ROADM Network Design Issues

48
ROADM Network Design Issues March 23, 2009 NFOEC 2009, Tutorial Sorin Tibuleac Sorin Tibuleac ADVA Optical Networking, Atlanta, GA [email protected] © 2009 OSA/OFC/NFOEC 2009 NMD1.pdf

Transcript of ROADM Network Design Issues

Page 1: ROADM Network Design Issues

ROADM Network Design IssuesMarch 23, 2009,

NFOEC 2009, Tutorial

Sorin TibuleacSorin TibuleacADVA Optical Networking, Atlanta, GA

[email protected]

© 2009 OSA/OFC/NFOEC 2009 NMD1.pdf 

 

Page 2: ROADM Network Design Issues

Outline

Definition features benefitsDefinition, features, benefits

Node configurations

ROADM T h l iROADM Technologies

Transmission impairments

ROADM evolution

ROADM network control

2

Page 3: ROADM Network Design Issues

Definition

ROADM = Reconfigurable Optical Add/Drop Multiplexer

An optical s bs stem capable of selecti e and a tomatic emo al An optical subsystem capable of selective and automatic removal or addition of individual wavelengths from an optical fiber

ROADM

ROADM can also denote a network node

1x9 WSS 9:1 coupler

Transponders

3

Transponders

Page 4: ROADM Network Design Issues

Typical ROADM features

Typically associated with other features

Switching with no impact on other wavelengths

Wavelength monitoring (mostly power)a g o o g ( o y po )

Wavelength power equalization

Network management SW for end to end automated Network management SW for end-to-end automated provisioning

Support for all data rates, modulation formats, protocolspp , , p

Supports external wavelengths

4

Page 5: ROADM Network Design Issues

Benefits

Reduction of OpExSimpler network planning Simpler installation and turn-up of initial systemSimpler installation and turn up of initial systemFaster provisioning and turn-up of new channelsIncreased network availability - avoid manual operations

R d ti f C EReduction of CapExLess OEO regeneration due to power equalizationOptical switching vs. OEO switching with MD-ROADMs

Dynamic provisioning of services

Mesh network protection options

ROADMDemux Mux ROADM

5

Transponders Transponders

Page 6: ROADM Network Design Issues

ROADM Evolution

Mux / Switch / DemuxVOASwitches

Switched (iPLC) VOASwitches

λN

λ1

λN

... ...λ1

1 N1 N Add

1 x N iPLC

Add / DropNN 1 N

DropAdd

Broadcast and Select Switched (WSS)

1 N 1 N

1x1 WSS 1 x N WSS

1 N

. . .

6

1 NDrop

1 NAdd 1

AddN1 N

Drop

Page 7: ROADM Network Design Issues

2-deg. ROADM Node – Fixed λ per port

Transponders iPLC implementation

l dd & O

2 1 WSS1 2 litt

Built-in add mux & OPM

100GHz/40λ

2x1 WSS1:2 splitter

Lowest pass-through loss

T d

Lowest pass through loss

100GHz/40λ and 50GHz/80λ

7

Transponders

Page 8: ROADM Network Design Issues

2 deg. ROADM node - Colorless

1x9 WSS 9:1 coupler

TranspondersCurrently limited to 8 drop ports

Higher loss (mainly from coupler)Transponders Higher loss (mainly from coupler)

Higher cost compared to 2x1 WSS

1x9 WSS 9:1 coupler

h dd l SS’Expansion with additional Nx1 WSS’s

8

Transponders

Page 9: ROADM Network Design Issues

ROADM scalability (deg-2)

Splitter

WSS

XPDR

XPDR

Add/Drop

XPDR

XPDR

Network Interface 1 (Degree 1)

Network Interface 2 (Degree 2)

WSS

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Page 10: ROADM Network Design Issues

ROADM scalability (deg-3)

Splitter

XPDR

XPDR

XPDR

XPDR

WSS

Add/DropNetwork Interface 1

(Degree 1)

Network Interface 2 (Degree 2)

WSS

Network Interface 3 Add/Drop

XPDR

XPDR

Network Interface 3 (Degree 3)

10

Page 11: ROADM Network Design Issues

ROADM scalability (deg-4)

Splitter

XPDR

XPDR

XPDR

XPDR

WSS

Add/DropNetwork Interface 1

(Degree 1)

Network Interface 2 (Degree 2)

WSS

Network Interface 4 Network Interface 3 XPDR

XPDR

(Degree 4)XPDR

XPDR

Network Interface 3 (Degree 3)

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Directionless multi-deg. ROADM node

Additional 9x1 WSS for directionless

Fixed wavelength per transponder Tx/Rx portsFixed wavelength per transponder Tx/Rx ports

Network Interface 1 Network Interface 2

1:N splitter

Nx1 WSS

12

Transponders

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Colorless and directionless MD-ROADM

Network Interface 1 Network Interface 2

1:N splitter

Additional 1xN for colorless

Nx1 WSS

Wavelength blocking

Non-blocking options using

N M WSSNxM WSS

Optical cross-connect with filters, splitters, or 1xN WSS

T d

13

Transponders

Page 14: ROADM Network Design Issues

ROADM Technologies

2-degree MEMS – one axis for switching other for attenuation2-degree MEMS – one axis for switching, other for attenuation

Liquid crystals – stacked for Nx1 WSS

Liquid crystal + 1-degree MEMS – MEMS attenuation LC switchingLiquid crystal + 1-degree MEMS – MEMS attenuation, LC switching

Liquid crystal on Silicon (LCOS) – multiple LC elements per λ

Digital MEMS (DLP array) multiple mirrors per λDigital MEMS (DLP array) – multiple mirrors per λ

Integrated planar lightwave circuits (iPLC) – silica or polymer

Tunable filters (free space optics fiber gratings PLC)Tunable filters (free-space optics, fiber gratings, PLC)

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Page 15: ROADM Network Design Issues

Transmission Impairments

Insertion loss

Bandpass width and shape

Laser wavelength vs. bandpass center offsetLaser wavelength vs. bandpass center offset

Crosstalk and isolation

Att ti d t bilitAttenuation accuracy and stability

PDL

PMD

Chromatic dispersion and phase ripple

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Loss

ROADM loss on express path includes

WSS – across wavelengths, temperature, polarizationWSS across wavelengths, temperature, polarization

Splitter/Coupler

Power ripple from upstream fiber spans/network nodes

Monitoring taps, ageing margin, equalization tolerances…

1x9 WSS 9:1 coupler2 D C l l

8x1 WSS1:8 splitter

2 Deg. Colorless

2x1 WSS1:2 splitter

8 Deg. Colored

16

p

2 Deg. Colored

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ROADM loss in long-Haul networks

ROADM

28

30ROADM 12dB

22

24

26

[dB

]

ROADM 20dB20dB Span

16

18

20

OSN

R [

25dB Span

10

12

14 25dB Span

17

0 2 4 6 8 10 12 14 16 18 20 22 24Number of Spans

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ROADM loss in metro networks

ROADM

30

Lower Loss = Lower cost by eliminating post-amp

22

24

26

28

B]

ROADM 12dB - 1 amp

ROADM 20dB - 2 amps

16

18

20

22

OSN

R [d

B

10

12

14

18

0 2 4 6 8 10 12 14 16 18 20 22 24Number of Spans

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Cascaded PLC ROADMs & Interleavers

ROADM

Passband narrowing and accumulated ripple in recirculating loop with 80λ ROADMs

Individual passbands of 50GHz i t l d 100GH PLC ROADM

Tx Rxin recirculating loop with 80λ ROADMs

Passband shape after 24 ROADMs

-4

-2

Individual passbands of all devices (even)interleavers and 100GHz PLC ROADMs

-4

-2

08x cascade of 6 interleavers (even) and 3 eROADMs(8 loops x3 ROADMs per loop

-12

-10

-8

-6

IL [d

B] PLC

ROADMinterleaver -12

-10

-8

-6

IL [d

B]

-20

-18

-16

-14

-20

-18

-16

-14

19

1530 1530.5 1531 1531.5[nm]

1530 1530.5 1531 1531.5[nm]

Page 20: ROADM Network Design Issues

10G NRZ – 24 ROADMs

10G NRZ not impacted by passband narrowing and accumulated ripple in recirculating loop tests

16

17

)

With ROADMsWithout ROADMs

pp g p

15

16

mea

sure

d) Back-to-back

13

14

Q_e

ff [d

B] (

m

12

13

1525 1530 1535 1540 1545 1550 1555 1560 1565

Q

20

1525 1530 1535 1540 1545 1550 1555 1560 1565Wavelength [nm]

Page 21: ROADM Network Design Issues

10G Metro-Access Lasers

-3

-2

-1

0

40

60

80

100

tance

sion

m]

100GHz PLC ROADM for metro applications

4.010

-9

-8

-7

-6

-5

-4

[dB

]

100

-80

-60

-40

-20

0

20

[ps/

nm]

ROADM 1ROADM 2ROADM 3ROADM 4

Tran

smitt

[dB]

Dis

per

s

[ps/

nm

Wavelength drift of unlocked lasers can generate higher penalties

2.5

3.0

3.5

lty [d

B]

16 ROADMs12 ROADMs8 ROADMs

-10-0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4

[nm]

-100

l i h d b

1.0

1.5

2.0

OSN

R P

enal 8 ROADMs

4 ROADMsPenalties enhanced by

propagation through same devices in recirculating loop

Wid hi h d

0.0

0.5

-0.10 -0.05 0.00 0.05 0.10

Wider, higher-order Gaussian shaped passband required for unlocked lasers

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Wavelength [nm]

S. Tibuleac et al. Asia Pacific Optical Communications Conference 2006

Page 22: ROADM Network Design Issues

Tunable-filter ROADMs

<0.8dB OSNR penalty for 10G, +/-0.15nm drift after 32 devices

No penalty if adjacent λ’s passed throughNo penalty if adjacent λ s passed through

No penalty for 40G NRZ-DPSK after 8 devices (locked lasers)

UNLOCKEDAdd

Express CommonTF-ROADM

LO

CK

ED

TF-ROADM

x6

Tx Rx

22

M. Filer et al. IEEE LEOS Conference 2008

Page 23: ROADM Network Design Issues

40-Gb/s Modulation Format Comparison

ODB/

PSBT

NRZ-ADPSK RZ-ADPSK RZ-DQPSK PM-QPSK

OSNR @ 10-3 [dB] 17.5 13.0 12.5 13.5 12.5

Nominal reach [km] 700 1600 2200 1400 1700

Signal Bandwidth Narrow Medium Wide Narrow Very Narrow

PMD tolerance [ps] 2.5 3.5 3.5 6 3 … 6

Nonlinear sensitivity Medium Low Lowest High High

Complexity / Cost Low Low Low/ Medium High Highest

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Modulation formats with narrow optical spectrum are more sensitive to nonlinear impairments than formats with wide spectrum!

Page 24: ROADM Network Design Issues

40G Modulation Formats

10

Modulation formats for commercial 40G transponders

-10

0

10

m]

-30

-20

10

Bm

/0.0

1n

-50

-40

Pow

er [d

NRZ-DPSKRZ-DPSKCS-RZ

-70

-60

-120 -80 -40 0 40 80 120

CS-RZRZ-DQPSKPSBT

24

-120 -80 -40 0 40 80 120Relative Frequency [GHz]

Page 25: ROADM Network Design Issues

Comparison with ROADM Bandpass

Signal bandwidth clipped by passband of 50GHz WSS

0

nm]

20

-10

dBm

/0.0

1n

-30

-20

Pow

er [d

NRZ-DPSKRZ-DQPSK50 GHz

-40-80 -60 -40 -20 0 20 40 60 80

50 GHz100 GHz

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Relative Frequency [GHz]

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Bandwidth Narrowing

45

40

dth

[GH

z] Measured WSS-50 ROADM Cascade

30

35

dB B

andw

id

4½ Order Gaussian

4th Order Gaussian

25

Ove

rall

3-d

Calculated2nd Order Gaussian

3rd-Order Gaussian

4th-Order Gaussian

201 10 100

N b f C d d ROADM

2nd-Order GaussianTransmission Function

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Number of Cascaded ROADMs

Page 27: ROADM Network Design Issues

Impact of Bandpass Width & Shape

OSNR Penalty at BER 5E-5 after 12 ROADMs

40G DPSK FSR 66GHz

10

]40G DPSK FSR 66GHz

Gaussian Order

6

8

nalty

[dB

]

123

2

4

SNR

Pen

3468

03040506070

3 dB BW f i l ROADM (GH )

OS

27

3-dB BW of single ROADM (GHz)

Page 28: ROADM Network Design Issues

43-Gb/s Transmission over Linear WSS Cascade

OSAOSNRPreset to λ0 = 1555.75 nm (Not Tunable )

43-Gb/s NRZ- / RZ-DPSK Transmitter

TapVar.Atten.

50-GHz WSS # 1

50-GHz WSS # 4

(N)RZ-DPSKAtten.WSS # 1 WSS # 4

50-GHz 50-GHzWSS # 5

1.1-nmFiltTODC

WSS # 8 WSS # 5 Filter

Optical Noise Inserted Midway in WSS Cascade(OSNR Corrected for Filtering in Following WSS’s)

TODC

Delay Δt (OSNR Corrected for Filtering in Following WSS s)

Conventional 43-Gb/s NRZ- / RZ-DPSK Transmitter Balanced Detector with Delay Interferometer for “St ” ADPSK

Delay Δt

Mintera MI 40000

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“Strong” ADPSK,Evaluation Unit

F. Heismann and P. Mamyshev, OFC’09 Paper OThC1

Page 29: ROADM Network Design Issues

OSNR Penalty vs. Optical Bandwidth

19

20

dB] 43-Gb/s Transmission Through Cascaded WSS's

17

18

19

−3 B

ER

[d

Optical

Steep Increase Below 32 GHz

16

17

NR

for

10

pDuobinary

14

15

uire

d O

SN

NRZ ADPSK

RZ-ADPSK

12

13

30323436384042444648505254565860

Req NRZ-ADPSK

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3-dB Bandwidth of WSS CascadeF. Heismann and P. Mamyshev, OFC’09 Paper OThC1

Page 30: ROADM Network Design Issues

Spectrally Dependent Interference

isolationJDSU MWS50

Interfering power is concentrated at edges of signalinterference

isolation

g p gchannel band

Constant Isolation at channel center, rising towards edges

f

signal

interference Interfering power is has components at center and at edges of channel

Spectrally Constant (Coherent)

isolation

signal

interference

Interfering power is concentrated at center of channel

Out-of-Band InterferenceInterfering power has no spectral overlap with

interference

Interfering power has no spectral overlap with signal

30

signal

Page 31: ROADM Network Design Issues

Interference at Channel Center is ~10dB More Damaging

0.8

1

-3) [

dB]

FSO MEMS WSSFlat Isolation Profile WSSIn-Band InterferenceOut-of-Band Interference

0.8

1

0-3) [

dB]

FSO MEMS WSSFlat Isolation Profile WSSIn-Band InterferenceOut-of-Band Interference Ba

nd

t Iso

latio

n

0.4

0.6

nalty

(BER

10- Out-of-Band Interference

0 2

0.4

0.6

enal

ty (B

ER 1

0

Out

-of-B

n-Band

Flat

O MEMS~10dB

-0.2

0

0.2

OSN

R P

e

-0.2

0

0.2

OSN

R P

e In-BFSO M

-10

0

-10

0 FlatI l ti

Interference at Rx -10

0] -10

0]

Interference at Rx

-35 -30 -25 -20 -15 -10 -5Total Interference Power/Total Signal Power at Rx [dB]

-35 -30 -25 -20 -15 -10 -5Total Interference Power/Total Signal Power at Rx [dB]

-50

-40

-30

-20

10

Inte

nsity

[dB

]

-50

-40

-30

-20

10

Inte

nsity

[dB

] Isolationat Rx

-50

-40

-30

-20

10In

tens

ity [d

B]

-50

-40

-30

-20

10In

tens

ity [d

B]

FSO MEMS

at Rx

31

-60-40 -20 0 20 40

Normalized Optical Frequency [GHz]

-60-40 -20 0 20 40

Normalized Optical Frequency [GHz]

-60-40 -20 0 20 40

Normalized Optical Frequency [GHz]

-60-40 -20 0 20 40

Normalized Optical Frequency [GHz]

B. Collings, F. Heismann, C. Reimer, OFC ’09 Paper OThJ3

Page 32: ROADM Network Design Issues

Developments in ROADM subsystems

Improvements in specifications: loss, passband shape, etc

Increased ports (1x20) for colorless ROADM

NxM for colorless and directionless multi-degree ROADM nodes

Integration of optical performance monitoring

Lower-cost WSS or tunable filters for access networks

Integration of new functions: bandpass shaping, dispersion compensation

Si d tiSize reduction

Lower power consumption

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Page 33: ROADM Network Design Issues

NxM WSS for multi-degree ROADM

12x40 MEMS array with integrated drive electronics

MEMS mirrorsMEMS mirrors

IC’s driving i tiltmirror tilt

33

M. Nagy and S. Tibuleac, Photonics Spectra Nov. 2006

Page 34: ROADM Network Design Issues

DRAGON Network Washington DC

5x5 WSS ROADM used in dynamic private network

MIT Haystack ObservatoryU. S. Naval Observatory

University of Maryland Goddard Space Flight Center

CLPKDCGW

DCNE(Q t)

GIG-EF

ARLG

MCLN(Level3)

(Qwest)HOPI

NREN ABILNLR(Level3)

Univ of Southern California/Information Sciences Institute

National Center for Supercomputing Applications

34

S. Tibuleac et al. ECOC 2006, Xi Yang et al. OFC 2006

Page 35: ROADM Network Design Issues

NxM Multicast WSS

4x8 WSS for Colorless and Directionless ROADM

λ1 λ2..... λ43 λ44

λ1 λ2..... λ43 λ44

λ1 λ2..... λ43 λ44

λ1 λ2..... λ43 λ44

N W E SDirectionless ROADM nodes

• Uses splitters, 4x1 l h d

1x8 TSp

1x8 TSp

1x8 TSp

1x8 TSp

N W E S

optical switches, and tunable filters

• Non-blocking

4x1 OSw

4x1 OSw

4x1 OSw

4x1 OSw

4x1 OSw

4x1 OSw

4x1 OSw

4x1 OSw

g

• Flexibility to change port and degree requirements

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

• Port expandable

I2C, RS232, DPRAM

λa λcλb λd λfλe λg λh

35

Customer’s Control Unit

DPRAM

www.enablence.com

Page 36: ROADM Network Design Issues

Kx(NxM) Multicast WSS, Expandable Module

λ1 λ2..... λ43 λ44

λ1 λ2..... λ43 λ44

λ1 λ2..... λ43 λ44

λ1 λ2..... λ43 λ44

• 1st stage, tunable splitter, split ratio can be adjusted freely from switch to splitter function. 44

1xK TSp

1xK TSp

44

1xK TSp

1xK TSp

switch to splitter function.

• setup one 4x8 first for 8 drop ports, then add more drop ports by adjusting split ratio when

1x8 1x8 1x8 1x8 1x8 Sp

1x8 Sp

1x8 Sp

1x8 Sp

1x8 Sp

1x8 Sp

1x8 Sp

1x8 Sp

1x8 Sp

1x8 Sp

1x8 Sp

1x8 Sp

by adjust g sp t at o eneeded.

Sp SpSpSp

4x1 OSw

4x1 OSw

4x1 OSw

4x1 OSw

4x1 OSw

4x1 OSw

4x1 OSw

4x1 OSw

4x1 OSw

4x1 OSw

4x1 OSw

4x1 OSw

4x1 OSw

4x1 OSw

4x1 OSw

4x1 OSw

4x1 OSw

4x1 OSw

4x1 OSw

4x1 OSw

4x1 OSw

4x1 OSw

4x1 OSw

4x1 OSw

1x1 1x1 1x1 1x1 1x1 1x1 1x11x1

4x1 OSw

4x1 OSw

4x1 OSw

4x1 OSw

4x1 OSw

4x1 OSw

4x1 OSw

4x1 OSw

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

1x1 TF

36www.enablence.com

Page 37: ROADM Network Design Issues

Passband shaping

LCOS 2D array with multiple mirrors per wavelength

Control of filter transmission profile

Linear amplitude slopeGaussian functions of different orders

37

Page 38: ROADM Network Design Issues

Programmable dispersion

Dispersion control with LCOS WSS

+/ 80ps/nm for 0 5nm bandwidth+/-80ps/nm for 0.5nm bandwidth

6

-4

[dB

]

6

-4

[dB

]

-10

-8

-6

Inse

rtio

n lo

ss [

-90 ps/nm -10

-8

-6

Inse

rtio

n lo

ss [

90 ps/nm

0

20

p de

lay

[ps]

-70 ps/nm-40 ps/nm-20 ps/nm0 ps/nm

0

20

p de

lay

[ps]

70 ps/nm40 ps/nm20 ps/nm0 ps/nm

1552.8 1552.9 1553 1553.1 1553.2 1553.3 1553.4

-20

Wavelength [nm]

Gro

u

1552.8 1552.9 1553 1553.1 1553.2 1553.3 1553.4

-20

Wavelength [nm]

Gro

up

38

Ref: Roelens et al, JLT 2007

Page 39: ROADM Network Design Issues

Programable Channel Plan on 2x1 WSS

Mixing of 50GHz, 100GHz and 200GHz frequency spacing

Future proof for any conceivable channel modulationp y

Relevant for infrastructure to support future 100 GbE

Programmable continuous spectral shaping

393939

T. Strasser, IEEE LEOS 2008

Page 40: ROADM Network Design Issues

Continuous Programmable Passband

Continuous passband to define channels in software

No filtering impairment transmitting through full passbandg p g g p

High out-of-band attenuation

4040

Page 41: ROADM Network Design Issues

Ultrafast Switching

Microsecond VOA and optical switching with digital MEMS

Improves power control of optical transients Improves power control of optical transients

Enables optical protection switching

VOA ChangeVOA Change

0-15 dB0-1 dB

4141

Page 42: ROADM Network Design Issues

ROADM Challenges for Control Plane

New CapabilitiesD namic choice of add/d op s passth o gh (2 deg ee ROADM)Dynamic choice of add/drop vs. passthrough (2-degree ROADM)Transparent wavelength switching (multi-degree ROADM)Mesh topologies; multiple paths between endpointsOnboard power monitoring, equalization requirementsOnboard power monitoring, equalization requirements

New ConstraintsMany possible ROADM node architectures, with specific quirksROADM “switches” are not orthogonal (continuity requirements, etc)With many possible paths, path selection must be channel-awareUntil tunable filters channel selection still restricted at endpointsUntil tunable filters, channel selection still restricted at endpoints

Result: Management/Control Complexity

42

Page 43: ROADM Network Design Issues

Mesh Topologies

B

A -> D, red

A

Blocked link

B -> C, red

C

Path selection must now consider many more factors

D

43

Page 44: ROADM Network Design Issues

Control Plane Components

Automated Discovery Path Computation Signaling/Provisioning

Topology

How is this network connected?

Capabilities

Path Identification

Which paths are even available?

Path Selection

Element Level

What local equipment must be configured?

Network Level

Fundamental Control Plane technologies applied to reducing

What can this network accomplish?

Which paths meet my service criteria?

Which elements need configuring, in what order?

44

Fundamental Control Plane technologies applied to reducing complexity of managing ROADM networks

Page 45: ROADM Network Design Issues

Power Equalization

End-to-End Service Power EqualizationROADMs include per-wavelength power monitoring, per nodeROADMs include per wavelength power monitoring, per nodeOptical service may traverse multiple ROADM nodes

End-to-end equalization requires adjustments at each node along pathNodes must equalize in sequence, to ensure convergence

Control plane has path, sequence knowledgeSignaling occurs in strict ingress-to-egress sequence

Path computation produces path, signaling follows path

Sequencing used during service provisioningEnables orderly setup, orderly rollback if error occurs

Same sequencing capability useful for power equalizationSame sequencing capability useful for power equalizationEnd-to-end equalization sequence same as initial setup sequenceControl Plane already knows how to follow a path, perform provisioning

45

Control Plane can automate initial end-to-end channel equalization

Page 46: ROADM Network Design Issues

Equalization Process

Path

Path Setup phase (HW at max attenuation) …

[1533.47][1549.32][1549.32] [1533.47]

Resv

[DN EQ] [DN EQ][DN EQ][DN EQ]

… followed by Path Equalize phase (VOAs/ROADMs adjust)

[ Q]

[UP EQ][UP EQ][UP EQ] [UP EQ]

[ Q][ Q][ Q]

Data Flow

46

Page 47: ROADM Network Design Issues

Summary

ROADMs have seen widespread deployments in long-haul and metro DWDM networksmetro DWDM networks

Multiple technology options and node configurations lower network cost and increase flexibility

DWDM network design must account for transmission impairments introduced by each ROADM type

40G transmission through large number of network nodesSignificant improvements in optical specifications of Nx1 WSSImproved understanding of system performance

ROADM technologies offer new features which benefit 40G/100G g /with full flexibility in wavelength routing

Control Plane technologies have adapted to incorporate capabilities of and constraints imposed by ROADM elements

47

p p y

Page 48: ROADM Network Design Issues

Acknowledgments

Mark Filer, ADVA Optical Networking, p g

Wes Doonan, ADVA Optical Networking

Brandon Collings, JDSUg ,

Fred Heismann, JDSU

Tom Strasser, NisticaTom Strasser, Nistica

Simon Poole, Finisar

All colleagues at ADVA Optical NetworkingAll colleagues at ADVA Optical Networking

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