Huawei-10G to 40G to 100G DWDM Networks

The Road from 10G to 40G to 100G DWDM Networks www.huawei.com

Christopher Skarica Chief Technology Officer North American MSO and Cable Ottawa, Ontario

AGENDA 

 



 

WDM Introduction  Optical Layer Convergence  Dense and Coarse WDM  DWDM System Building Blocks  DWDM Optical Line Design Considerations Current DWDM Networks and Service Drivers 40G Overview  40G Facts  40G System Design Considerations  40G Deployment Challenges 100G Status  100G Standards Bodies Work and Review (IEEE, ITU, OIF)  100G System Design Considerations  100G Deployment Challenges 40G/100G Components Maturity Review Conclusions

Page 2

Definition of WDM

W

D

Wavelengt h Division

M Multiplexi ng

A technology that puts data from different optical sources together, on a single optical fiber, with each signal carried on it’s own separate light wavelength or optical channel

Page 3

Easy Integration of WDM Technology with Existing Optical Transport Equipment WDM Fiber Mux λ 1

Independent Optical Bit Rates and Formats

λ 2

SONET

ATM

λ 3 Gigabit Ethernet Fibre Channel λ 4 Single Optical Fiber

WDM systems integrate easily with existing optical transport equipment and enable access to the untapped capacity of the embedded fiber. They also eliminate the costs associated with mapping common data protocols into traditional networking payloads. Page 4

Convergence at the Optical Layer Traditional Approach

Wavelength Networking D1 Video

Video Video

Gigabit Ethernet

DWDM Optical Network

Commercial Commercial Services Services IP IP SONET SONET

•Special Assemblies •Network Overlays

FICON

Async

ESCON SONET OC-1/3/12/48

Fibre Channel

•Ubiquitous Networking •Forecast Tolerant

One Network = Rapid Services Turn-up & Reduced Operations Costs Page 5

DWDM and CWDM Technology Definitions DWDM – Dense WDM Technology for amplified, high bandwidth applications. Ideal for Metro Core, Regional, and Long Haul applications. Squeezes as many channels as possible into optical spectrum supported by today’s optical amplifier technology. Characterized by a tight channel spacing over a narrow wavelength spectrum, typically 50 – 200 GHz (I.e. ∼ 0.4nm – 1.6nm) spacing in the C and L Bands

O - Band

λ (nm)1280

E - Band

1320

1360

S - Band 1440

1400

1480

C-Band 1520

L - Band

1560

1310 nm

1600

1640 λ (nm)

DWDM WINDOW

CWDM – Coarse WDM Technology for un-amplified, lower channel count applications. Less cost

O - Band

λ (nm)1280

1320

E - Band 1360

1400

S - Band 1440

1480

C-Band 1520

1560

CWDM WINDOW Page 6

1610

1590

1570

1550

1530

1510

1490

1470

1450

1430

1410

1390

1370

1350

1330

1310

1290

1270

than DWDM. Ideal for Metro Access applications. Characterized by a wide channel spacing over a wide optical spectrum – 20 nm spacing from 1270 – 1610 nm

L - Band 1600

1640 λ (nm)

EDFA Gain Spectrum O - Band

λ (nm)1280

1320

E - Band 1360

1400

S - Band 1440

1480

C-Band 1520

1310 nm

1560

Operates in 3rd low-loss window of optical fiber near 1.5µ m Broad operating range of >30nm



Amplification across multiple wavelengths

Available for both C-Band and L-Band



High optical gain of 20dB to 30dB



All-optical amplification





1600

DWDM WINDOW





L - Band

Bit-rate insensitive (OC-12, OC-48, OC-192 and beyond)

Page 7

1640 λ (nm)

Dense WDM Wavelength Plan – ITU-T G.694.1

ITU-T G.694.1 Standard DWDM Channel Assignments 200 GHz spacing = 20 Channels in C Band 100 GHz spacing = 40 Channels in C Band 50 GHz spacing = 80 Channels in C Band 25 GHz spacing = 160 Channels in C Band

Standard ITU Grid allows lasers and filters to be built to a common specification Page 8

Optical Network Building Blocks Terminal

Terminal

Line

λ Translator for Pt. to Pt. connectivity

λ Translator for Pt. to Pt. connectivity

L2/L3 Switch or SONET Cross Connect

L2/L3 Switch or SONET Cross Connect

L2/L3 Switch or SONET Cross Connect

Line – a DWDM fiber optic system with Optical Amplifiers, dispersion compensation, and optical couplers providing high capacity, pt. to pt., ring, or mesh based connectivity between end points 100’s or 1000’s of km apart Terminal – wavelength translators/combiners for conversion of client optical signals to 1550 nm, DWDM compliant wavelengths AND/OR SONET and L2/L3 switches providing client signal aggregation and presentation of 1550nm, DWDM compliant wavelengths. Page 9

DWDM Building Blocks Software Control ROADM Channel Filter Transponders

λ

Group Filter

1



Lambda Granularity



Optical Branching



Remote Reconfiguration

SONET

…

…

Routers

Amp Product ‘x’

λ

n



Channel Filters 200Ghz, 100Ghz, 50Ghz, or 25GHz spacing

Amplifiers 

Low Noise



Variable Gain/Flexible Link Budgets Page 10

Optical Line Design Considerations 

Optical Signal to Noise Ratio performance 

Dictated by amplifier gain and spacing, no. of channels of system, and OSNR tolerance of DWDM receiver





Chromatic and Polarization Mode Dispersion of fiber 

Different for different bit rate signals



Causes Pulse spreading over distance



More critical for 10Gbps and higher bit rate signals

Non Linear effects that disturb the energy and shape of a signal 

Caused by high optical power levels, small fiber core diameter, and dispersion characteristic of fiber

Page 11

DWDM Optical Line Systems Today 

The majority of deployed terrestrial DWDM optical line systems have been designed for 40/80 channels (100/50GHz spacing) of 10Gbps signals



Amplifier spacing and OSNR performance, dispersion compensation, and NLE avoidance is optimized for 10 Gbps signals in the majority of today’s networks



SO, Why the talk of 40G and 100G and how do we accommodate for these higher rate signals without re-designing the embedded optical line systems ????

Page 12

MSO/Telco Optical Transport Trends National Network Long Haul Optical Networks being deployed/investigated Metro optical primary to reduce the no. of ring transport capacity Internet peering points upgrades and enable long underway….Metro • Network Operation Center distance VOIP transit DWDM Technology is • DWDM Technology • Call Processing Center winning the day Dominating

Regional Regional Headend Network

• Data Center • Internet Peering Point

• Methods of Access network Fiber expansion being investigated ~5km expanded Primary Hub business and residential Secondary Hubservice offerings

300-1200Km per span

Primary Network

DSL HFC PON

180 ~ 300km circumference

Secondary Network

Page 13

Evolving DWDM Transport Network dD igit

al B roa

IPTV

Sw itch e

dca

st

Over the Top Video

oO e Vid

Digital Digital DWDM DWDM Transport Transport Network Network

TV HD Wireless

M

W av elen gth S e

Co m m er

HSD

P SI

DVR Start Over/n

••Larger LargerCapacity Capacity

• •Flexible Flexible • •Hub Hub&&Mesh MeshTraffic TrafficFlows Flows • •High HighReliability Reliability • •Efficient Efficient

ia d e tl im u

nd a em D n

ci al

Da t

Page 14

a

Se rv

ic e

rvice

s

s

40G Here Today 

Commercially deployed and available 40G technology is now standardized in the SDH (STM-256), SONET (OC-768), and OTN (OTU-3) worlds



40G has become commercially deployed (starting in 2007) to increase fiber capacity – many large operators (eg. Verizon, AT&T, Comcast) are running out of wavelengths on existing 10G DWDM line systems



40G DWDM interfaces are about 7-8 X that of a 10G and 10G has been dropping in price more rapidly than 40G



BUT, let’s not confuse this with 40 Gigabit Ethernet which is being ratified and is not an approved standard today !!! (we’ll talk about that shortly)

Page 15

40G Facts 





 

Thus far, the largest 40G application has been router-router interconnects (using PoS) with the largest commercial deployments having been Comcast and AT&T Global revenue for 40G line cards in 2007 was $178M – expected to grow 48 percent annually through 2013 and reach almost $2B annually (Ovum) 40 G services expected to grow at a compound annual rate of 59% from 20072011 (Infonetics) 40 G is here to stay and will grow dramatically over the coming years How do we accommodate for these higher rate 40G signals without re-designing the embedded optical line systems ? – By using advanced modulation techniques (amplitude and phase – not just 1+0’s, on and off anymore) to gain spectral efficiencies, coherent receiving, as well as advanced dispersion compensation techniques to make the 40G signal “look” like a 10G signal

Page 16

40G Transmission Platform 1*40G SDH/SONET 4*10G SDH/SONET 1*40G SDH/SONET

43Gb/s

43Gb/s 4x10Gb/s

 10G, 40G uniform platform  15*22dB @80*40G design rule

Router STM-256/OC-768

Router STM-256/OC-768

Page 17

40G is More Nonlinear Sensitive than 10G additional

Lower input power under given BER

Chirp introduction Reduce Nonlinearity impairment

RZ format

Differential phase instead of absolute phase

40G is 4 times the frequency of 10G, so inter-channel and intra-channel interferences bring a bigger problem.  Long distance transmission systems solve this problem by introducing additional laser chirp, RZ format, differential phase and lower input power 

Page 18

Technical Challenges from 10G 40G item

Challenges: 10G40G

Solutions

OSNR Required

6dB more

Advanced modulation formats

Filtering effect

4x more

Spectral-efficient modulation format (ODB, xRZ-DQPSK for WDM@50GHz)

CD tolerance

1/16

TODC (per channel compensation)

Nonlinear effects

More sensitive to iFWM & iXPM

Nonlinear-resilient RZ format ,chirp

1/4

Multi-level (/multi-carrier) modulation

PMD Tolerance

processing

(DQPSK for reduced symbol rate and better optical spectrum utilization)

Advanced Optical Modulation formats and Adaptive per Channel Dispersion Compensation are at the heart of solutions. Page 19

40Gbit/s Modulation summary

40G Formats Channel Space

Nonlinear

Max possible OSNR Sensitivity PMD Tolerance

Tolerance

Launch Power (15 spans)

ODB

50GHz

Good

Ref.

Ref.

Ref.

CS-RZ

100GHz

Very Good

+3dB

+0.5dB

1.5x

NRZ-DPSK

100GHz

Good

+3dB

+3dB

1.4x

PDM-QPSK

50GHz

Poor

-4dB

+3dB

>6x (6x is 10G’s PMD tolerance)

DQPSK

50GHz

Good

+1dB

+3dB

4x

Fragmented components supply chain reducing 40G cost reduction ability Page 20

Adaptive Dispersion Compensation 

Uneven residual dispersion due to unmatched dispersion slopes of DCM and fiber may exceed the dispersion tolerance of a 40G DWDM system



ADC (Adaptive Dispersion Compensation) allows DWDM systems to compensate dispersion on per channel basis, and therefore optimize the receiving performance for native 40G over 10G optical line systems 3000 annel gth Ch avelen W r e g Lon

Accumulated Dispersion (ps/nm)

2000 1000 0

-1000

Short W avelen gth Ch a

-2000 -3000

0

240

nnel

480

720

Distance (km)

Same receiving performance in 400ps/nm tolerance Page 21

Terminal's Dispersion Equalization

960

1200

Native 40G over 10G Optimized Optical Line System 10 G Optimized Optical Line System VOA

2.5G OTU

2.5G OTU DCM

DCM

DCM

10G OTU

DCM

10G OTU

OADM

ADC

40G OTU

40G OTU

40G transceiver unit (OTU)

40G OTU

OTM 

ADC

ADC

OADM

OTM

40G wavelength directly over the existing optimized 10G optical line system ：     

Advanced coding format allows for existing 10G MUX/DMUX Built-in VOA and ADC allows for perfect match with 10G in power level and dispersion High sensitivity receiver (similar power level and OSNR tolerance as for 10G) Same EDFA Transparent transport of client signal  

4*10G(OC-192/STM-64) 1*40G(OC-768/STM-256, 10GE WAN/LAN)

Page 22

40G OTU

40G/100G Quick Overview 

The push for 40G and 100G involves BOTH Routing and Transport systems



Why the quick jump to 100G from 40G ? – Network traffic growth, router efficiencies and a standards body (IEEE) that decided to work on both 40GbE and 100 GbE at the same time thereby aligning the timetables for both



Is this about Cable, Telco’s – or both ? – Both – mostly driven in North America by Comcast, AT&T, and Verizon



What’s the hype factor – Higher for 100G than 40G



The 40G and 100G buzz is coming from both service providers and vendors

Page 23

100G Standards Forums 

IEEE 802.3(40/100GE Interface) 

Has approved 40G/100G Ethernet Draft Standard-- IEEE802.3ba (In Dec. 2007)



Final Ratification Expected in mid 2010



100GE expected to be applied in core networking (Router) and 40GE expected to be applied in servers and computing networking (LAN Switches)



Two kinds of 100GE PHY optical client interface were selected: i) 4x25G CWDM for SMF; ii) 10x10G Parallel module for MMF







Provide appropriate support for OTN framing (100GE to ODU-4)

ITU-T SG15(100G OTN Mapping/Framing) 

Proposal for ODU4 Framing



It has been accepted in G.709 in Dec.2008; the rate of OTU-4 is 111.809973 Gb/s



Proposal for 100GE mapping to ODU4 frame: It is under discussion



Proposal for OTN evolution: It is under discussion

OIF PLL(100G LH Transmission – components/DSP) 

This project will specify a 100G DWDM transmission implementation agreement to include:



i) Propagation performance objective



ii) Modulation format : Optimized DP-QPSK with a coherent receiver – OFDM also being considered



iii) Baseline Forward Error Correction (FEC) algorithm



iv) Integrated photonics transmitter/receiver Page 24

100G – A Developing Standard We Are Here 2007 J

F

M

A M

IEEE802.3 100GE Standard

J

J

2008 A

S O N

IEEE 802.3ba 40GE/100GE PAR Approved

D

J

F

M

A M

J

J

2009 A

S O N

IEEE 802.3ba D1.0 TF Draft

D

J

F

M

A M

J

J

2010 A

S O N

D

IEEE 802.3ba D3.0 LMSC Ballot

IEEE 802.3ba D2.0 802.3WG Ballot

J

F

M

A M

J

J

A

IEEE 802.3ba 40GE/100GE Standard

ITU-T Q11/SG15 OTN Standard G.709 Amd3 Consent OTU4 Definition

ODU4 Proposal

OIF PLL 100G LH Transmission

100G Project Kick off

IA Draft

G.709 New Version Consent

IA to Straw Ballot

ITU-T SG15 OTU-4 standard

Project Complete

IA to Principal Ballot

Page 25

S O N

D

From 40G to 100G: Additional Challenges Challenges

10G  40G

40G 100G

OSNR Required

6dB more

~4dB more

CD tolerance

1/16 (4km vs 65km SSMF for NRZ)