OFC 2019 - 100G DWDM DCI/Metro Network Solutions - Debating alternatives to Coherent

LINE SIDE 100 Gb/s DWDM
NETWORK SOLUTIONS –
DEBATING THE OPTIONS
Moderators
Larry Johnson – Founder- FiberStory
Tim Yount – Co-founder- Fiber Insight
Richard Ednay – Technical Dir - Optical Technology Training
OFC 2019 – San Diego, CA
www.fiber-story.com
www.fiberinsight.com
www.ott.co.uk

Introduction to session
Introduction of panelists
Introduction to each panelist
Individual topic presentations
Question/answer period at end of
session
© July 2018

MARK FILER - MICROSOFT
PRINCIPAL OPTICAL NETWORK ARCHITECT
GERT SARLET - FINISAR
PRODUCT LINE MANAGER
RADHA NAGARAJAN – INPHI
CTO – OPTICAL INTERCONNECTS
© July 2018

MUHAMMED SARWAR – FUJITSU NETWORK COMMUNICATIONS
GLOBAL PRODUCT PLANNER
JOERG-PETER ELBERS – ADVA
SR VP - ADVANCED TECHNOLOGY, STANDARDS & IPR4
JOHN D’AMBROSIA – IEEE
802.3 WORKING GROUP CHAIR (ETHERNET EVANGELIST)
© July 2018

100 Gb/s DWDM (line side) Networks
< ~80km >
“Coherent-based”
100Gb/s Dual Polarization Multiplexed QPSK Modulation
Coherent Detection/advanced signal processing
“Direct Detection-based”
PAM-4 (Pulse Amplitude Modulation)
Direct Detection

Mark Filer
Principal Optical Network Architect, Azure Networking

Region
Azure WAN
Backbone
Microsoft regional architecture
long haul
DCI
AZ set 2AZ set 1

Microsoft regional fiber statistics

A solution tailor-made for DCI
Inphi ColorZ PAM4
4 Tb/s44444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444444 TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////sssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss

DCI PAM4 performance
FEClimit
-

© Finisar Corporation Confidential 13
March 7, 2019
Line Side 100Gb/s DWDM Network Solutions –
The Finisar Perspective

100G DWDM Coherent vs Direct Detect
100G ”ZR” Coherent 100G DWDM Direct Detect
Modulation format 1 × 28Gbaud DP-DQPSK 2 × 56Gb/s (28Gbaud) PAM4
Grid spacing 50GHz 100GHz
Loss budget > 23dB
• Supports single channel unamplified
point-to-point links up to 80km
• Supports DWDM unamplified point-to-
point links up to 40km
Negative
• Tx output power < Rx sensitivity
• Needs EDFA to close link back-to-back
Chromatic dispersion
tolerance
2400 ps/nm
• Compensation of CD and other link
impairments in DSP
+/-100ps/nm
• Requires tunable CD compensation
module in link
OSNR tolerance 16dB/0.1nm
• Very relaxed OSNR requirements
• Allows for single amplifier stage for
DWDM point-to-point links up to 80km
31dB/0.1nm
• Link losses, EDFA gain and noise figure
need to be carefully managed to ensure
sufficient OSNR (and input power) at Rx

100G Direct Detect – Application Examples
Link losses, EDFA gain and noise figure need to be carefully managed to
ensure sufficient OSNR and input power at Rx
Tunable dispersion compensation module required
Loss/gain 2dB 5dB 20dB (80km×0.25dB/km) 6dB 5dB 2dB
Tx
Tx
Rx
Rx
…
DWDM amplified point-to-point links up to 80km
DCM
Use cases:
• Data center interconnect

100G ”ZR” Coherent – Application Examples
Significantly relaxed link loss and EDFA specifications due to improved
sensitivity and OSNR tolerance of receiver
No need for chromatic dispersion compensation in the optical link (managed
by DSP in the transceiver)
Loss/gain 2dB 5dB 20dB (80km×0.25dB/km) 5dB 2dB
Tx
Tx
Rx
Rx
…
Use cases:
• Data center interconnect
• Mobile backhaul
• Cable MSO remote PHY

Hub
Single amplifier stage in hub node
Booster amplifier for downstream traffic
Pre-amplifier for upstream traffic
Rx
Rx
Tx
Tx
…
Loss/gain 2dB 5dB 20dB (80km×0.25dB/km) 5dB 2dB
Tx
Tx
Rx
Rx
…
Use cases:
• Mobile backhaul

Tx Rx
Loss 1dB 20dB (80km×0.25dB/km) 1dB
Single channel unamplified point-to-point links up to 80km
Tx
Tx
Tx
Rx
Rx
Rx
…
Loss 1dB 5dB 10dB (40km×0.25dB/km) 5dB 1dB
DWDM unamplified point-to-point links up to 40km
Use cases:
• Mobile backhaul

100G DWDM Coherent vs Direct Detect
100G ”ZR” Coherent 100G DWDM Direct Detect
Modulation format 1 × 28Gbaud DP-DQPSK 2 × 56Gb/s (28Gbaud) PAM4
Grid spacing 50GHz 100GHz
Loss budget > 23dB
• Supports single channel unamplified
point-to-point links up to 80km
• Supports DWDM unamplified point-to-
point links up to 40km
Negative
• Tx output power < Rx sensitivity
• Needs EDFA to close link back-to-back
Chromatic dispersion
tolerance
2400 ps/nm
• Compensation of CD and other link
impairments in DSP
+/-100ps/nm
• Requires tunable CD compensation
module in link
OSNR tolerance 16dB/0.1nm
• Very relaxed OSNR requirements
• Allows for single amplifier stage for
DWDM point-to-point links up to 80km
31dB/0.1nm
• Link losses, EDFA gain and noise figure
need to be carefully managed to ensure
sufficient OSNR (and input power) at Rx
Applications • Can be used on same links as current 10G
Tunable SFP+/XFP
• Data center interconnect (DCI), mobile
backhaul, cable MSO remote PHY, …
• Limited to DCI applications with highly
engineered links
Cost • Wider application space and therefore
higher volumes will drive down cost
• Limited application space, limited supply
base will keep costs higher

Thank you

21Radhakrishnan Nagarajan, “Datacenter Interconnects”, OFC 2019, copyright © Inphi Corporation
100G, PAM4 based between Datacenter, DWDM Interconnects
Line Side 100Gb/s DWDM Network Solutions – Debating the Options
Radhakrishnan Nagarajan
March 7, 2019

Technology choices in DCI
Distance (km)
IEEE 802.3
PSM4, LR4
CWDM4
100G
CWDM
PAM4 (100G, DD)
Coherent
100G/200G/400G/600G
DWDM
Coherent
QPSK/8QAM/16QAM
100G/200G/400G
DWDM
Coherent
QPSK/8QAM
100G/200G/300G
DWDM
0.1 2.0 10 100 600 10000
Inside DC DCI-Edge DCI-Metro DCI-Long Haul
Distance (km)
IEEE 802.3
PSM4, LR4
CWDM4
100G
CWDM
Coherent
QPSK/8QAM/16QAM
100G/200G/400G Pluggable DCO
DWDM
0.1 2.0 10 100 600 10000
Inside DC DCI-Any Distance
100G, PAM4, DD
400G, ZR, Coherent
“Traditional” DCI
< 120km
Coherent
400G/16QAM, ZR
Pluggable DCO

First 100G PAM4 DWDM QSFP-28 module
• Compatible with the QSFP28 MSA as in SFF-8665
• Standard CAUI4 electrical interface
• Typical power consumption ~ 4.5W
• Electrical Input: 4 x 25.78125 Gbit/s NRZ
• Optical Output: 2 x 28.125 Gbaud PAM4

Microsoft regional optics, developed at Inphi
Mark Russinovich, CTO, Microsoft Azure, Microsoft Ignite 2017

3.6Tbit/s, 1 RU Switch Capacity
Coherent vs. PAM 4 module for 100G DCI
CFP2, 100G DCO
~15 to 20W
QSFP-28, 100G ColorZ
~4.5W
< 30% Power
< 20% Space
Arista Jericho Switch
QSFP-28
ColorZ Modules

80km, switch to switch up to 4Tbit/s interconnect
Arista Switch ADVA Line System
36 Port Switch

Thank you

Fujitsu Proprietary and Confidential All Rights Reserved, ©2018 Fujitsu Network Communications
Muhammad Sarwar
Fujitsu Network Communications Inc.
100G over 80km DCI Options
28

100G 80km – PAM4 vs. Coherent
2
PAM4 Coherent
Applications Up to 80km Flexible & Scalable
Technology Limited Evolutionary
IPoDWM Yes Yes
Security No Yes
CAPEX Low Catching up!!

30

Jörg-Peter Elbers
OFC Panel: Line Side 100Gb/s DWDM Network Solutions – Debating the Options
for the data center interconnect?
Coherent or direct-detect

32
Data centers require high-capacity interconnects
DC
Spine
switch
DWDM
Transponder
DC
Edge
router
Core OLS
Customer
Traffic
DCI OLS
It is good to have a choice – open line system & best-of-breed terminal optics
Ring or mesh
100s-1000s of km
Fiber scarce
Point-to-point
<80km distance
Can be fiber rich
Core connectivity
DCI connectivity

33
• High performance and spectral efficiency
• On-board and CFP(2) form factors
• 100Gbit/s to 600Gbit/s available today
• DSP-based dispersion compensation
• “Good enough” for P2P DCI applications
• The only solution in QSFP28 form factor
• 100Gb/s available today
• Needs optical dispersion compensation
Direct detectCoherent
How to manage dispersion for direct detect?
DWDM line-side options for DCI applications
DWDM
QSFP28CFP2-DCO
DWDM terminal with
on-board optics

34
Smart amplifier offers coherent-like automation for direct-detect optics
Operational simplicity for direct detect
• Automatic dispersion measurement
• Automatic dispersion compensation
• Automatic gain, tilt, and power setting
• Optional integrated OTDR
• Optional optical channel monitor
Smart features
+ =
Configuration
Provisioning
Monitoring
Alarms
TACACS+
Radius
CLI
REST
NETCONF
WebGUI
Zero Touch Prov
SNMPv2c
REST
NETCONF
Streaming Telemetry
FCAPS Control
REST

35
Highest capacity, functionality and flexibility with DWDM terminal –
Lowest rack space with DWDM QSFP28 in switch/router
Which line side option to pick? – It depends…
38.4
19.2
9.6
4.8
0
5
10
15
20
25
30
35
40
45
600G Coh. 200G Coh. 100G Coh. 100G PAM4
C-bandcapacity(Tb/s)
Modulation format
CFP2-DCO
DWDM
QSFP28
DWDM terminal with
on-board optics

36
The good news? – An open DCI line system supports all!
Open APIs
Pre-amp
Pre-ampBooster
Booster
WDM filter
Open APIs
WDM filter
Switch/router
with PAM4 QSFP28
Coherent interfaces
Switch/router
with PAM4 QSFP28
Coherent interfaces
Disaggregated
terminal equipment
Disaggregated
terminal equipment

Thank you
IMPORTANT NOTICE
The content of this presentation is strictly confidential. ADVA Optical Networking is the exclusive owner or licensee of the content, material, and information in this presentation.
Any reproduction, publication or reprint, in whole or in part, is strictly prohibited.
The information in this presentation may not be accurate, complete or up to date, and is provided without warranties or representations of any kind, either express or implied. ADVA
Optical Networking shall not be responsible for and disclaims any liability for any loss or damages, including without limitation, direct, indirect, incidental, consequential and special
damages, alleged to have been caused by or in connection with using and/or relying on the information contained in this presentation.
Copyright © for the entire content of this presentation: ADVA Optical Networking.
jelbers@advaoptical.com

HUAWEI TECHNOLOGIES CO., LTD.
Line Side 100Gb/s DWDM Network
Solutions – Debating the Options
Introducing IEEE P802.3ct
100 Gb/s and 400 Gb/s over DWDM Systems
John D’Ambrosia
March 7, 2019

Regarding the Views Expressed
My Industry Involvement
Acting Chair, IEEE P802.3ct, 100 GbE and 400GbE over DWDM Systems Task Force
Chair, IEEE P802.3cn 50 GbE, 200 GbE, 400GbE SMF Task Force
Chair, IEEE 802.3 New Ethernet Applications (NEA) Ad Hoc
Recording Secretary, IEEE 802 Executive Committee
Chairman, Ethernet Alliance Board of Directors
Senior Principal Engineer, IP Standards Team North America, Futurewei
The views being presented in this educational material on the respective IEEE 802.3
standards under consideration are the views of the author(s), and do NOT represent a
formal position or interpretation of the respective standard by The Ethernet
Alliance. This document is provided on an “AS IS,” “AS AVAILABLE,” and “WITH ALL
FAULTS” basis, with no representations or warranties whatsoever, whether express,
implied, statutory, at common law, or otherwise.
Per IEEE-SA Standards Board Bylaws, Dec 2016
“At lectures, symposia, seminars, or educational courses, an individual presenting
information on IEEE standards shall make it clear that his or her views should be
considered the personal views of that individual rather than the formal position of
IEEE. ”

Introducing IEEE P802.3ct
100 Gb/s and 400 Gb/s over DWDM Systems
Task Force Webpage - http://www.ieee802.org/3/ct/index.html
Key Application Drivers:
Cable MSO Distribution Networks
Mobil Backhaul Networks
Data Center Interconnect
Key Objectives (Full objectives - http://www.ieee802.org/3/ct/3ct_Objectives_190212.pdf)
For 100 Gb/s Ethernet - Provide a physical layer specification supporting 100 Gb/s
operation on a single wavelength capable of at least 80 km over a DWDM system.
For 400 Gb/s Ethernet - Provide a physical layer specification supporting 400 Gb/s
operation on a single wavelength capable of at least 80 km over a DWDM system.
Adopted Timeline Completion – Sept 2021

DWDM Link Types and Terminology
http://www.ieee802.org/3/B10K/public/18_01/anslow_b10k_01_0118.pdf
DWDM PHY:
DWDM Channel:
DWDM Link:
DWDM System:
DWDM PHY:
DWDM System:
Source:
http://www.ieee802.org/3/B10K/public/adhoc/18
_0227/nowell_b10k_01b_180227.pdf

Key Decisions to Date
100 GbE 400 GbE
Channel Model Straw poll support for ITU-T Black Link Approach
# of Channels No decision yet
Channel Spacing Straw poll support for 100 GHz
Modulation Format DP-DQPSK DP-16QAM
Frame Assumption GMP Mapping
ITU-T G.709 Clause 17.7.5
Based on OIF 400ZR
FEC “Staircase” (255, 239)
Hard Decision
ITU-T G.709.2 Annex A
CFEC
Tx Metric No decision yet

Project Schedule

Thank You!
John D’Ambrosia
Acting Chair, IEEE P802.3ct Task Force
Chairman, Ethernet Alliance
Senior Principal Engineer
IP Standards Team, Futurewei
Email – jdambrosia@ieee.org
Follow me @jodam on Twitter
Follow me on LinkedIn
Ethernet Alliance: visit www.ethernetalliance.org;
Follow @EthernetAllianc on Twitter
Join the Ethernet Alliance LinkedIn group
Visit the Ethernet Alliance Facebook page
IEEE P802.3cn 400GbE Task Force:
http://www.ieee802.org/3/cn/index.html

Q&A Session
1. Mark Filer - Microsoft
2. Gert Sarlet - Finisar
3. Radha Ragarajan - Inphi
4. Muhammed Sarwar - Fujitsu
5. Joerg-Peter Elbers - ADVA
6. John D’Ambrosia - IEEE

Discussion Summary
< ~80km >
“Coherent-based”
100Gb/s Dual Polarization Multiplexed QPSK Modulation
Coherent Detection/advanced signal processing
“Direct Detection-based”
PAM-4 (Pulse Amplitude Modulation)
Direct Detection
PAM-4 Alternative to Coherent-based 100G DWDM
Pros Cons
Driven by transceivers Limited reach
Lower cost Noise sensitivity
Smaller footprint Low noise amps needed
Lower power usage Precise CD compensation required
Less complex No current standard

Thank You!
Panelists
Attendees

OFC 2019 - 100G DWDM DCI/Metro Network Solutions - Debating alternatives to Coherent

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