Optics for 100G and beyond

Guylain Barlow
JDSU Network & Service Enablement
100G Client Interface Evolution

© 2014 JDS Uniphase Corporation | JDSU CONFIDENTIAL AND PROPRIETARY INFORMATION 2
 Market Evolution
• 100G Transceiver volumes
 High-Speed Client Interfaces
• Emerging Interface Types
• Optics form Factor Evolution
• Data Center Influence on Form Factors
 Validating high-speed optics
 Evolution to 400G
Agenda

100G Interface Evolution
Infonetics 10G/40G/100G
Optical Transceivers Oct. 2014
100G is now dominant in long-haul
LR4 most popular as a client telecom interface
Data Center though is a key growth area

High Speed Interface Types
Interfaces & Form Factors

Current 100GE Interface Types
Interface Reach Medium Parallelism Standard
100GBASE-ER4 40 km SMF 4 λ / dir 802.3ba
100GBASE-LR4 10 km SMF 4 λ / dir 802.3ba
10x10 MSA (LR10) 2 or 10 km SMF 10 λ / dir 10x10 MSA
100GBASE-SR10 100 m
125 m
OM3 MMF
OM4 MMF
10 fibers / dir 802.3ba
100GBASE-SR4 70 m
100 m
OM3 MMF
OM4 MMF
10 fibers / dir 802.3bm
100GBASE-CR10 7 m Twin-axial
electrical
10 cables / dir 802.3ba
100GBASE-CR4 4 m Twin-axial
electrical
10 cables / dir 802.3bm
IEEE 802.3ba
• Main applications:
• LR4: Most common interface in telecom by far
• Key missing need is for reaches between 100m and 10km  data center

100G Pluggables – Industry Roadmap
Client optics
 Current LR4 generation is the CFP2 with CFP4 soon coming
 CFP2 client optics are a 100G network enabler: lower power, lower cost and
higher density
25G I/O (or 10G)10G I/O
10 physical
electrical lanes
LR4 to 4 λ
CFP2
4 physical
electrical lanes
LR4 to 4 λCFP
CFP CFP4
(2015/2016)
CFP2
Now
Already in alpha/beta
version
LR4
LR4 &
SR10
SR10
CXP
QSFP28
(2016)
• CFP2/CFP4 for telecom for increased
power & distance
• QSFP28 for data center for small size &
low cost
CPAK

Compare to 10GE
 A lot of form factors for 100GE to optimize
 There were even more for 10GE!
2000 2010
300-pin MSA
XFP
SFP+
Xenpak
X2
XPAK
25GE (802.3by)
SFP28

Data Center Growth: 100G
 Data Center core moving to 100G
• Fueling the development of 25GE interfaces to Top of Rack Switches
• Strong need for low cost client interfaces
Infonetics 10G/40G/100G
Optical Transceivers Oct. 2014

100GE Client Connectivity Needs
 Data Center
• Backbone (inter-building) connects MDF (Main Distribution
Frame) to MDF. SMF between buildings
• In-building MDF connects to Distribution Switches
- 100m is often too short a distance
- 10km is too costly
- Ribbon cables becoming common
 Telecom
• Current 10 km interface reaches most customers – not all
• Key metro distance of 20 km+ becoming a requirement
- Need 20km to 40km interface
Costly optics have kept 100G out of the datacenter – this is
about to change

Upcoming 100GE Client Interfaces: 1 to 3 years away
 Considerations for new interfaces based on 25G I/O for data
centers:
• 100GBASE-SR4 (802.3bm)
- Four lanes on MMF 100 m. Key innovation is use of FEC RS(528,514)
at PCS layer
• 100GE PSM4 (PSM4 MSA)
- SMF in the 1310 nm range for target distance of 500 m (also uses FEC)
• 100GE CWDM4 (CWDM4 MSA) & CLR4 & OpenOptics
- Discussions around 2 km range interface for SMF
 In addition the following are being mentioned:
• 100GE ER4-lite
- Similar to ER4 for 40km but with use of FEC at PCS layer
Clear migration to all x4 interfaces for 100GE
SR4 125m
PSM4 500m
CWDM4 2km
CLR4 2km
OpenOptics MSA 2km+

Medium Dependent Interface
Physical Medium Dependent
Reed Solomon Forward Error Correction
Physical Medium Attachment
Physical Coding Sublayer
(100) Gigabit Media Independent Interface
Logical Link Control
Media Access Control
From IEEE 802.3bj
Reconciliation Sublayer
Layer 1
Layer 2
Layer 3
Layer 4
Physical
Data Link
Network
Transport
OSI Model
Medium
MAC
RS
100GBASE-SR4
PMD
PMA
MDI
RS-FEC
CGMII
LLC
IP
100GBASE-R PCS
SR4 100GE Sublayers
• MM fiber at 25Gb/s has a lot of dispersion causing ISI, a FEC is
required to get a link to work
• The same FEC block is used for passive copper, backplanes,
SR4 and PSM4/CWDM4/CLR4/ER4-lite

RS-FEC
 RS(528,514) used for 100GEBASE-SR4 (and KR4 and CR4),
PSM4, CWDM4, ER4-lite
- Symbol size of 10 bits
- 7 correctable symbols per FEC block
- 14 detectable symbol errors
 Use of 64b/66b PCS to 256b/257b transcoder for RS-FEC layer
(maintain throughput)
• Such that the 100GE information rate remains 103.125 Gbits/s (25G per
lane)
Error Correction extends transmission distance for 25Gb/s lanes
…
Redundant area (14 symbols) Message area (514 symbols)
FEC Block (528 symbols)
symbol symbol symbol symbol

PSM4
 Industry Consortium Group
• Avago, Brocade, Delta Electronics, Finisar, JDSU, Juniper, Luxtera,
MACOM, Microsoft, Oclaro, Panduit, US Conec
 Low cost solution to extend reach within data center for
100Gbps interconnects
 Reach of 500m on parallel (ribbon) single mode fiber
infrastructure
• Sufficient within many data centers
• Max power per lane: 2dBm, total of 8 dBm
 Use of digital FEC to keep costs down

CWDM4 & CLR4
 CWDM4 targets a common specification for low cost 100G
optical interfaces up to 2 km
 Data center applications
 Uses Coarse WDM technology with 4 lanes of 25 Gb/s on SMF
 CLR4 has similar targets to above at same wavelengths
 CWDM4 and CLR4 to interwork with CLR4 FEC on
 Universal concept
• Module convertible between SMF and MMF (shorter distance)
• Can be aligned to CWDM4 wavelengths
CWDM4 CLR4
Tx Max power per
lane
2.5 dBm 2.5 dBm
Rx Min power per
lane
-11.5 dBm -12.5dBm (with FEC)
-10 dBm (no FEC)
FEC Yes Yes or No
1217nm 1291nm 1311nm 1331nm

ER4-Lite
 Key goal is to enable Metro and business services
deployments with longer reach client interface
 Current ER4 IEEE 820.3ba standard exists for 40km
• No FEC
• Technically challenging
 Concept of ER4-Lite
• Similar to ER4 BUT with potential use of RS(528, 514) FEC to
reach 40km
• Proposed APD based specification for 40km reach

Connectivity
 SR10
- MMF ribbon, 10Gb/s
- 24 fibers: 10 active/dir
- Flat MPO/MTP connector
 SR4
- MMF ribbon, 25Gb/s
- Flat MPO/MTP connector
 PSM4
- SMF ribbon, 25Gb/s
- Angled MPO/MTP connector
 CWDM4 / CLR4
 Duplex SMF, 25Gb/s / λ
 LR4/ER4
- Duplex SMF, 25Gb/s / λ

Data Center Form Factor Challenges
 In 1st gen 100G switches and routers, the smaller CXP form factor
was used with MMF ribbon cables (SR10)
 CFP or CFP2 is used for SMF transceivers
 This forced compromises as CXP ports could not be used with
SMF
 The QSFP28 form factor is set to resolve this dilemma
• A 1 rack-unit (RU) switch can accommodate up to 36 QSFP ports on
the front faceplate
CXP
CFP

Generic Industry Roadmap
CFP CFP2 CFP4 QSFP28
Now
t
LR4 SR10 LR4 SR10
LR4
LR4
This is approximate to give a general idea of interface vs. form factor
This does not represent the view of any specific optics vendor
ER4
ER4-lite
ER4-lite
SR4
SR4 PSM4
CWDM4
CWDM4
Telecom
Data Centers
ER4

 QSFP28 increases front-panel density by 250% over 40G QSFP+
• Lane speeds are increases 2.5-fold from 10 Gbps to 25 Gbps
• Both are the same form factor
 The increase in density is also considerable compared to other
100G form factors
• 280%+ versus CFP2
• 146%+ versus CFP4
Front Panel Relative Density
4 x CFP
8 x CFP2
16 x CFP4
24 x QSFP28
Belly-to-belly

What about Coherent Pluggables?
Slowly becoming available
Benefit is to have single line card supporting line
or client interfaces
 CFP & CFP2 exist for LR4, ER4, SR10
 Coherent pluggables to support DP-
QPSK; currently available
 CFP
• Common digital interface
• Large pluggable size
 CFP2
• Smaller, lower cost optics
• Challenging electrical bus with off-optics DSP
Complex analog interface
DSP to
interoperate with
multiple CFP2
vendors
CFP2DSP
Decoupled CFP2
Integrated CFP
Unit
Common digital
interface
DSP CFP
Unit

Testing Pluggable Optics: Anatomy of Requirements
R&D and qualification
require COMPLIANCE testing
Field Troubleshooting
requires PERFORMANCE checking
Compliance
Check pattern sensitivity and crosstalk
across lanes
Dynamic skew
Clock Tolerances, nominal jitter
Verify receiver sensitivity
Functionally verify communications with
optics module (MDIO)
Electrical bus signal control
Performance
Focus on Error Rate performance
Test within clock tolerances
Verify operation within specified optical
power range
CFP
CFP2
Get acceptable error rate performance Validate designs
Note: Skew testing does not add to field
test reliability – not required
CFP4QSFP28

BERT Testing Optics
Performance Test times depend on 3 factors:
- Data Rate
- Confidence Level
- BER Threshold
95% CL 100GE
BER Sec Min hrs
1E-12 29.09 0.48
1E-13 4.85
1E-14 48.48 0.81
1E-15 8.08
Bit Error Rate Test Time for a 95% Confidence Level depends on the line rate
and BER target:
99% CL 100GE
BER Sec Min hrs
1E-12 44.6 0.7
1E-13 7.4
1E-14 74.3 1.24
1E-15 12.39
New element with RS-FEC interfaces
 Pre-FEC tests (error rate BEFORE applying FEC)
 Post-FEC results (error rate AFTER FEC correction)

Compliance Testing Examples
Crosstalk
patterns
Dynamic
Skew
Frequency
Variations
Electrical
bus pulses

Line Side Impairment Testing
CLIENT SIDE (IEEE) LINE SIDE (ITU/OIF)
100GE Client 100G Coherent
Optical Stress
Data + Optical Stress
Loop traffic on MAP
Measure OSNR Penalty - OSNR is the new
measure of distance
 Control Loss via attenuator
 Manipulate OSNR via ASE source & EDFA
Scramble polarization – fiber emulation
Simulate ROADM Network
 Perform optical filtering to affect signal
shape
Simulate Fiber
 Scramble polarization
Run 100GE BER tests
- Error Rate Results
JDSU ONT
or
MTS/T-BERD
JDSU MAP
For all tests, error evaluation through BER results

400GE Client Considerations
400GE Client under discussion at IEEE 802.3bs
 Discussions include 8 lanes @ 50G and 4 lanes @ 100G
 2015 view toward 2017 standard – All unconfirmed
• 400GBASE-SR16 & PSM4 (or 8) for data centers
• 400GBASE-LR8 for telecom
• Use of higher order modulation (HOM) both electrical & optically
- PAM-4 => adopted March 2015 for electrical interface
• Ethernet-level FEC mandatory
- No more error free native links – can assume < 10^-6 pre-FEC BER!
Media Interface Electrical Lanes Optical
Modulation
MMF 100m 400GBASE-SR16 25G-per fiber NRZ
SMF 500m 400GBASE-PSM4 100G-per fiber PAM-4
SMF 2km 400GBASE-FR4 50G-λ PAM-4
SMF 10km 400GBASE-LR8 50G-λ PAM-4

Per Fiber Type Summary
Courtesy Ethernet Alliance

400GE Pluggable Form Factors under Considerations
 Possible 400GE pluggable optics:
• CDFP, mostly for active cables (short distance)
• Telecom form factors undecided
- Possibly will use CFP2
• May land on a CD-QSFP (QSFP sized) form factor in the very
long run

Early Test Products
 400GE module on ONT
 Demonstrated at OFC 2015
 Pre-standard 400GE based on 25G I/O – 4xCFP2
 Design to accelerate 400G product development, validation
and inter-operation

Optics for 100G and beyond

Recommandé

Recommandé

Contenu connexe

Tendances

Tendances (20)

Similaire à Optics for 100G and beyond

Similaire à Optics for 100G and beyond (20)

Plus de CPqD

Plus de CPqD (20)

Dernier

Dernier (20)

Optics for 100G and beyond