optical transport networks

Mar del Plata, Argentina, 31 Aug – 1 Sep 2009

ITU-T Kaleidoscope 2009Innovations for Digital Inclusion

Virgilio [email protected]

Olga [email protected]

OPTICAL TRANSPORT NETWORKS: FROM ALL-OPTICAL

TO DIGITAL

Mar del Plata, Argentina, 31 Aug – 1 Sep 2009 ITU-T Kaleidoscope 2009 – Innovations for Digital Inclusion 2

Outlines

Traditional DWDM based on OTN (Optical Transport Network) ITU-T G.872;

IPoDWDM;

ODN (Optical Digital Network);


Introduction

IP traffic today becomes dominant:New application based on IP (video communication, P2P, etc.);Old application migrate to IP (ex. SS7);IP traffic has overcome capacity of currently used wavelength 10Gb/s;

Today trend/evolution is:Eliminate SDH/SONET layer;Move Transport from Optical to Digital;


Traditional DWDM as an OTN

DWDM is a fully optical network which provides transparency:

only 1R regeneration (optical amplification-equalization and CD compensation); theoretically the signal can be delivered from every ONE to any other.

Traditional (OTN) approach becomes hardly realizable for big network;


IPoDWDM ApproachInsert IP traffic into DWDM without mapping into SDH frame; Integration of DWDM transponders directly into IP switch/router.

IPoDWDM

OTNTransponderTransponder

Transponder

G.709

IP r

oute

rs

Transponder

G.709

IP r

oute

rs

TransponderTransponder

MUX

Colored interface

Gray interface

Transponder


IPoDWDM intelligence

Preemptive traffic protection becomes possible

OTNBER

Corr

ecte

d b

its

Optical Impaiments

FEC Limit

Working path Lost data

Protection p.

POS o

n r

oute

rTra

nsp

onder

IP L

ayer

SD

H/D

WD

M L

ayer

LOF

IP L

ayer

+ G

.709 o

n r

oute

r

IPoDWDM

BER

Corr

ecte

d b

its

Optical Impaiments

FEC Limit

Work path Protection path

Switch threshold


Optical Digital Network Approach

The philosophy of ODN is based on O-E-O conversion whenever it is possible.

OTN manipulate analogical wavelengths;

ODN manipulate digital “bits”.


Network Layers: OTN vs ODN

OTM0PhysicalSection(OPSO)

Optical Transmission Section (OTS)

Band Multiplex Section (BMS)

Optical Digital Channel (ODCh)

Optical Channel Transport Unit (OTU)

Optical Channel Data Unit (ODU)

Optical Channel Payload Unit (OPU)

IP ATM Ethernet STM-N

Dig

ital

Anal

og

OTM0(not colored,

no OSC)

Optical Transport Module (OTM-n, n>1)

OTM0PhysicalSection(OPSO)

Optical Transmission Section(OTS)

Optical Multiplex Section (OMS)

Optical Channel (OCh)

Optical Channel Transport Unit (OTU)

Optical Channel Data Unit (ODU)

Optical Channel Payload Unit (OPU)

IP ATM Ethernet STM-N

Dig

ital

Anal

og

OTM0(not colored,

no OSC)

Optical Transport Module (OTM-n, n>1)

OTN ODN


ODN advantages

Each OADM site implements 3R regeneration:

the signal is cleaned up from noise and others distortion;It becomes possible to implement higher number of Channels -160 (C band, spacing 25 GHz);

The network lose transparency.


ODADM Description

MBM

Wes

t Li

ne

O-EO-EO-EO-E O-E O-E O-E

FECDigital W.

DSP

Matrix

To interface modules

MBM

Eas

t Li

ne

O-EO-E

O-EO-EO-EO-E

O-E

FECDigital W.

DSP

Matrix

To interface modules

Specific Interface Module

Electrical connection

Optical connection

Optical S

pliterO

ptica

l Split

erOptical pass-through


RECONCILATION BETWEEN THEAPPROACHES

To integrate different approach the existing OTN network must support Alien Wavelets (ITU-T G.698.2)

IPoDWDM is easy to integrate into OTN; IPoDWDM is easy to integrate into ODN but not efficiently;ODN can be integrate into OTN using an optical band split filter.


Example of ODN-OTN integration

The majority of deployed DWDM networks are equipped with 100GHz lambda spacing while transponders have stability for 50GHz spacing.

Even frequencies

Odd frequencies

192 192.1192.2192.3

192.4192.5

192.6

100Ghz

192.05192.15

192.25192.35

192.45192.55

192.65192.75

West Line East Line

50G

hz-

100G

hz

Filter

50G

hz-

100G

hz

Filter

C-Band ODADM

C-Band ROADM

100Ghz

Capacity Evolution

10 Gb/s -> 40 Gb/s -> 100 Gb/s- CD increases and PMD appears;OTN and IPoDWDM: - the limit of 160 channels (L+C band)ODN: - due to E-O-E no dispersion problems.- granularity of PIC is inflexible parameter (today either 10 or 40 Gb/s based)

New capacities are being studied byIEEE 802.3ba

G.698.2 should standardize new interfaces


Conclusions

OTN, IPoDWDM, ODN approaches analyzed;IPoDWDM and ODN are seen as very promissing;Examples on integration of both technologies;Stimulus for further research and standardization activities;


Back up

The following slide are for back up


OTN Network Elements

OLT (Optical Line Terminal)OADM/ROADM (Optical Add Drop Multiplexer) also ReconfigurableOLA (Optical Line Amplifier)OXC (Optical Cross-Connect)

OTS OTS OTS OTS OTS

OMS OMS

Och (not terminated in OADM site)

Client (not terminated in OADM site)

OLT OADM OLTOLA OLA OLA


IPoDWDM Network Elements

OTS OTS OTS OTS OTS

OMS OMS

DWDM MUX/DMUX

Optical fibre

Optical Line Amplifier

Optical colored interface

Client-OCh-OTU-ODU-OPU (yellow & green lambda)

OCh - Optical ChannelOMS - Optical Multiplex SectionONE - Optical Network ElementOTS - Optical Transmission Section

OTU - Optical Channel Transport Unit ODU - Optical Channel Data Unit OPU - Optical Channel Payload Unit

G.698.2 “black-link”

IP RouterClient-OCh-OTU-ODU-OPU(red & blue lambda)

Client-OCh-OTU-ODU-OPU(red & blue lambda)


ODN Network ElementsClient

MBM (Multiplexing Band Module)

Electrical connection

OLA (Optical Line Amplifier)

Optical connection

OTS OTS OTS OTS OTS

BMS BMS

ODCh ODCh

ODCh - Optical Channel

OTS - Optical Transmission Section BMS - Band Multiplex Section

DNE DNE DNE

DNE - Digital Network Element

OPUODU

OTU OTU

OTU - Optical Channel Transport Unit ODU - Optical Channel Data Unit OPU - Optical Channel Payload Unit

optical transport networks

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