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: 10G40G
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)
<1/6 (<1km vs. 4km in SSMF, NRZ) (2.5km vs. 15km in SSMF, RZ-DQPSK)
Nonlinear effects
PMD Tolerance
iFWM & iXPM (dominant on SSMF) XPM (esp. with coexisting 10G OOKs) 1/4 (2.5ps vs 10ps for NRZ)
Key to economical scaling of 100GE:
Intrachannel effect severer limiting Launch Power (Bit separation 2.5x smaller)
1 / 2.5 (max DGD tolerance: 8ps vs 21ps, RZ-DQPSK)
Innovative way to deal with PMD, NLE & OSNR deficits Page 26
40G&100G Components Maturity Analysis 40G
100G
100G Commercial Time
Laser
OK
OK
OK
Driver
OK
Small supplies’ Sample
2009
Modulator
OK
Small supplies’ Sample
2009
Framer
OK
Small supplies’ Sample
2010
FEC
OK
Small supplies’ Sample
2010
MUX/DeMUX
OK
OK
OK
Receiver
OK
Small supplies’ Sample
2009
40G components supply chain is mature enough to support commercial deployment levels now.
100G components supply chain not mature yet – first samples 2009/2010 ; expected to ramp in volume in 2011 after all standards ratified
Page 27
100GE Facts
Existing solutions today are proprietary in nature and cost prohibitive (more than 10x the cost of a 10G)
DP-QPSK modulation expected to win the day at the OIF although OFDM is gaining its fans – the goal is to have a consolidated components supply chain and ecosystem to better drive cost reduction through manufacturing volume
Primarily being driven to achieve further router-router efficiencies
A single 100G router interface is much more efficient than 10x10G interfaces that use link aggregation (only about 60% efficient and requires complex routing algorithms to load balance across 10 interfaces)
A large push in North America by Comcast, Verizon, and AT&T who are trialing proprietary 100G solutions today
Will not be standardized and shipping in quantity until late 2010/early 2011
Page 28
Conclusions
10G still clearly provides the lowest cost per bit transported
Operators can choose to continue to deploy 10G although 40G is available today to relieve fiber exhaustion on existing DWDM systems
40G (SONET/SDH/OTN) can be run native on today’s optimized 10G optical line systems
40GE/100GE will not be fully standardized and commercially available until late 2010/early 2011
Once standardized, 100GE is anticipated to be cost effective out of the gate due to extensive standards work and cross industry collaboration
Page 29
THANK YOU VERY MUCH !!!! Questions
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