turbo: terabits/s using reconfigurable bandwidth optics · pdf fileocs roadm roadm roadm...

LIGHTWAVE RESEARCH LABORATORYC O L U M B I A U N I V E R S I T Y

TURBO: Terabits/s Using Reconfigurable

Bandwidth Optics

Dan Kilper, Madeleine Glick UA

Keren Bergman Columbia University

February 18, 2016


Adding Airlines to Google Maps

2


TURBO Concept

• Develop SDN control methods to establish end to end intra domain flexible optical spectrum paths• Layer 2 inter-domain connections

• Develop transparent cross-domain handover methods

• Create optical physical layer orchestrator

Long Haul

ROADMOA

OA

ROADM

OA

ROADM

ROADMROADMROADM

OTN/Eth

OPL-O

OTN/Eth OTN/EthOTN/Eth

MetroCampus A

OTN/Eth

OTN/Eth

ROADMROADM

OCS

OTN/Eth OTN/Eth

OTN/Eth

OCS

OTN/Eth

Data Center

Metro Campus B

ROADMROADM

OTN/EthOTN/Eth

Layer 2 Handover

Transparent Handover

Intra-Domain End-to-End Transparent

OPL-OOPL-O

OPL-O

OPL-OOPL-O


Team

•University of Arizona• D. Kilper

• M. Glick

• Transparent Optical Aggregation Networks Testbed• 30 Gbaud coherent modulation

• Mesh network emulation platform

• Columbia University• K. Bergman

• Lightwave Research Lab• Inter-data center testbed

• CIAN: Center for Integrated Access Networks• NSF ERC, 18 Industry members, 8

Universities

4

Arizona TOAN Lab

Columbia LRL Data Center Testbed


Lightpath Configuration Time

5

DICONET Project, Angelou, et. al. IEEE Comm Mag. 2012

Does not include physical device control and tuning delays from physical setup

Computation, signaling, and protocol part: ~ 1 second CORONET: 700ms


Optical Switches, but no optical switching networks

Infinera record:

8 Tb/s provisioned in 19 minutes

•16 channels

•Over pre-determined path Amsterdam to Hamburg

“Optical burst switch developer Intune Networks in receivership” – LightwaveMag.

6www.guinessworldrecords.com


ON Lab, AT&T: Want White Box Programmable ROADMs

7


Optical Power Dynamics: Unsolved

•Network problem not an amplifier problem• Present even for perfect constant gain control

•Only a problem for optical transmission with real-time wavelength switching•Power dynamics, similar to noise performance,

polarization effects, nonlinear impairments, must be addressed and lead to a trade off between cost and performance•Higher performance (less dynamics) leads to higher

cost• Better/more components• Better/more complex control algorithms


Optical Transients: Solved Problem

• Single EDFA problem

• Fast Feedforward Control & Nonlinear Feedback

9Tian & Kinoshita, JLT 2003

No Feedforward With Fast Feedforward


10

Optical Power Dynamics

F. Smyth, et. al. JLT 2009


TURBO Goals

• Realize a white box optical transmission system control system• Only proprietary today• Allow researchers to program new algorithms and investigate new

abstractions

• Realize a programmable and transparent SDX

• Demonstrate end to end intra- and inter-domain flex grid transparent path creation using these new capabilities

• In each case these are v1.0 implementations to open the door for further development and promote opening up of transmission systems

11


TURBO Impact•Bring optical transmission system (ROADM) control

into research domain• Don’t expect commercial systems to ever be entirely open,

but this approach enables experimentation of where that line should be drawn

•Enables White Box ROADMs, Disaggregated ROADMs, etc.• Stimulate new area of research• Promote creation of SDN interfaces in optical elements

• Enable demonstrations (ON Lab) to include optical trans.• Encourage system vendors to open up their products to more

programmability

12


Scheduler

Cross-Domain Interface

Policy Manager

Network State/ Abstraction

Ntwk State/ Abstraction

DataCenterSDNos

OPL Controller

MetroSDNos

WAN Network OS

Control Data Translator

DPCE

DPCE

OPL Orchestrator

ROADMOA OA

ROADMOA

ROADMROADMROADMOCS

OTN/Eth

Layer 2 Controller

Layer 2 CntrlOPL

Orchestrator

OTN/Eth OTN/Eth

Layer 2 Controller

OPL Orchestrator

OTN/Eth

Domain 2 Domain 3Domain 1

OPL-O: Optical Physical Layer Orchestrator

13

SENSE, BDESDNos, Network OS

OpenFlow, Proprietary, TL1


Role of OPL Orchestrator

•Control diverse set of optical transmission hardware to operate network• Provision channels• Tune amplifiers• Tune channel powers• Manage faults, e.g. node loss, transient recovery• Defragmentation• Real time route selection*• Real time elastic bandwidth/flex grid

management*• Wavelength layer protection • ….

14

Future

Current propriety solution


Worst Case Power Excursion: Remove 1 Chn

15

5 10 15 20-16

-14

-12

-10

-8

-6

-4

-2

0

ROADM Node Hops

Po

we

r E

xcu

rsio

n (

dB

)

2 4 6 8 10 1210

-1

100

101

102

103

De

lay (

s)

ROADM Node Hops

1dB

6dB

3dB

tn=10 s

tn=5 s

tn=1 s

tn=0.1 s

Peak to Peak Ripple

Consider accumulated ripple between ROADM nodes: 3-4 dBChannels flattened at each ROADM in steady state


Delay Accumulation with Node Hops

16

5 10 15 20-16

-14

-12

-10

-8

-6

-4

-2

0

ROADM Node Hops

Po

we

r E

xcu

rsio

n (

dB

)

2 4 6 8 10 1210

-1

100

101

102

103

De

lay (

s)

ROADM Node Hops

1dB

6dB

3dB

tn=10 s

tn=5 s

tn=1 s

tn=0.1 s

te=2tn, DPref = 1 dB, 3 dB ripple


• Open channel and bring up/down slowly

Wavelength Switching: Step by Step

ROADM1 OA ROADM2 ROADM3OA

Decreasing power on 1535 nm Increasing power on 1560 nm

Power (dBm)

-25

-2

6-2

7-2

8-2

9-3

0-3

1-3

1

-33

-32

-31

-30

-29

-28

-27

-26

-2

5

-24

-2

3

-22

-2

1-2

0

-24

-24

-23

-22

-21

-20

-19

-19

No

λ-32

-33

-190

0.2

0.4

0.6

0

Sati

c ch

ann

el

Excu

rsio

n (

dB

)

**

* WSS adjustment to negate excursion

*


• Switch laser faster than EDFA response time

• Vary dwell time on each wavelength

• Full power at all times

• Reduce number of steps

Wavelength Switching: Fast Tunable Laser

10

0%

95

%

90

%

80

%

70

%

50

%

40

%

30

%

20

%

10

%

60

%

5%

1535nm dwell time %

0%

0

0.2

0.4

0.6

0

Stat

ic C

han

nel

Ex

curs

ion

(d

B)

50

%

20

%

0%

0%

5%

10

%

20

%

30

%

50

%

60

%

70

%

80

%

90

%

40

%

95

%

10

0%

50

%

80

%

10

0%

1560nm dwell time %

**

WSS adjustment

*

*


SDN Control Plane

19

R1 OA OA R9R2 R7R3 R4 R5 R6 R8 R10

Z. Wang JLT 2014

Parallel and independent ROADM node control

9 dB!

Scheduler


Policy Manager



OPL Controller

WAN Network OS


DPCE

DPCE

OPL Orchestrator


Factors that Impact Power Dynamics

•Order and timing of node adjustments

•Node control algorithm

•Channel loading and configuration

•Timing of wavelength switching

•Wavelength Route Characteristics

20


SDN Control Plane

21

R1 OA OA R9R2 R7R3 R4 R5 R6 R8 R10

Z. Wang JLT 2014

Parallel Modified ROADM node control

<2.5 dB!

Scheduler


Policy Manager



OPL Controller

WAN Network OS


DPCE

DPCE

OPL Orchestrator


Appropriate Abstractions for OPL?

WSS OA WSSTx/Rx

Tx/Rx

… Tx/Rx

Tx/Rx

...

• Layer 2/Ethernet switch: details are hidden, complexity goes to OPL• Problem: Only works for small networks, large margins• Problem: wavelength blocking, reach and power dynamics

• Network Models: a network of five nodes with multiple ports• Stable reconfiguration using OPL orchestrators for each domain• Colored ports: BW, latency, setup time, osnr, …

D2

D1

D4

D3

D5

N1N3

N4N5

N2


OPL Orchestrator

• Dynamic PCE• Rules and logic for spectrum assignment and path selection

• Abstraction Model• Representations of available spectrum and paths throughout network

• Cross-Domain Interface• What spectral information gets shared?

• How to represent path dependent spectral information between domains?

• OPL Controller• Implements flexgrid assignments across

many nodes and switches• Tuning of WSS controls

• What happens when a filter encroaches on a live signal to allow room for a new signal?

Scheduler


Policy Manager



OPL Controller

WAN Network OS


DPCE

DPCE

OPL Orchestrator


Optical Flexigrid

• Fixed grid: assign wavelengths to rigid spectral slots or channels

• Flex grid: wavelengths can be assigned to an arbitrary spectral location and allocated different spectral widths • Channel widths can be variable

• Spatial dimentions (multi-fiber, multicore) can also be used

• Flexgrid capabilities have unique operational and control characteristics

• Spectrum may become fragmented

A B C D

unused spectrum

contiguous spectrum block

spectru

m

spectrum continuity constraint


Multi-Hop Spectrum Continuity

A B C D

500k0x200G

unused spectrum

contiguous spectrum block

spectru

m

Filter

500k1x50G

1x filtered spectrum block

signal spectrum

• Spectrum is not all or nothing

• Wide passbands for filter cascades & spectral broadening• Varying filtering conditions can be managed along path• Need to manage crosstalk

• How to manage used BC spectrum that overlaps ABCD assignment?


Cross-Domain Abstractions

• Performance weights for available routes

• Investigate defragmentation policies for common cross

domain spectrum

• DPCE: Flex grid performance constraints with IA-RWA

• Use AOPM at boundaries

AB

Scheduler Policy: Reserve Shortest

Domain State/ Abstraction

Domain 1 Orchestrator Inter-Domain Protocol & AbstractionCross-

Domain Interface

Domain 2 Orchestrator

Domain 1 Abstraction

Domain 2

6

9

6

3

2

2

104

9

free spectrum

Domain 1 OPL Orchestrator

SchedulerPolicy: Reserve Shortest

Domain State/ Abstraction

Cross-Domain

Interface

Domain 2 OPL Orchestrator

10, 9

2

6

BA

A B

Domain 1

Domain 2 Abstraction


Transparent Domain Boundary

•How to achieve spectrum continuity across domains?

•Need guarantees for SLAs• Who’s to blame if something goes wrong

Long Haul

ROADMOA

OA

ROADM

OA

ROADM

ROADMROADMROADM

OTN/Eth

OPL-O

OTN/Eth OTN/EthOTN/Eth

MetroCampus A

OTN/Eth

OTN/Eth

ROADMROADM

OCS

OTN/Eth OTN/Eth

OTN/Eth

OCS

OTN/Eth

Data Center

Metro Campus B

ROADMROADM

OTN/EthOTN/Eth

Layer 2 Handover

Transparent Handover

Intra-Domain End-to-End Transparent

OPL-OOPL-O

OPL-O

OPL-OOPL-O


Dual Layer SDX Handover

•SLA based on advanced Optical Performance Monitoring (AOPM)

•Flexgrid WSS: enforce spectrum continuity

AOPM

OTN/Eth

FWSS

FWSS

FTL

CT

OTN/Eth

AOPM

FOPC FOPC

FWSS

FTL

CT

OpaqueGateway

TransparentGateway

OPL Orchestrator


Transparent SLAs

• Use spectrum continuity and guardbands as specification

• Use OSNR for performance guarantee• Key performance parameter for

coherent

• Silicon photonic OSNR monitor• Coherent

• Polarizaiton Independent

• Modulation Calibrated

29

Chip Scale OSNR Monitor


Network Transmission Emulation

• Introduce multiple impairments to reproduce range of phenomena

30

PDL

VOA

POL Filter

ROADM

ROADM

ROADMROADM

ASE

High Power

Large Ripple


Distance Emulation

31


TURBO DeliverablesYear 1

• Define use cases

• Optical physical layer orchestrator implemented in testbed

• Prototype of transparent SDX

Year 2

• Optical physical layer abstraction models for single domain control

• Optical physical layer control algorithms for single domain, performance with SDN

• Multi-domain transparent path establishment

Year 3

• Physical layer abstraction models for multi-domain control

• Experiments on dynamic real-time provisioning of optical connections across multiple network domains in the emulated optical networking platform

32


Roles and Responsibilities

•UA• Path setup and control (OPL Controller)• Flexgrid Optical transmission, inter- and intra- domain• Transparent SDX• OPL abstraction

•Columbia• SDN Implementation and interface to network OS• Wavelength resource management/rwa: DPCE

33


Looking forward 10 years

34

Space Switch

Coupler #1

...

Coupler #k

...

...

Demux #1

...

Demux #k

...

AWG#1

...

... ...

...

...drop

add

fibers

...AWG#s

...

...

E-Switch#1

...

...

E-Switch#t

...

... ...

...

Space Switch

...

Millisecond Switching

Microsecond Switching

Millisecond WAN WDM Switching

Data center/hpc server racks

Data center/hpc server racks

Millisecond Switching

TOR

TOR

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