3
Hyper Data Center Architecture Evolutions• Evolving from large mega data centers to inter-connected clusters of smaller
data centers within metro (<80Km)
• Closer to customers/End users
• Improved user experience
• Lower latency for mission critical app..
• Real estate, power cost/Op. flexibility
• Diversity for improved fault tolerance/disaster recovery
4
Connectivity Requirements for Hyper Data Centers
Data Centers Interconnects (DCI) within Metro
• Reach: 70-80km
• Connection bandwidth: >4Tbps
• 100G DWDM 400G DWDM
Intra-Data Center
• Reach~300m to 2Km
• Connection bandwidth
• Server: 25G/50G 100G
• Switches: 100G 400G
5
Servers
ToR Switches
LEAF Switches
SPINE Switches
Core Switches/Routers
Current 100G DC Optical Solutions
5
“DR” Optics
• 100G PSM4
SR Optics
Active Optical Cable (AOC)
100G
Direct Attached Cable (DAC)
Or Active Optical Cable (AOC)
25G or 2x25G
“FR” Optics
• 100G CWDM4
LR Optics
• 100G LR4
Acronym Reach Fiber
SR <100m MMF
DR <500m SMF
FR <2Km SMF
LR <10km SMF
6
6
Modulation Transition from NRZ to PAM4
• Current 100G solution based on 4x 25G NRZ Modulations
• Complex, and relative higher cost
100G PSM4
4x25G NRZ
100G CWDM4
4x25G NRZ
• To reduce cost and set foundation for efficient 400G
solutions, industry is driving adopting 100G with single
optical channel 50GB PAM4 modulation:
• 2x of Baud Rate
• 4 level modulation
7
• Total 22 Companies
• Defines 100G FR, LR and 400G FR4, LR4 with 50GB-PAM4
• Eliminate inverse gearbox with SERDES progression
• Lay foundation for improved 400G, and higher speed
• Strong Benefits:
• Much reduced optics elements leads to lower cost
(4x2.5G)
(1x10G)
Historical 10G Deployments
8
100G Optical Solutions Evolution
100G PSM4
4x25G NRZ500m
SMF
100G SR4
4x25G NRZ100m
MMF
100G LR4
4x25G NRZ10km
SMF
100G CWDM4
4x25G NRZ2km
SMF
100G DR
56GB-PAM4
100G FR
56GB-PAM4
100G LR
56GB-PAM4
9
Servers
ToR Switches
LEAF Switches
SPINE Switches
Core Switches/Routers
New 100G DC Optical Solutions
“DR” Optics
• 100G DR
SR Optics
Active Optical Cable (AOC)
100G
Direct Attached Cable (DAC)
Or Active Optical Cable (AOC)
25G or 2x25G
“FR” Optics
• 100G FR
LR Optics
• 100G LR
Acronym Reach Fiber
SR <100m MMF
DR <500m SMF
FR <2Km SMF
LR <10km SMF
10
Servers
ToR Switches
LEAF Switches
SPINE Switches
Core Switches/Routers
Transition from 100G to 400G
“DR” Optics
100G 400G
SR Optics
Active Optical Cable (AOC)
100G 400G
Direct Attached Cable (DAC)
Or Active Optical Cable (AOC)
25G/2x25G 50G/100G
“FR” Optics
100G 400G
LR Optics
100G 400G
11
400G Optical Solutions Evolutions
400G LR4
50GB-PAM4
100G SR16
16x25G NRZ
100m
MMF
400G DR4
4x50GB-PAM4500m
SMF
400G SR8
25GB-PAM4
400G SR4.2
25GB-PAM4
400G FR8
8x25GB PAM42km
SMF
LWDM400G LR8
8x25GB PAM410km
SMF
LWDM
400G FR4
50GB-PAM4
CWDM
12
Servers
ToR Switches
LEAF Switches
SPINE Switches
Core Switches/Routers
400G DC Optical Solutions
400G DR4 or
SR Optics
Active Optical Cable (AOC)
400G SR8
Direct Attached Cable (DAC)
Or Active Optical Cable (AOC)
50G/100G
400G FR4
400G LR4
Acronym Reach Fiber
SR <100m MMF
DR <500m SMF
FR <2Km SMF
LR <10km SMF
13
100G/400G DWDM DCI Solutions
2x25GB PAM4 QSFP28 1x50GB PAM4 QSFP28
Direct Detect
4x25G NRZ+MLSE
/or ODB CFP
400G
DP 16QAM
DCO
QSFP-DD, OSFP, COBO
TL
Coherent Detection
TL
100G
DP QPSK
ACO/DCO CFP2
14
Direct Detection Coherent Detection
Modulation format NRZ, ODB, PAM4 DP QPSK, DP 16QAM
Distance Reach 100G up to 80km with DCM 100G up to 2000km
400G up to 600km
Power Dissipation Low power, ~4W @ 16nm
DSP
High power, >15W @ 16nm
DSP
Size/Density Small. 100G fit QSFP28 Large size, 100G CFP2
Cost Low. 200-300% higher cost
Direct use in DC
switch
Yes Need special dedicated
switch or transponders
Best use case DC campus, metro-edg DCI Metro core DCI, Long Haul
Direct Detection Coherent Detection
Modulation format NRZ, ODB, PAM4 DP QPSK, DP 16QAM
Distance Reach 100G up to 80km with DCM 100G up to 2000km
400G up to 600km
Power Dissipation Low power, ~4W @ 16nm
DSP
High power, >15W @ 16nm
DSP
Size/Density Small. 100G fit QSFP28 Large size, 100G CFP2
Cost Low. 200-300% higher cost
Direct use in
Layer2/3 switches
Yes Need special dedicated
switches or transponders
Direct Detection Coherent Detection
Modulation format NRZ, ODB, PAM4 DP QPSK, DP 16QAM
Distance Reach 100G up to 80km with DCM 100G up to 2000km
400G up to 600km
Power Dissipation Low power, ~4W @ 16nm
DSP
High power, >15W @ 16nm
DSP
Size/Density Small. 100G fit QSFP28 Large size, 100G CFP2
Cost Low. 3-4x higher cost
Direct Detection Coherent Detection
Modulation format NRZ, ODB, PAM4 DP QPSK, DP 16QAM
Distance Reach 100G up to 80km with DCM 100G up to 2000km
400G up to 600km
Power Dissipation Low power, ~4W @ 16nm
DSP
High power, >15W @ 16nm
DSP
Size/Density Small form factor QSFP28 Larger size, 100G CFP2
Direct Detection Coherent Detection
Modulation format NRZ, ODB, PAM4 DP QPSK, DP 16QAM
Distance Reach 100G up to 80km with DCM 100G up to 2000km
400G up to 600km
Power Dissipation 100G PAM4 Low power,
~4W @ 16nm DSP
High power, 100G ~15W @
16nm DSP;
Direct Detection Coherent Detection
Modulation format NRZ, ODB, PAM4 DP QPSK, DP 16QAM
Distance Reach up to 80km with DCM 100G/400G >80Km without
DCM
50GB PAM4 vs. Coherent Optical Solutions
Direct Detection Coherent Detection
Modulation format 50GB PAM4 DP QPSK, DP 16QAM
15
Pluggable Form Factors Supporting 400G Solutions
QSFP DD MSA:
• Backward compatible with QSFP-28
• Support 8x56G PAM4 Electrical Interface
• Allow 36x400G=14.4T for 1RU switch density
• Up to 12W power dissipation
CFP8 MSA:
• First Gen. 400G Router interface
• Unlikely for large scale data center Deployment
OSFP MSA:
• Support 8x56G PAM4 Electrical Interface
• Allow 32x400G=12.8T for 1RU switch density
• Up to 15W Power dissipation
Consortium for On-board Optics:
• Support up to 16x56G PAM4 Electrical interface
• Up to 17.5W, potentially
16
Summary
• 100G data center optical solution transitioning from 4x25G to 1x100G with
56GB PAM4 technology
• Lower cost and future proof
• Efficient 400G solution emerging based on 4x56GB PAM4
• Good industry support with 100G Lambda MSA
• 56GB PAM4 DWDM as complementary DCI solution vs coherent
• A few plugable form factors emerging to support 400G
• QSFP-DD most promising for widest range of deployments