100g technology

7/26/2019 100G Technology

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12010 EXFO Inc. All rights reserved..

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Testing Challenges ofHigh Speed Networks


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2

High Speed Market

Overview


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32011 EXFO Inc. All rights reserved.

High Speed Market Drivers

BBC iPlayer

Higher quality than YouTube

10 x longer viewing

30 x more bandwidth

Internet Video

YouTube uses 200TB daily

- as much as the entire

Internet did in 2000.

Video Calling

10x more bandwidth as we

move from phone to video

conversations

Mobile Data & Video

Apple sells 1 million iPhone

4S in 1 day, all supporting

video features.

HD TV

Upgrades to HDTV will

increase IPTV bandwidth

five-fold


4/6642011 EXFO Inc. All rights reserved.

Application Growth

400% Internet video growth

92% mobile data compound annual growth

Source: Cisco VNI



Wireless Backhaul

80% Operators: strategy to move to all-IP/Ethernet Backhaul

82 %Ethernet Backhaul connection by 2015

$6.4B Ethernet Backhaul 2011 (93%) 50% of failures take place in the backhaul

1/3 OPEX technical operation

Ethernet offers compelling economics for Mobile Backhaul and

creates a demand for higher bandwidth at the core


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High Speed Optical Transceivers

1H/2011 100G revenue shipments totaled $35 million

From 2010 through 2015, the total market, including 100G, will grow at a CAGRof 16% to reach $2.6 billion in CY15

Technology is now commercially available from most NEMs: Ciena, NSN, ALU,

ZTE, Cisco


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High Speed Optical Transceivers



100G Within The Network

Core ingressClient Core

Client side

Faces customerService oriented

Standardised parallel optical interface

40 Gbit/s & 100 Gbit/s

Ethernet, OTN evolutions

Line Side

Toward transport core networkTransport oriented

Serial optics - mostly DP-QPSK coding

OTN mandatory


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100G EthernetClientSide


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100G Within The Network - Client Transceivers

CFP form factor package (86x127x14 mm / 3.4x5.0x0.55)

ER4 100 GbE, 40 km on SMF (4x 25G WDM, centered at 1305nm)

LR4 100 GbE, 10 km on SMF (4x 25G WDM, centered at 1305nm)

LR4 40 GbE, 10 km on SMF (4x 10G WDM, centered at 1305nm)

SR10 100 GbE 100m on MMMF (850nm parallel optics, 10x 10G)

LR10 100 GbE, 10 km on SMF (10x 10G WDM, centered at 1550nm, not yet standardised)

CXP form factor (approx 20x54x11 mm / 0.78x2.13x0.43)

100 GbE, 100 m on OM3 MMF (850 nm parallel optics, 10x 10G)

100 GbE, 10 m on active cable

QSFP form factor (18.4x72x8.5 mm / 0.72x2.8x0.33)

40 GbE, 100m on OM3 MMF (850 nm parallel optics, 4x 10G)

40 GbE, 10 m on active cable


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40G Ethernet (40G Base R)

100G Ethernet (100G Base R)

40G OTN (OTU-3)

100G OTN (OTU-4)

Transport class client side


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100G Technology Challenges


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100G EthernetLR4 Example

100G Media Independent Interface

(CGMII)

100G Attachment Unit Interface

(CAUI)

Medium

Media Access Control (MAC)

Reconciliation Sublayer

Physical Coding Sublayer (PCS)

Physical Medium Attachment (PMA)


Physical Medium Dependent (PMD)

Pre. Dest. MAC Src. MAC EtherType Payload FCS IPG

64b/66b line

coding

including

sync. header

n

2

1

0


191817161514131211109876543210

Round robin block

distribution

20 PCS lanes

Incoming

Ethernet

frames

AM

19

AM

18

AM

17

AM

16

AM

15

AM

14

AM

13

AM

12

AM

11

AM

10

AM

9

AM

8

AM

7

AM

6

AM

5

AM

4

AM

3

AM

2

AM

1

AM

0


DC-balanced

alignment markers

every 16383 blocks

Remove some IFG

for AM use



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(CGMII)


(CAUI)

Medium







191817161514131211109876543210


64b/66b line

coding

n

2

1

0


Round robin block

distribution

20 PCS lanes

Incoming

Ethernet

frames

AM

19

AM

18

AM

17

AM

16

AM

15

AM

14

AM

13

AM

12

AM

11

AM

10

AM

9

AM

8

AM

7

AM

6

AM

5

AM

4

AM

3

AM

2

AM

1

AM

0


DC-balanced

alignment markers

every 16383 blocks

Remove some IFG

for AM use



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(CGMII)


(CAUI)

Medium







191817161514131211109876543210


64b/66b line

coding

n

2

1

0


Round robin block

distribution

20 PCS lanes

Incoming

Ethernet

frames

AM

19

AM

18

AM

17

AM

16

AM

15

AM

14

AM

13

AM

12

AM

11

AM

10

AM

9

AM

8

AM

7

AM

6

AM

5

AM

4

AM

3

AM

2

AM

1

AM

0


DC-balanced

alignment markers

every 16383 blocks.

BIP included

Remove some IFG

for AM use



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(CGMII)


(CAUI)

Medium







191817161514131211109876543210 20 PCS lanes

0 1 2 3 4 5 6 7 8 9

PMA 20:10

10 electrical lanes

(bit-interleaved)

0 1 2 3

PMA 10:4

4 optical wavelengths

Optical Mux

Gearbox

T

X

T

X

T

X

T

X CFP



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4 x 25G & 10x10G CFP Comparison

0 1 2 3

Optical Mux

Gearbox

T

X

T

X

T

X

T

X

4 Optical Lane CFP 10 Optical Lane CFP

T

X

T

X

T

X

T

X

T

X

T

X

T

X

T

X

T

X

T

X

0 1 2 3 4 5 6 7 8 9

28 Gbit/s per optical channel

Utilises Gearbox

High power requirements

12 Gbit/s per optical channel

No Gearbox requiredreduced complexity & cost


Optical Mux


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Skew

191817161514131211109876543210

0 1 2 3 4 5 6 7 8 9

0 1 2 3

Optical Mux

Gearbox

T

X

T

X

T

X

T

X

191817161514131211109876543210

191817161514131211109876543210

RX

RX

RX

RX

0 1 2 3 4 5 6 7 8 9

Gearbox

19

1817

16

15

14

1312

11

10

9

8

7

6

5

4

3

2

1

0

19

1817

16

15

14

1312

11

10

9

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3

2

1

0

19

1817

16

15

14

1312

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10

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5

4

3

2

1

0

Optical Mux

0 1 2 3

13 1614119

75

1 193

193

75 6

S

kew

Skew is measured per PCS lanefrom the first block being received

Skew unavoidable in thisarchitecture

Up to 928 bits skew per lane error-free



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Key Concepts

CAUI100G Attachment Unit Interface

10 lane electrical interface to CFP module

CFP100G Form-factor Pluggable

Support multiple media interfaces including 4, 10and other media

Skew

Lane specific delay at the receiving end of a link

Each lane will tolerate up to 928 bits of skew



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CFP Evolution


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PCS V tilit


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PCS Versatility

Why use the 20 lane PCS?

To allow for future interfaces to physical modules

Can be multiplexed to lower lane-count interfaces

4 x 28G Electrical interface

Reduces complexity of optical module

Complex electrical interface

Reduced power requirements

Reduced module size

CFP2 interfaces under study

191817161514131211109876543210

0 1 2 3

T

X

T

X

T

X

T

X

Optical Mux



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CFP D l t


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Line card

ASIC

CFP Developments

T

X

T

X

T

X

T

X

Optical Mux

CFP2

CAUI

CFP2

12W max power consumption

1.6 x 5.2 form factor

>50% size reduction

2 x port density of CFP

50% power reduction

Gearbox moved to line card

CPPI-4 interface4 x 28Gbit/s

Gearbox

CPPI-4



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CFP Developments


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CFP Developments

Each generation ofCFP reduces form

factor and powerconsumption by 50%



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OTU4 100G OTN


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OTU4100G OTN

OTU-4

ODU0ODTU-4.1x80

ODU1ODTU-4.2x40

ODU2 / ODU2eODTU-4.8x10

ODU3ODTU-4.31x2

ODUflexODTU-4.tsx80/ts

ClientOPU4

(L)

ODU4

(L)

ODU4

(H)

OPU4

(H)

ODTUG4

(PT 21)

OTU4112Gb/s line rate

Extends previous OTN multiplexing structure

100G

Ethernet

GMP



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Nomenclature


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Nomenclature

OTLOptical Channel Transport Lane indicates a multi-lane interface

Usage OTLx.y

xindicates the speed of the multilane interface

yindicates the number of parallel lanes

Examples

OTL 4.4OTU4 over 4 parallel lanes

OTL 4.10OTU4 over 10 parallel lanes


Logical Lanes


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OA

2OTU Overhead

ODU Overhead

OPU OH

OA

1

OA

1

OA

1

OA

2

OA

2

Logical Lanes

191817161514131211109876543210

Round robin block

distribution

20 logical lanes

IncomingOTN frames

FECClientOH

FECClientOH

16 byte

blocks

n

2

1

0

5

4

3

OA

2

3rdOA2 byte used as Logical LaneMarker (LLM)

Different from Ethernet in that the

parallel lane management overheadsare kept within the frame



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Skew


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OTN can tolerate higher levels of skew than Ethernet

LLM cycles through 240 values

Lanes can be identified and recovered as long as skew does not exceed 119 frame periods

Possible to extend the skew recovery further by combining the MFAS with the LLM, allowingup to 1919 frame periods of skew (over 2ms)

Skew tolerance 100G Ethernet 100G OTN 100G OTN with MFAS

Data 928 bits 1942080 bytes 31318080 bytes

Time 180ns 139 s 2.241 ms


Key Concepts


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y p

Supports OTN multiplexing structure

112Gbit/s bit rate

Uses similar 20 lane concept to 100G Ethernet

Uses 20 logical lanes identified by LLM for recovery and skew

Supports either 10 lane or 4 lane interface

Higher skew tolerance then 100G BaseR



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Test Requirements


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Common key test requirements for OTN & Ethernet

PCS / Logical lane testing

Verify correct recovery of the parallel interface and PCS/LL to physical lanemappings

Verify error free performance of multi-lane interface with multi-lane BER

testing

Physical lane testing

Crosstalk

Skew testing

Check received skew is within design thresholds

Generate skew to identify skew tolerance thresholds



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100G Within The NetworkL2 and also L3/L4 testing


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100G L2 Network Testing

100G L3/L4 Network Testing


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Physical Layer Testing


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PCS lane Testing

100G CAUI testing PCS lane mapping Per-lane skewgeneration/analysis MDIO read/write

Per Lane BERT

Configurable PRBSpatterns per laneUsed for CAUI laneseye diagram testingto identify crosstalkissues

Power Measurement

Per

receivedoptical powermeasurement Per power levelcontrol & laserON/OFF

Signal Conditioning

Used tocharacterize CAUIlanes. Troubleshootingcapability forelectrical-levelissues on standardoptical interfaces



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Physical Layer Testing


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Error & alarmmeasurement of PCS /LLM conditions

Configurable skew

threshold alarm


Ethernet Testing


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EtherBERT

100GE BERT 100G layer2/3 Alarms and errors Ethernet statistics

RFC2544

Throughput, B2B,latency & frame loss Standard &customizedRFC2544 framesizes RFC2544 at full linerate

Smart Loopback

One-click loopback Returns traffic tolocal unit byswapping packetoverhead Flexible loopbackmodes to simplifyinterop. testing

Packet Capture

Full line-rate captureOffers capture filtersand triggers to quicklyzero-in on networkeventsCapture in PCAP &read throughWireshark

Filtering

Advancedtroubleshootingcapability Ten userconfigurable filters Detailed statisticsfor each configuredfilter



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100G Coherent Line Side

Line Modulation


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Line speed Modulation methods

Up to 10Gbit/s Amplitude

40Gbit/s Phase or amplitude

100Gbit/s and beyond Phase or Phase & Amplitude

Why use phase and amplitude based modulations? Increase spectral efficiency (allowing higher data rate)

Reduce non-linear effects


A Brief History Of Line Modulation


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1 0 0 1 1

t

Amplitude

On/off keying(OOK)

Return to zero (RZ)

Amplitude modulation

One bit encoding

t

Amplitu

deOn/off keying(OOK)

Non-return to zero (NRZ)

Amplitude modulation

One bit encoding

t

AmplitudeBinary phase-shift

keying (BPSK)

Phase modulation

One bit encoding

t

AmplitudeDifferential phase-shift

keying (DPSK)

Phase shift modulation

Phase shifts on a 1 bit

One bit encoding



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Polarisation Multiplexing


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Polarisation multiplexing (PM), also called Dual Polarisation (DP)

Doubles the capacity of a span by encoding the information on two different

polarizations

Vertical polarisation

Horizontal polarisation

Dual polarisation

Polarisation Multiplexing


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DP-QPSK often used to reach 112Gb/s speeds

112Gb/s bit rate with a 28Gb/s symbol rate

QPSK Modulator

28Gb/s

1 bit per symbol

28Gb/s

1 bit per symbol

QPSK Modulator

28Gb/s

1 bit per symbol

28Gb/s

1 bit per symbol

28Gb/s

2 bits per symbol

M

P

28Gb/s

2 bits per symbol

28Gb/s

4 bits per symbol

Spectral Efficiency


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Using polarization multiplexing

combined with QPSK allowstransmission of 112 Gbit/s onchannels with 50 GHz ROADMs 112 Gbit/s NRZ-OOK

112 Gbit/s NRZ-QPSK

112 Gbit/s NRZ-DP-QPSK

Guard Bands


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Ideally all traffic would fit into a

50GHz spaced system

Effects have been observedbetween DP-QPSK and adjacent10G channels

Guard band typically usedbetween phase modulated andnon-phase modulated channelsto prevent issues

Guard band is a spacing of200GHz400GHz between thedifferently modulated channels

Key Concepts


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Phase shifted modulations

Increased bits per symbol

Increased spectral efficiency

Can be used to deliver past 100Gb/s

Polarization multiplexing

Doubles the symbol rate by multiplexing two polarized modulation carriers

DP-QPSK most common method of delivering 112Gb/s line side

DP-QPSK only 28Gbaud line rate with 4 bits per symbol

Guard bands

Used between phase shifted and non-phase shifted channels to prevent cross-phasemodulation


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The Future

Past 100G


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What is the next bitrate after 100G?

Currently there is still debate whether the next step is 400Gbit/s or 1Tbit/s

Once the bit rate is decided the client interface can be achieved through changing the lane width (number oflanes) and the lane speed

Coherent signaling can be used at 400Gbit/s and 1Tbit/s

50GHz dual carrier (400Gb/s) or 100GHZ super carrier (1Tb/s) under investigation

8 bits per symbol using DP-16QAM modulation

ITU study groups investigating OTU5

Bitrate to be based around the next Ethernet client

Needs to efficiently multiplex current ODU tributaries (Eg. 10xODU-4, 25xODU3 into ODU5)

Parallel optics possibilities at 1Tb/s:

40x25.78Gb/s, 25x40.13Gb/s, 20x51.56Gb/s, 10x103.125Gb/s

Need new client interface definitions


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100g technology

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