OL

OL

OL

W P Send Together 107

Receive One

TR

Chain Network 1+1 Path Protection At sending end, the STM-N signal is sent simultaneously over both segments of the work and protect.  At receiving side, only one (work or protect) path is selected based on quality. 



108

Send Together Receive One

Chain Network 1+1 Multiplex Section Protection

TR

CS

work route

CS

OL

OL

OL

OL

protect route

TR

work or protect

At sending end, the STM-N signal is sent simultaneously over both segments of the work and protect. At receiving side, only one (work or protect) path is selected based on quality. Send Together Receive One 109

Chain Network 1:1 Multiplex Section Protection Wor k

CS

CS OL

OL

OL

OL

Work

Protectio Protectio nThe 1:1 structure is the subset of the 1:N n (where N=1) structure. It has the capacity to work in the 1+1 structure and to interconnect with the 1+1 structure of the other end. 110

Self-Healing Networks In Multiplexing segment 1:1 protection The working payload is transmitted through the working path while the protection path can be used to carry extra payload which is of inferior class.  When the working path fails, the extra payload on the protection path will be superseded by the working payload according to APS protocol. Thus the working payload is protected. 

 111

Under normal circumstances, 1:1 becomes 2+0.

Automatic Protection Switch WORK

PS

1

end

source

3

PROTECT

source 7 PS

4 K1,K2 K1

2

WORKING PATH PROTECTION PATH 112

end K2

6

5a

5b

Ring Network Protection

113

Basic Ring Network Protection Types

115



2-fiber Unidirectional Path Protection Ring



2-fiber Bidirectional Protection Ring

Multiplex

Section



4-fiber Bidirectional Protection Ring

Multiplex

Section

2-Fiber Unidirectional Path Protection Ring CA

CA

AC

AC

W1

W1

P1

P1

A D P1 W1

B C

D P1

A C

B

W1

switchin g

CA AC CA AC • It adopts 1+1 protection mode, the switching criteria is PATH-AIS, & APS protocol is not needed. • At the source NE, the payload is send to the working path and protection path simultaneously. The destination NE detect and compare the coming signal from both paths, then determine to receive the payload of better quality. 116

2-Fiber Bidirectional MS Protection Ring 2 fiber: Two fibers between a pair of nodes  Bi-direction: Service between two NEs use the same section of the network and are transmitted by reverse direction  Multiplexing Section: Protection based on MS, protect the payload part, use APS protocol for protection. 

117

Working Principle S1/P2 A D

B C

118

S2/P1

Working path S1 & S2; under normal situations, service are transmitted over working path. The first half of one fiber is working path. Taking STM-16 as an example, 1-8 AU4 are used for working path.

Working Principle Protecting Path S1/P2 A D

B C

119

S2/P1

P1 & P2; services transmit along protection path after switch over. The last half part of the fiber is used as protecting path. Taking STM-16 as example, 9-16 AU4 are used as protecting path.

Working Principle S1/P2 A D

B C

120

S2/P1

Relationship between working & protecting paths The protecting path of one direction protect the working path of the other direction, i.e, P1 protects S1, & P2 protects S2.

Working Principle CA Rx

AC Tx S1/P2

A D

S2/P1 B

121

to

Service AC is sent in S1 through path A->B>C Service CA is sent in S2 through path C->B>A

C

CA Tx

Use S1 & S2 transmit services.

AC Rx

P1 and P2 can be used to send extra service now.

Switching Conditions Auto Switch Conditions: LOS, LOF, MS-AIS, Signal Degrade

122

Switching Procedure CA Rx

AC Tx S1/P2 A

S2/P1

D

B C

CA Tx 123

AC Rx

Switch ： If the fiber between B and C is broken, switching occurs in B and C B node: service AC crosses from S1 to P1, and sent through A->B>A->D->C C node: service CA crosses from S2 to P2, and sent through C->D>A->B->A

Features of 2 Fiber Bidirectional MSP Ring 

Advantages: Time slots between two nodes can be reused, thus increasing the transmission capacity. Standby path P1 and P2 can be used to transmit extra services of inferior class.



Disadvantages: longer switching time due to APS protocol. Numbers of maximum nodes supported by APS is limited to 16.



Transmission capacity: (k/2) x STM-N nodes).

124

(k=no. of

Comparison of protection schemes

125

Protection Type

2f Unidirectional PP Ring

2f Bidirectional MSP Ring

4f Bidirectional MSP Ring

No. of Nodes

K

K

K

Line Speed

STM-N

STM-N

STM-N

Transmission Capacity

STM-N

K/2*STM-N

k*STM-N

APS Protocol

No

Yes

Yes

Switching Time

<30ms

50-200ms

50-200ms

Cost

Low

Medium

High

System Complexity

Simple

Complex

Complex

Field of Application

Relay Networks (Centralized Services)

Long Distance Networks (Distribution Services)

Long Distance Networks (Distribution Services)

Subrack Power consumption: < 350W; A single subrack weighs 18.6kg 858mm (height) * 440mm (width) * 290mm (depth)

126 126

SDH Cards P

P

P

P

X

X

S

S

S

P

P

S

Q

Q

L3 Q

C

C

16 16 P

Q

Q

C

1

1

1

S

S

Q

1

1

C

4

127 127

Interface Board 

PDH processing board in IU slot

PD1

32-channel E1

electrical processing board

PQ1

63-channel E1

electrical processing board

PL3

3-channel E3/T3

electrical processing board

PQ3

12-channel E3/T3

electrical processing board

128 128

SDH Interface Unit S16: 1-channel STM-16

optical interface board

SD4: 2-channel STM-4

optical interface board

SL4: 1-channel STM-4

optical interface board

SQ1: 4-channel STM-1

optical interface board

SD1: 2-channel STM-1

optical interface board

SL1: 1-channel STM-1

optical interface board

SP8: 8-channel STM-1

signal process board 129

129

Indicator  Green: 5 times/s 1 time/2s 1 time/4s

 Red: Constantly off 3 times/s 2 times/s 1 time/s Constantly on

Running Indicator not in service normal off-line status

Alarm Indicator no alarm Critical alarm Major alarm Minor alarm CPU self-check failed

130 130

Alarms Critical Alarms Emergency situation like fiber cut or some system failure, Need immediate attention, interrupt services  Major Alarms: Need attention, may interrupt some services  Minor Alarms: No interruption in service 

131

Why DWDM? Increase in Band Width Demand

• Growth of voice traffic • IP traffic • Data traffic Telemedicine Video conferencing Remote education Mobile telephony

132

Dense Wavelength Division Multiplexing “DWDM” An optical technology used to increase capacity over existing fiber cables  transmitting multiple signals simultaneously at different wavelengths on the same fiber  one fiber is transformed into multiple virtual fibers. 

133

DWDM concept Different

signals

with

specific

wavelengths

are

multiplexed into a fiber for transmission. SDH signal IP package ATM cells

1 2 ┋

134

1  2

n

┉

DWDM Bandwidths → 4×2.5Gb/s →16×2.5Gb/s →32×2.5Gb/s →32×10Gb/s →160×10Gb/s =1.6Tb/s

135

DWDM..Cost Saving

SDH DWDM

Electrical Regenerator Light Amplifier

136

Advantages of DWDM  Transparent transmission  Long haul transmission  High capacity  Use existing optical fibers  High performance-to-cost ratio  Reliability  Easy up-gradation

137

Optical amplifier

OSC

138

OTU Access channels

Access channels

OTU

MUX

DMUX

Application of Amplifiers Demultiplexer

PA

PA: Pre-amplifier (gain 23 db) LA: Line amplifier (gain 30-33 db) BA: Booster amplifier (gain 23 db) 139

Multiplex er LA

BA

Optical supervisory channel TCP/IP

NE3

NE2

GNE1

• OSC Operating wavelength 1510nm • 2Mb/s full management with order NMS (T2000) wire phone • Insert/extract data Information • Two Notypes needofof amplification NMS Information (D1 to D12 Bytes) Order wire (E1 & E2 Bytes)

140

Frame structure of DWDM OSC 0 1 • • • • • •

141

2

3

TS0: TS1: TS2: TS3-TS14: TS15: TS16-TS31:

14 15 16 FAS E1 F1 D1-D12 E2 reserved

31

Cabinet of DWDM 1- Power Box 2- ODF Sub-Rack 3- Equipment SubRack/Interfaces 4- Rack Interface

142

Power Box 2

1

6

7

8

9

3

4

10

5

11

12

Note: 1. -48V ( Ist. Supply source Line); 2. -48V (2nd.Supply source Line); 3. Alarm clearing switch; 4. Sound/light test switch; 5. Indicator; 6. Master switch (the first line); 7. Master switch (the second line); 8. Protection ground; 9. Power ground; 10. Power switch of the upper subrack; 11. Power switch of the lower subrack; 12. PMU board. 143

ODF Sub-Rack 1- Upper ODF (44 interfaces) 2- Middle Sub-Rack (60 interfaces) 3- Lower Subrack (60 interfaces) 144

Upper ODF 4 1 4 2 4 3

3 5

2 9

2 3

1 7

1 1

3 6

3 0

2 4

1 8

1 2

3 7

3 1

2 5

1 9

1 3

3 8

3 2

2 6

2 0

1 4

5 6 7 8 9 1 0

4 1: SCA-RI 4 (Line 3 Fiber)3 4: 2 SCA-TO 2 (Line 1 Fiber) 9 3 (From 7 SDH) 1 5 5 to 20: M16I1-M16I16 23 to 38: D16-O1D16-O16 4 3 2(To SDH) 2

0 4 42-43: SC2-RM2-SC2-TM2

145

8

2

1 6

1

4

Middle/Lower ODF

1 18

2 3 4 19 20

21 38

22 23 24 39 40

41 58

146

42 43 44 59 60

5

6

7

8

9

10

11

12

13

14

15

16

17

25 26

27

28

29

30

31

32

33

34

35

36

37

45 46

47

48

49

50

51

52

53

54

55

56

57

Equipment Sub-Rack 1- Optical Conversion Sub-Rack (OCS) 2- Optical Integrated Sub-Rack (OIS) 3- Optical Amplifier Sub-Rack (OAS)

147

ABBRIVIATIONS

1- TWC Transmitting Wave length Conversion Board 2- RWC Receiving Wavelength Conversion Board 3- LWC Line Wavelength Conversion Board(TWC+RWC) 4- M16/D16 16 Channel Multiplexer/De-Multiplexer Board 5- SCA Supervisory Channel Access Board 6- SC1/2 Single/Dual Supervisory Channel Board 7- MR2 Two Wavelength Add/Drop Multiplexer Board 8- SCC System Control & Communication Board 9- OHP Overhead Processor Board 10- WPA Wavelength Pre-Amplifier Board 11- WBA Wavelength Booster Amplifier Board 148

Opti X BWS 320G Opt i cal Conversi on Sub- rack Boards: TWC, LWC, RWC, SCC

T / R W C

149

T / R W C

T / R W C

T / R W C

T / R W C

T / R W C

T / R W C

T / R W C

T / R W C

T / R W C

T / R W C

T / R W C

S C C

OptiX BWS 320G Optical Integrated Sub-rack Data traffic and equipment maintenance interface Power Supply Interface

Data traffic and equipment maintenance interface W P A

W B A

M 1 6

D 1 6

M S 2

S C A

S C 1

S C C

Boards: WPA, WBA, D16, M16, MS1, SCA, SC1, SCC, OHP

150

O H P

X.25 Ethernet BNC F&f RS£232 & RS422 F1 order wire Interface

Opt i X BWS 320G Opt i cal Li ne Ampl i fi er Sub- rack

W P A

151

W B A

W PW W P AB A A

W B M S A 2

S C A

M S S C 2 S S S O C CÉ C H A ¿ A 2 C P Ñ¡

S C A

Boards: WPA, WBA, MS2, SCA, SC2, SCC, OHP

HUAWEI DWDM NETWORK SORAB

KHUZDAR

ADM

ADM

ADM

REG

MASTUNG

REG

BELA

KALARI OLA

A AN M

KOTRI

ADM

D.M. ADM JAMALI

RK LA

OLA

ADM

D.I.KHAN ADM

DADU

AD

OLA

THATTA

OLA

FAZILPUR OLA

AD

M

PESHAWAR (CITY)

D. G

OLA

AD M

ROJHAN

HA

BHAKKAR

MADM

CHOWK QURESHI

MADM

RING 1

NMS ISLAMABAD (IBA-I)

HARNOLI

OLA

OLA

OLA

OLA

ADM

OLA

MADM

SUKKUR

NOORIABAD RANIPUR AD M

HYDER ABAD

NAWAB SHAH ADM

STM-16 RING 7 ADM

MIRPUR KHAS

RING 3

RING 4 MULTAN (C)

OLA

OLA

DHERIKI

OLA

BAHAWALPUR ADM

R.Y.KHAN

MORO

Workstation AD

M

OLA

DERA JATTA

MIAN CHUNNU

ADM

SAHIWAL

LEGEND

ADM

DWDM TERMINAL (OTM)

SANGHAR

MADM

GOJRA MORE Workstation

RING 2

ADM

OLA

FATEHPUR

MADM

2.5 Gb/s ADD/DROP MULTIPLEXER (ADM) 2.5 Gb/s MULTI ADD/DROP MULTIPLEXER (MADM)

OLA

DWDM OPTICAL LINE AMPLIFIER (OLA)

REG

SDH REGENERATOR (REG) EXISTING OPTICAL FIBRE LINK

JHELUM

OLA

FAISALABAD (S/ABAD) OLA

MANAWALA

LAHORE (CTH)

ADM

GUJRAT

AD

M

SIALKOT ADM

LAHORE ADM

152

OLA

FAISAL ABAD

OLA

ADM

ADM

OLA OLA

SARGODHA

MADM

ADM

Workstation

MULTAN

QUAIDABAD

MADM

KARACHI

RING 5

KARACHI (P/CAP)

MARDAN

LAWRENCEPUR N

SHIKARPUR

ADM

ADM

OLA

.K

MADM

Workstation

PESHAWAR AD M

JUMMAN SHAH

KANDHKOT

OLA

AHMADI BANDA

M AD

UTHAL ADM HUB

MACHH

SIBBI

ADM

OLA

REG

STM-16 RING 6

BANNU

SHAHBAZ KHEL

ADM

ADM

QUETTA

ADM

RAW ALPI NDI

USMANI BANDA

REG

ADM

WADH

KALAT

ADM

GUJRANWALA

NORTEL DWDM NETWORK Shikarpur D I KHAN Larkana Khandh Rojhan Kot Jampur KN Shah Kot Dadu Bahadar Sehwan

Kalari

D G Khan Manzoorabad

1883 Kms 2 Ch. x 10 Gb/s 30% Traffic Density

Gharo

Karachi P/Cap Nooriabad

Hyderabad

Morro

Anayatpur Chak 32 Ghotki Sardar

Garh

Ranipur Sukkur

Lawrencepur

153

(13)

OLA

(33)

Islamabad IBA-I

NORTH RING 1650 Kms 2 Ch. x 10 Gb/s 70% Traffic Density

Mandra Jehlum

Gujrat

Khanewal Mian Chunnu Sahiwal Fatehpur

Sialkot Manawala

Gujranwala

Faisal abad

Lahore CTH

LEGENDS ADM

Peshawar City

Nowshera

Kot Addu

Multan Central Lodhran

N.Saeedabad

Karor

Qureshi Chowk

SOUTH RING

Jheruk

ShabazBannu Ahmadi Khel Banda Kohat

REG

(05)

NEW 10G DWDM NETWORK

73 QALAT

13 8

20 6 ADM

KHUZDAR BELA

60

QUETTA(CENT) QUETTA(S/R)

ADM

ADM

SDH RING170 5

UTHAL

12 DM JAMALI 213 M 2ADM 350 ADM AD 16 LARKANA DADU 796 129

ADM

MADM

39

KOHAT

MADM

65

10 NEW MULTAN

MADM

ADM

106

RING 1

MULTAN-2

RAWALPINDI-2

20

M AD

LAHORE- 2 MP KHAS

ADM

HYDERABAD

OKARA

200

R.Y.KHAN

259 ADM

143

96

SARGODHA

LAHORE E/R

35

KHARIN CANTT

RING 2

03 AD M

163

JHELUM

AD M

AD M

110 ADM

ADM

75

SAHIWAL

41

MADM

BAHAWALPUR

AD M

MADM

191

137 23 ADM

FAISALABAD

AD M

145

NMS

174 ADM

22

AD M

NAWAB SHAH

LODHRAN

72

MADM

86

RING 4 256

M

ADM

SUKKUR

A D

MARDAN

CHOWK QURESHI

08

164

GUJRAT

70

76

SIALKOT

ADM

GUJRANWALA

154

02

PESHAWAR -2

ADM

RING 3

AD M

PESHAWAR CANTT

57 ADM

38

60

223

SHIKARPUR

KARACHI M/R

KARACHI-2

BANNU

ADM

10 0HUB 25 407

ADM

ADM

D.I.KHAN

ADM

SDH

ADM

M AD

D.G. KHAN

SIBBI

140

143

ADM

64

RAWAL P INDI

SORAB

ADM

M AD

97

ADM

ADM

ADM

OAN SYSTEM Hardware Structure

OAN basically consists of following components to perform three major functions a) service access, b) transmission and c)network management, 1. 2. 3. 4.

155

OLT (Optical Line Terminal). ONU (Optical Network Unit). AN-NMS (Access Network-Network Management System). SDH / PDH Transmission System

OAN SYSTEM STRUCTURE

156

Optical line terminal (OLT)   



157

collecting point of various services of the exchange such as voice, data and image provides the network interface of multiple services. As a modularly structured unit, the OLT is composed of multiple service interface modules which are stacked together. The capacity of the OLT can be expanded smoothly by adding the service interface modules, so it is flexible in configuration and expansion.

Optical line terminal (OLT) LAN / WAN

Optical Line Terminal (OLT) belongs to the service node equipment

of

the

ATM

access

network. It is connected with the service node through service node interface to

IDC

Cable TV DDN/FR

perform the service access

Internet

of the access network.

NMS PSTN/ ISDN

158

OLT

B a y Ne tw o rks

INTERFACES AVAILABLE AT OLT Following interfaces are available at OLT.     

159

E1 leased line interface conforming to ITU-T G703 ISDN services,V5.2 if connected to ISDN exchanges. DDN connection. Internet ISP connection, Broadband services (ATM switch, ATM server etc.) CATV service

OPTICAL NETWORK UNIT (ONU)

The Optical Network Unit (ONU) belongs to subscriber equipment of the access network and provides subscribers with integrated services of voice, data and image.

160

Optical Network Unit (ONU)  1) 2) 3) 4) 5) 6)

161

OPTICAL ACCESS NETWOK ONU includes SIP module, optical transmission module, power and environment monitoring module built-in primary power supply, main distribution frame batteries

INTERFACES PROVIDED BY ONU 

Z interface. (POTS).



U interface. ISDN BRI (2B+D).ISDN PRA (30B+D).



Nx64kbps or subrate interface of V.35/V.24 to provide various data services for subscribers.



E1 interface to provide 2M leased line through coaxial cable.



CATV signal through coaxial cable, connected to TV sets at subscribers



162

10M/100M Ethernet interface

PSTN INTERFACE TO OLT ONU

ONU

ODN

ONU

ONU

163

OLT

EXCHANGE V5 Interface or STE

Voice and ISDN Services Access POTS

LAN

CID

Router 2B+D/ 30B+D

Centrex

ONU LE

V5.2

SDH

OLT

ONU 2B+D

ONU 2B+D

Video phone

NT1+TA V.24

NT1 G4 FAX

Digital phone

Full access of POTS and ISDN services.

164

POTS

Internet

Data Services Access 2B1Q

OLT

ONU

DDN Node 2B1Q SDH 2M

(V.24/V.35) DTU 2.4~64kbps

N64kbps (V.35/E1) MTA 2.4~128kbps 2B1Q (V.24/V.35) 64kbps (V.24/V.35) 2.4~19.2kbps (V.24)

E1 ( G.703 ) 64K ( V.24,V.35 ) N64K ( 1 N 31, V.35 ) Sub-rate ( 2.4/4.8/9.6/19.2/48K, V.24 ) 165

2M

MSAN (ZXA10-C) POTS

PSTN/ISD N

DDN

Core network IP

ISDN

155M/622M/2.5 G O L T

ZXA10 S300

MSTP

DDN

ZXA10 O N S200 U

FE/GE FE/GE

ATM

ATM155/62 2

Ethern et

FE/GE/ATM DSLAM

FE/GE

166

ADSL

VDSL

Erbium Doped Fiber Amplifier (EDFA) High gain (10-30 dB)  Large o/p power  Wide operating bandwidths  Low noise (4-8 dB)  Amplifying characteristics independent to bit rate and data format …..Extensive applications in DWDM Systems 

167

EDFA Signal input

Optical splitter ISO

WDM

WDM Optical coupler

TAP Optical isolator PD

EDF Pumping laser

Pumping laser ISO

Signal output

TAP

PD Optical detector

168

EDF

EDF Doped with Er3+  The outer shell has 3 levels structure (E1, E2, E3) E1……ground state E2……metastable state E3……high level state  Pumping lasers are used to excite the EDF  Lots of bound electrons of the Er 3+ are excited from the E1 state to E3 

169

Continue… E3 is not stable and ions are dropped to E2 state (radiation-less decay process)  Particles at E2 state are transited to E1 state via stimulated radiation on passing input optical signal  This results in generation of photons identical to photons of incident signal light  Continuous amplifying is implemented 

170

EDFA principle E3 E2

E1 171

Optical Coupler (WDM) Used for Coupling  Couples the input signal and pumping light  Another name is Optical Mux 

172

Optical Isolator (ISO) For unidirectional light Tx I/P ISO  block the backward ASE in EDF  protects transmitter from interference  Protects the generation of large noise when reflected at the input end and reenters EDF O/P ISO  Prevents the amplified signal from reentering the EDF 

173

Pumping Laser (PUMP) Energy source of EDF  Semiconductor laser with o/p wavelength of 980nm or 1480nm  Pumps the ions from low to high level  Amplification is implemented by transferring energy to signal light 

174

Optical Splitter (TAP) One I/P, two O/Ps  Tap off a small part of the signal for monitoring 

Optical Detector (PD) 

175

Convert the received optical power photocurrent (photoelectric conversion)

into

Gain equalization

Ordinary fiber has narrow flat gain range (15491561)  utilizing heavily aluminum plus erbium-doped optical fiber and Gain Equalization Filter (GEF)  optimizing the optical structure (1525-1560) 

176

. Before gain equalization

After gain equalization

G

G

1525

1565

1525

1565

177 177

Impact of gain flatness in long haul transmission

178 178

Gain locking Drop

>1dB

<0.5dB 179 179

Add

>1dB

<0.5dB 180 180

Application of Amplifiers Demultiplexer

Multiplex er PA

PA: Pre-amplifier (gain 23 db) LA: Line amplifier (gain 30-33 db) BA: Booster amplifier (gain 23 db) 181

LA

BA

Thank you

182