01 Dwdm Principles 20160612 En

DWDM & OTN Principles

Author: ZTE 10 May 2017

Contents        

Multiplexing Introduction Optical fiber Introduction DWDM Wavelength Allocation DWDM System Architecture DWDM NE Types DWDM Network Modes DWDM Protection OTN Introduction

Multiplexing Introduction

 SDM ( Space Division Multiplexing ) –

It is the simplest form of multiplexing

–

In this more than one physical

over the same circuit by assigning time

transmission path are grouped together.

slots for each device on the line

–

3

 TDM ( Time Division Multiplexing ) –

It allows multiple devices to communicate

uses multiplicity of space channels to

–

It is used of PCM,PDH, SDH and so on

increase capacity for optical

–

Improves line transmission rate to

communication, for example, increasing

increase capacity for optical

fiber cores.

communication

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Multiplexing Introduction

 WDM ( Wavelength Division Multiplexing ) –

It is a kind of frequency division multiplexing

–

It multiplexes a number of optical carrier signals onto a single optical fiber by using different wavelengths (i.e., colors) of laser light

–

It includes Coarse wavelength division multiplexing (CWDM) and Dense wavelength division multiplexing (DWDM)

–

CWDM provides 16 channels on a single fiber in 1271 - 1611 nm transmission windows

–

DWDM provides 40 channels or more in C-Band(1530 -1560 nm). A typical DWDM system would use 40 channels at 100 GHz spacing or 80 channels with 50 GHz spacing

4

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Optical Fiber Introduction

 G.652 Optical Fiber –

be used in the wavelength region between 1310 nm and

1550 nm supporting CWDM and DWDM transmission. G.652.D is Standard Single Mode Fiber (SSMF) dedicated for 10Gbps, 40Gbps and 100Gbps systems. Currently, it is the most popular optical fiber



G.655 Optical Fiber –

defines an optical fiber with performance specified at 1550 nm and 1625 nm with a non-zero chromatic dispersion slope in these wavelength regions, supporting DWDM transmission

Windows

I

II

III

V 1360~1530

Band（nm）

850

1310（O band）

1550（C band）

1600（L band）

Band range（nm）

600~900

1260~1360

1460~1530

1565~1625

1360~1530

Fiber type

multi mode

G.652

G.652/G.653/G.655

G.652/G.653/G.655

All-wave

Application

Short distance, low

Short distance, low bit rate

bit rate

5

IV

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Long distance, high bit rate

（E+S band）

DWDM Wavelength Allocation

 80 Channels in C Band

 40 Channels in C Band

6

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DWDM System Architecture

Optical Transmitter

Channel N

1

┇ Optical Repeater n

λ

n

BA λ s

Optical Monitoring Channel Transmitter

LA λ s λ s

Optical Monitoring Channel R/T

PA λ s

Optical Monitoring Channel Receiver

Network Management System

7

Optical Demultiplexer

Input

λ Optical Repeater 1

Optical Multiplexer

Channel 1

Optical Receiver

Optical Line Amplification

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λ

1

Receiving 1

┇ λ

n

Receiving n

Channel 1 Output Channel N

DWDM NE Types

8

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DWDM Network Modes

 Point-to-point  Link-type  Ring-type  Ring-chain

 Tangent ring  Cross-connect  Mesh

9

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DWDM Protection

10

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OTN Introduction

 Basic Structure of OTN Frame –

OTN (Optical Transport Network) to tell it apart from OTN in the broad sense, ITU-T also uses OTH

Frame alignment

2 3

ODUk

4080

3825

3824

14 15 16 17

OTUk OH

OPUk OH

1

7 8

1

(Optical Transport Hierarchy).

OTUk FEC

Client Signal OPU k Payload

4

Client Signal OPUk - Optical Channel Payload Unit-k ODUk - Optical Channel Data Unit-k OTUk - Optical Channel Transport Unit-k

k=0/1/2/3/4/flex, corresponding to GE/2.5G/10G/40G/100G/Any respectively k=1/2/3/4, corresponding to 2.5G/10G/40G/100G

Frame alignment

11

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OTN Introduction

 OTN Hierarchy Structure and Interface PDH

SAN

ETH

STM-N

OTN

OPUk ODUk (ODUkP and ODUkT) OTUk

OTUkV

OTUk

OCh

OChr

OMSn

–

OPUk: Optical Channel Payload Unit-k

–

ODUk: Optical Channel Data Unit-k

–

OTUk: completely standardized Optical

Channel Transfer Unit –

OPSn

OTSn OTM-n.m

OTUkV

–

with standardized functions

OTM-0.m/ OTM-nr.m,

OCh: Optical Channel with complete

–

functions

12

OTUkV: Optical Channel Transfer Unit

OChr: Optical Channel with simplified functions

–

OMS: Optical Multiplexing Section

–

OPS: Optical Physical Section

–

OTS: Optical Transmission Section

–

OTM: Optical Transfer Module

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OTN Introduction

 The Process of OTN Multiplexing and Mapping Multiplexing

OTM-0.m

1 ≤ i+j+k ≤ n OTMOCGnr.m nr.m

OCCr 1 OChr

i j k

OCCr 1 OChr OCCr 1 OChr

1 ≤ i+j+k ≤ n OCGOTMn.m n.m

–

Mapping 1 1 OTU3[V] 1 ODU3 1 OPU3 1

OCC 1 OCh

1

 j OCC 1 OCh

1

i k

OCC 1 OCh

OTU2[V]

1

OTU1[V]

1

Customer signal 1 ODTUG3

16 4

ODU2 1 OPU2

Customer signal 1 ODTUG2 4

ODU1 1 OPU1

Customer signal

1

It can be seen that there’s sharp trace of SDN/SONET mapping structure in the common OTN multiplexing and mapping structure. It needs more tendency to data services for further development.

–

ODUflex for 1.25G-100G service has been gradually put into application. The capacity of one granularity can be adjusted by software according to requirement. It is an important improvement to elastic network.

13

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OTN Introduction

 OTN Overhead Brief 2

3

2

RES

3

TCM3

4

–

GCC1

4 FAS TCM ACT

5

6

7 MFAS

8

TCM6 TCM2

GCC2

9 SM

11 12 GCC0

TCM5 PM

APS/PCC

FAS: Frame Alignment Signal

–

MFAS: Multiplication Frame Alignment

1 TTI Source node identifier 15 16 Destination node 31 identifier 32 0

OTUk Layer Overhead –

SM: Segment Monitoring

–

GCC0: General Communication Channel 0

–

RES: Reserved Byte

Customized by the operator 63

14

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14

15 RES

16 JC

FTFL

RES

JC

RES

JC

PSI

NJO

RES EXP

RES

Frame Alignment Overhead –

13

TCM4

TCM1

Signal

–

10

2 BIP-8

3

1 2 3 4 5 6 7 8 RES BEI/BIAE BDI IAE

1 1



17



OTN Introduction

 OTN Overhead Brief 1

2

3

1 2

RES

3

TCM3

4

–

GCC1

4 FAS TCM ACT

5

6

7 MFAS

8

TCM6 TCM2

GCC2

9 SM

10

11 12 GCC0

TCM5 TCM1

PM

APS/PCC

14

15 RES

16 JC

FTFL

RES

JC

RES

JC

PSI

NJO

RES

TCM4

EXP

RES

ODUk Layer Overhead –

13

1 TTI

TCMACT:TCM activate/deactivate reconciliation protocol control

17

2 BIP-8

3

channel TCMi: serial connecting and monitoring sub-layer cost

–

FTFL: failure type and failure location report channel

–

PM: channel monitoring

–

EXP: experiment channel

–

GCC1/2: general communication channel 1/2

–

APS/PCC: automatic protection switching and protection

0 15 16 31 32

communication control channel construction

–

15

Customized by operator

OPUk Layer Overhead –

PSI: payload structure identifier

–

JC: adjust control

–

NJO: negative adjust opportunity

Source Node identifier Destination node identifier

63

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1

2 BEI

3

4

5 BDI

–

6

7 STAT

8

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