Test Solutions for the 400G Data Center Evolution

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

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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


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


(1) (2) (3)

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https://multilaneinc.com/solutions_services/i2c-cmis-analysis/

Host Compliance Boards - HCBs

Gain access to all high-speed Tx and Rx signals


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


Block Diagram

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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 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


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

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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


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


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


ML4054B: 400G FEC BERT with Integrated MCB

KP4 SER Histogram

https://multilaneinc.com/solutions_services/fec-testing/

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


ML4054B

Thermal Stream

ML4054B 400G BERT demo


THANK YOU

What is next? 800G


OFC 2021


Learn more:

MultiLane booth

#1435

Test Solutions for the 400G Data Center Evolution

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