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Test Solutions for the 400G Data Center Evolution
Webinar
Kees PropstraMay 26th, 2021
Technology Evolution
400G Data Center Evolution
Special thanks to Vladimir Kozlov @ Lightcounting
400G Host Testing Snapshot
3
ASIC
Trace SI TroubleshootingIs ASIC-to-port path free of impedance mismatches?
Interoperability
CMIS ComplianceIs module management robust enough for stateful host/pluggable interactions?
Diagnostic ValidationCan ASIC execute diagnostic functions like shallow loopback, PRBS and reporting of FEC statistics?
RX ToleranceCan ASIC recover noisy/jittered input signal?
TX ComplianceIs transmit signal quality consistent from port to port?
Thermal Loading
Port ValidationCan port function as expected and regulate pluggable temp?
Port validation
How to validate the proper operation of your system port?▪ Can the port recognize a transceiver? CMIS compatible?
▪ Sufficient Signal Integrity?
▪ Can the system support the intended thermal/power load?
Loopback/thermal loads▪ SI traces loopback Port TX into RX
▪ MSA Housing Compatible▪ QSFP-DD, OSFP, QSFP28, etc.
▪ Programmable power dissipation▪ Up to 30W QSFP-DD800 / OSFP 800
▪ Fully customizable – emulate your Data Center Interconnect
400G Data Center Evolution
Adapters + CMIS Analyzers
▪ Validate host/module implementation of Common Management Interface Specification
▪ Certify that parameters like optic DOM and ID, errors and alarms are monitored correctly on host
▪ Pass/Fail state machine test - see top right
▪ Monitor and save I2C transactions between host and pluggable
▪ Force host alarms (high/low/tri-state)
▪ Enable versatile CMIS testing in three modes:
1) Master mode: Analyzer behaves as a host for a module DUT
2) Slave mode: Analyzer behaves as a module for a Switch DUT
3) Bypass/Sniffer mode: Analyzer reports on communication between module and switch
▪ Learn more by visiting our website
400G Data Center Evolution
(1) (2) (3)
5
Host Compliance Boards - HCBs
Gain access to all high-speed Tx and Rx signals
400G Data Center Evolution
ML4064-HCB Insertion Loss
Test Applications:▪ Switches▪ Routers▪ Transponders▪ Server NICs (Network Interface
Cards)
MULTILANE CONFIDENTIAL
Is Host Port spec compliant and robust enough?
▪ SI margin testing
▪ Hi-speed lane access
▪ Noise injection
▪ Shallow loopback
Host Characterization
400G Data Center Evolution
Block Diagram
7
Port Troubleshooting
▪ Loopback test indicates SI problem – high BER
▪ Impedance measurements help identify source of problem
▪ The ML4035 enables TDR Testing for port debug:▪ Isolate impedance mismatches and discontinuities▪ Pass/Fail verdict for each lane▪ Gated TDR enables hone-in on fault area
(for instance, a bad connector or broken pin)▪ Sub ohm accuracy▪ ~1 mm resolution
400G Data Center Evolution
400G Module Testing Snapshot
Comprehensive Validation Required
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ComplianceIs pluggable compliant with
OpenEye/IEEE guidelines?
CMIS ValidationIs module conforming with
the target CMIS version?
Corner TestingIs the transceiver compliant over
voltage and temperature spec limits? Electrical Optimization
Which electrical equalization profile leads to optimal optic performance?
Real FEC AnalysisWhat is the module SER performance with real FEC
encoding?
400G Transceiver Tester
Fully automated transceiver tester
▪ Incoming inspection
▪ Failure analysis
▪ RMA testing
Tests Performed
▪ Optical Eye Diagram
▪ Extinction Ratio
▪ RX Sensitivity
▪ Waterfall Curve
400G Data Center Evolution
ML7007-400G
Test Report User-friendly GUI
▪ Pass/fail test report at the push of a button
▪ No Optics PhD required
400G DAC Characterization
ML1105 – Automated Cable Test Solution
▪ TDR and S-parameters:▪ Impedance profile
▪ Return loss (S11)
▪ Insertion loss (S21)
▪ Crosstalk (NEXT, FEXT)
▪ ML1105 Automated software for production/RMA
▪ Manual software for debugging and verifications
▪ Channel Operating Margin (COM)
▪ AECs and ACCs – please stay tuned
11
Module Compliance Boards - MCBs
▪ User-friendly GUI for I2C R/W commands and loading custom MSA Memory Maps
▪ Gain access to all high-speed Tx and Rx signals
▪ Compliant with CEI-56G-VSR
▪ DUT voltage supply control
▪ DUT current sense
▪ Temperature monitor
▪ On-board LEDs showing MSA output alarm states
400G Data Center Evolution
Test Applications:▪ Optical Modules/Transceivers▪ Direct Attach Copper Cables
(DACs)▪ Active Optical Cables (AOCs)
ML4041K-56 Insertion Loss
MULTILANE CONFIDENTIAL
TX/RX Equalization Optimization
Optical Modules, AOCs and DACs encounter new challenges at PAM4 rates
▪ Power consumption is key - optimization of power consumption yields significant cost savings
▪ MultiLane BERTs support fine-tuning of TX and RX EQ to trade-off BER performance and power consumption for both hosts and pluggables
400G Data Center Evolution
7-Tap TX Equalization
RX EQ and Diagnostics
EQ Optimization using ML BERT
Moduleoptimization
Switchoptimization
Real Hardware FEC Analysis
PAM4 systems rely on Forward Error Correction to stabilize erroneous links
▪ ThunderBERT supports Real Hardware RS-FEC Analysis
▪ Correctable/Uncorrectable Codeword count
▪ SER Histogram
▪ Encoding/Decoding of real FEC blocks gives most accurate performance margin of 400G/800G components, optics and hosts
▪ FEC White Paper link
400G Data Center Evolution
ML4054B: 400G FEC BERT with Integrated MCB
KP4 SER Histogram
Multi-Corner Testing
▪ Stress a DUT transceiver by validating compliance at high/low operational corners of voltage and temperature
▪ The ML4054B includes an integrated host with variable supply voltage control
▪ To achieve desired temperatures two setups are available:
❖ ML4054B with external mounted thermal stream
❖ ML4054B-LP featuring same hardware inside a special enclosure that mounts on a custom door of a TestEquity temperature chamber
MULTILANE CONFIDENTIAL 15
400G Data Center Evolution
ML4054B
Thermal Stream
ML4054B 400G BERT demo
400G Data Center Evolution
THANK YOU
What is next? 800G
400G Data Center Evolution
OFC 2021
400G Data Center Evolution
Learn more:
MultiLane booth
#1435
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