100gbps for nexgen content distribution networks for nexgen content distribution networks martin...

100Gbps for NexGen Content Distribution Networks

Martin ZirngiblDomain leader, Physical Technologies, [email protected] Labs Research

2 NANOG45, January 2009

Market Drivers for 100GDigital video trunking:

Part of growing “triple play” consumer packagesVideo bandwidth is easier to monetize(compare with p2p traffic)Requirement for high definition drives− High data rates per channel− Transport of uncompressed video for

access network specific compressionExplosive growth in programming content(estimated ~90% of BW in NG networks)

Video traffic:Requires minimal latency for effective deliveryRequires resilient transport (MPLS and transport layer)Benefits from multicast and from “asymmetric” design

Other factors: storage networking, carrier wholesaling, science applications, grid computing

What’s behind the growth?

VoIP

Enhanced Internet Services

Triple Playbundle

IPTV(incl. HDTV, VoD)

Blendedvoice,video& data

services

2000 2005 today Coming soon

MoreBandwidth

!MoreBandwidth

!!

ContentsourceBroadcast

CATV

IP TV

MPLS/Optical for video trunking


NexGen Ethernet will be 40GbE and 100GbE

1980 1985 1990 1995 2000 2005 2010

0.01

0.1

1

10

100

10 Mb/s

100 Mb/s

1 Gb/s

10 Gb/s

Year

100 Gb/s

Today: 10 GbE

Good support for 100GbE in standards

IEEE to adopt a OTN compatible standard for 40GbE/100GbEIEEE and ITU-T timelines target mid-2010 for standards completion

Service providers and equipment OEMs also support 100 GbE

100G transport cost effective compared to 10G

A side-effect will be that 40G transport will also become more cost-effective as 100G techniques begin to be implemented in 40G

transmission


10G I/O10G I/O10G I/O10G I/O10G I/O10G I/O10G I/O10G I/O

Benefits of 100G Networking10G interfaces 100G interfaces

10G 100G

On high-end core routers: Fabric capacity is poorly utilized with lower speed I/O (*)

Better utilization of fabric bandwidth due to improved access into it

(*) Example: Juniper T-1600

10G10G10G

10G10G

10G10G

10G10G10G

10G10G10G

10G10G

10G10G

10G10G10G

On high-end core routers: 10 x 10G interfaces subscribe 100G of BW

100G100G

The price of 100G interface on router will be much lower than 10 x 10G for the same capacity

A higher speed wavelength is better able to accommodate peak BW

Much larger LAG BW!!

Smaller wavelengths limit BW bursts

LAG groups are limited to 17 members

Large wavelength count consumes DWDM grid, represent higher cost for “commons”

Efficient use of DWDM grid.

No parallel wavelengths means lower OAM cost and fewer managed entities

100GN x 10G

100G I/O

100G I/O

100G I/O

100G I/O


The boundary conditions of capacity growthGrowth of transport requires

Higher spectral efficiency or

Wider amplification bands or

Light another fiber

Latter two often too costly

Growth may have to be accommodated in existing systems

50-GHz channel spacing

Multiple ROADMs

Optical Reach

Capacity Growth based on 100G with advanced modulation format will lead to

very high spectral efficiency and be compatible with existing systems


~112 Gbaud ~56 Gbaud ~28 Gbaud

1 bit/symbol 2 bit/symbol 4 bit/symbol

Required OSNR

Tolerance to CD, PMD, Filtering (in ROADMs)

Complexity of implementation

Tx

Rx

MZI-based Tx

NRZ/RZ Detector

I

Options for DQPSK

detection

DQPSK Tx

Polarization Multiplexing /

DQPSK TxLaser

Data

CDR

Coherent PM/DQPSK

detector

Multi-level Modulation Formats in Optics

/2π /2πLaser

I

Q

/4π /4π- CDR

DBSK Detector

/4π+ /4π+-

-

I

Q

CDR

/4π− /4π−

/2π

PBS

/2π

I

Q

I

Q

X

Y

Laser PBS

- CDR

- CDR

ADC+

DSP

OLO

hybrid2π hybrid2π

-

-

PBS

hybrid2π hybrid2π

-

-

hybrid2π hybrid2π

Rx

PBS ADC

+

DSP

OLO


100 Gb/s serial modulation format choices

50 … 100 GHz

± 50 ps/nm

~ 10 ps

40G(Binary)

25 … 50 GHz

± 800 … 2000 ps/nm

~ 40 ps

10G(Binary)

Very large(coherent,

oversampled)± 26 ps/nm± 25 ps/nm± 8 ps/nm

CD tolerance(2-dB penalty)

50 GHz100 GHz150 … 200 GHz150 … 200 GHzSupported gridw/ ROAMDs

Very large(coherent,

oversampled)

100GPDM-QPSK

~ 8 ps

100G(RZ-)DQPSK

~ 3 ps

100GDuobinary

~ 3 psDGD tolerance(1-dB penalty)

100GNRZ

PMD-QPSK … Polarization-mode dispersion quarternary phase shift keyedDGD … Differential group delay

CD … Chromatic dispersionROADM … Reconfigurable optical add/drop multiplexer

~112 Gbaud ~56 Gbaud ~28 Gbaud

1 bit/symbol 2 bit/symbol 4 bit/symbol

Required OSNR / Tolerance to Noise

Tolerance to CD, PMD, Filtering (in ROADMs)


At 100G impact of some fiber propagation effects (dispersion, PMD, single-channel nonlinearities) is so high that decreasing the baud-rate is mandatory

This requires necessarily the use of more complex modulation formats and receiver architectures

The combined use of:

Polarization-Division Multiplexing (PDM)

Quadrature-Phase Shift Keying (QPSK) allows to decrease baud-rate by a factor of four (100 to 25 Gbaud)

Coherent detection + processing to compensate for linear impairments

At 100G, PDM-QPSK does not suffer from nonlinear effects induced by 10G and 40G neighbors

PDM-QPSK having important issues at 40G becomes recommended at 100G!

100G Transmission: Picking the best modulation format

PDMPDM--QPSK with QPSK with Coherent DetectionCoherent Detection offers the best option for 100Goffers the best option for 100G


Support for 100G Multi-wavelength Transmission

Our optical test-bed has shown support for 16.4 Tbpstransmission over 164 channels at greater than 2,500 km

[G.Charlet et al., OFC PDP3, 2008]12

11

10

9

8

7

FEC limit

•7

•8

•9

•10

•11

•12

Q²-

fact

or (

dB)

1525 16051565Wavelength (nm)

Wavelength (nm)

Pow

er (

5dB/

div)

1525 1565 1605

16.4 Tbit/s: 164ch x 111Gb/s over 2,550km

[G. Charlet et al., OFC PDP3, 2008]

FEC Limit

Test-bed for 164 channels

x3

A.O.

GFF GFF

+D +D

-D

GFF

GFF

Tunable filter

5

65km55km

A.O.

PBC

164x100Gb/s 2x27.75Gbit/s

164

wav

elen

gths

Coherentmixer sc

ope

com

pute

r

QPSK

QPSK

2x27.75Gbit/s

CL

CL

LRA

Local oscillator

L

C Booster C

L

C

Booster L

LRA GFF

x3

A.O.

GFF GFF

+D +D

-D

+D +D

-D

GFF

GFF

Tunable filter

5

65km55km

A.O.

PBC

164x100Gb/s 2x27.75Gbit/s

164

wav

elen

gths

Coherentmixer sc

ope

com

pute

r

QPSK

QPSK

2x27.75Gbit/s

CL

CL

LRA

Local oscillator

L

C Booster C

L

C

Booster L

LRA GFF


The Network Evolution Strategy Supporting 100G

IP Access

SONET/SDH

Electrical/Optical Service Aggregation

Transparent (Photonic) Domain

teranode BW management

Direct (colored) optics on

SONET/SDH

OAM&P for SONET/SDH and DWDM

Evolution to 100G is assured through a transparent photonic core which does not hinder introduction of higher bit-rates. Adherence to ITU-T OTN principles ensures non-intrusive wavelength management

Introduction of new capabilities is achieved at the edges through the introduction of transponder (OT) capabilities and enhancements to electrical domain BW management such as the Teranode OXCs

Consolidation of functionality is achieved through integration via a common management and control plane and usage of colored optics on client devices

G.709 OTN for transparency management

Transparent (Photonic) Domain


Impacts of Filters on 100G and Existing Systems

Optically transparent channels see decreasing channel BW after traversing each filter (ROADM, WSS, etc.)

Advanced modulation format allows flexible deployment of 10/40/100G channels

8

9

10

11

20 40 60 80 100

0.2 nm/div

10 d

B/di

v

0.2 nm/div

10 d

B/di

v

Filter width (GHz)

Q²-

fact

or (

dB)

8

9

10

11

20 40 60 80 100

0.2 nm/div

10 d

B/di

v

0.2 nm/div

10 d

B/di

v

0.2 nm/div

10 d

B/di

v

Filter width (GHz)

Q²-

fact

or (

dB)

Our test-beds show− Almost constant performance obtained for

optical receiver bandwidth above 35GHz.− No crosstalk from adjacent channels when filter

width is above 50GHz thanks to coherent detection and sharp filtering provided in the electrical domain

− Conclude that we can expect tolerance to ROADM cascades


100G Transmitter at theTampa Central Office

100G Receiver next to LambdaXtreme®at the Miami Central Office

Tampa to Miami 504-km

field route operating

LambdaXtreme®

100G Field Trial over installed, live Verizon system


100G Field Trial continued

-65-60-55-50-45-40-35-30-25-20

1588.5 1589 1589.5 1590

100G DQPSK

10G OOK

-55

-50

-45

-40

-35

-30

-25

-20

1580 1590 1600 1610 1620

100G DQPSK

10 d

B

1590 1600Wavelength [nm]

Trial included transport of HDTV channel in 100G signal


Fully Integrated Transmitter/Receiver for DQPSK

π/2

Transmitter Receiver

3.2 mm

Eye diagram 107 Gb/s

1.7 mm

37%

37% +90°

225°

submount

Mask Layout

InP chip

Schematics

OFC2008 postdeadline


16 QAM Transmitter for High Spectral Efficiency

EAM based MZM modulator

16-quadrature amplitude modulation (QAM) modulator and demonstrate it at 43 Gb/s(10.7Gbaud)

Scalable to higher rates

4 modulators to drive

Compact 3mm long chip

A BC

D

E

(b)(a)

Data #1 Data #2

Data #3 Data #4

0°180°45°

90°-90°

0.150.30

0.10

0.150.30

Im

Re

OFC2008 postdeadline


Future: 100G Optical Packet Switching Metro Ring Node without WDM

Static optical links between next-neighbor nodes

Requires only one transponder per node

But Thru-traffic reduces add/drop capacity

Scales poorly for large number of nodes N

WDM Metro Ring Node

Static optical links between any two nodes (full mesh)

Eliminates thru-traffic

But requires N – 1 transponders

ROADMs can reduce the number of transponders,but reintroduce thru-traffic

Optical Packet Ring Node

Dynamic optical packet links between all nodes

Requires only one (tunable) transponder per node

Thru-traffic is bypassed, doesn’t reduce add/drop

Adjusts to rapid changes in traffic patterns

Node k

RxTx Processthru-traffic

add drop

Node k

Tx N-1

Tx 1 Rx 1

Rx N-1

Node k

PacketRx

add

Tunable Tx

De-Aggregator

Aggregator

dropk


Optical Packet Switching Demonstration at 10G

OC-12 generator produces scrambled SONET frames with PRBS 231-1 payload

Unused 10 Gb/s time slots are filled with dummy packets

All Tx’s switch packets based on a global, periodic schedule

De-aggreators reassemble packets with SONET data back into OC-12 stream

BER measurements on OC-12 outputs, < 0.5 dB penalty

Span 1: 21 dB, +400 ps/nm. Span 2: 22 dB, -100 ps/nm-23 -22 -21 -20 -19 -18 -17 -16 -15

12111098

7

6

5

4

3

-log

(BER

)

Power @ Rx [dBm]

b2b Tx1-Rx2 Tx2-Rx3 Tx1-Rx3


Bell-Labs fast-tuning laser module

Two double-sided PCB boards, including

FPGA w/ look-up table & microprocessor

Fast D/A converters

TEC controller

Bus interfaces

External wavelength-locker:

ADC is sampled once per packet to update look-up table

Improves frequency accuracy from ±6 GHz to ±3 GHz , correcting for temperature & aging

Feedback is slow (order of seconds)

Switching between all combinations of 64 channels in < 50 ns

Improved laser design and advanced current driving for < 5 ns switching

Not implemented in small module

Accuracy ±12 G

75 mm

GainSource

TEC Control

Laser

Wavelocker

50 mm

75 mm

GainSource

TEC Control

Laser

Wavelocker

50 mm

Microprocessor

ADC

Gain andTemperatureControl and

Monitor

LookupTable

Low

-spe

edR

S232

bus

Hig

h-sp

eed

para

llel b

us DAC

DAC

DAC

Amp

Amp

Amp

Laser

ADC TIA

TIA

DiffAmp

DiffAmp

Wavelocker


Take Away Messages

Video will dominate network traffic and require another order of magnitude more bandwidth

100G will be necessary to cost-effectively satisfy network demands

Advanced modulation formats will allow 100G to have similar reach and ROADM cascadability as 10/40G and to be compatible with 50GHz spacing thus allowing edge upgrade of current and future transparent networks

Photonic Integrated circuits will make 100G transmitters/receiver compatible with los cost, low footprint and high reliability

Optical packet switching may become attractive at 100G to allow for sub-channel connectivity in optical domain

100gbps for nexgen content distribution networks for nexgen content distribution networks martin...

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