The Transparent Optical NetworkAn Optical Illusion?

An SAIC Company

Richard S. WolffTelcordia Technologiesrwolff@telcordia.com973-829-4537

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Key Contributors

Telcordia: Collaborators-Paul Toliver -GK Chang, Georgia Tech-Matt Goodman -Ben Yoo, UC Davis-Janet Jackel -Dan Blumenthal, UC Santa Barbara-George Clapp-Stu Wagner-Ron Skoog-Haim Kobrinski-Robert Runser-Ann Von Lehmen-Joel Gannett-Brian Meagher

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Outline of Talk

Some background on optical networking Optical packet switching Multi-layer optical network architectures Where do we go from here?

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Growth of the Internet

Nu

mb

er o

f h

osts

, in

mil

lion

s

Source: www.netsizer.com

75% growth in the number of hosts over the last 12 months

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Static

Highly Dynamic

Point-to-PointOptical Transport

Point-to-PointOptical Transport

ReconfigurableOptical NetworksReconfigurable

Optical Networks

Optical LabelSwitching

Optical LabelSwitching

Optical Provisioning, Reconfiguration, and Switching StrategiesN

etw

ork

Eff

icie

nc

y

Present FuturePast

DynamicReconfigurable

Optical Networks

DynamicReconfigurable

Optical Networks

Inflexible reconfigurabilityHigh Management Complexity

Evolution of Optical Networking

True Convergence of IP and Optical Layer

Addresses carrier needs*:• Bandwidth utilization• Provisioning time• Scalability

*RHK Carrier Survey

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WDMWDM WDM

IPIP

WDM

IPWDM

IPIP

WDM

IPWDM WDM

IPIP

WDM

IP

WDM

IP IPIP

WDM

IPWDM WDM

IPIP

WDM

IP

WDM

IP IPIP

(b)

(c)

(a)

IP and Optical RoutingIP over Re-configurable WDM Packet Routing Strategies:(a) IP/Client Layer, (b) MPS/Integrated Layer, and (c) OLS/Transport Layer

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Key Enabling OLS Technology

Optical Header Extraction Unit

High Bit RateOptical Packet

Low Bit RateSubcarrier Label

Label Extractedfor Processing

Label and PacketForwarded

to Forwarding Engine

Fiber

Only low cost electronics required to

process the label in parallel

Frequency

NRZ PacketPayload Subcarrier

Optical Label

Packet payload and in-band OLS label are decoupled through the use of subcarrier multiplexing technology

The simplified packet processing hardware results in significant cost savings for core network interfaces

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Sub-carrier Receiver

Header Processor

Forward Engine

SwitchControl

Logic

Sub-carrier Receiver

Header Processor

Forward Engine

LiNbO3 Optical Switch

Fiber DelayLine

Optical-Label Switch Node Design

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Forwarding engine

OLSSwitch Fabric

Routing protocols

IncomingOpticalTraffic

Beta Client Specified Interface

Optical HeaderExtraction

Switch Drivers

Control

plane

OutgoingOpticalTraffic

N ’sper fiber

N labels

NC

&M

NC&M

GbEPOS

OC-X

Optical Label Switch Router- Schematics

Interoperable with existing

network elements

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Optical Label Switch Router–Physical Layout

Workstation

OLS Receiver array

Tranport Interface

OLS Switch Control Plane

Fiber Amplifiers

1 2 3 4

CH. 1 CH. 2 CH. 3 CH. 41 2 3 4

1 2 3 4

1 2 3 4

VideoKM

Running OLS Server....128.96.80.230

Edgenode

Corenode

OLS system processorGbE NIC

OLS transmitterOLS receiver

Optical header generator

Optical switch fabric &packet forwarding engine

Optical header receivers

Client/transport interface

Optical amplification,wavelength conversion

Craftinterface

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Optical Switch Fabric and Forwarding Engine

LiNbO3

switch driver

Network control

processor

Optical switch ribbon input

Optical switch ribbon output

LiNbO3

switch array

PacketForwarding

engine

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Switch Fabric Testing: Optical Rise & Fall Time

0.0

0.2

0.4

0.6

0.8

1.0

0 2 4 6 8 10 12 14 16 18 20

Time (ns)

Op

tica

l o

utp

ut

(A.U

.)Optical rise & fall time: ~3 nsDead time: ~6 nsTotal packet guard time: <10 ns

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Optical Label Switching NGI Testbed Laboratory

1

2

4Tx Rx Tx Rx

Tx RxTx Rx

3

Switch node

Terminal

NC&M

NC&M Interface

Host 4

Host 2

Host 3

Host 1

EdgeRouters

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Areas for Research: Label Swapping and Wavelength Conversion

Wide tunable semiconductor lasers– Tuning range: 40nm– Frequency accuracy: <10GHz– Accessing speed: < 10ns

Wavelength converter– Any wavelength to a fixed wavelength– Any wavelength to any wavelength– Efficient fiber couple with expanded beam technologies

Subcarrier Label Swapping– Optical notch filter in combination with single side band SCM

tramsimitter (Improved tracking mechanism) by NCTU– Semiconductor optical amplifier (SOA) based optical label

eraser as a low-pass filter by UCSB

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Area for Research: Optical Switch Fabric Technologies

LiNbO3 Waveguide Switch (Lucent, EOspace, Lynx)– PDL, < 1dB– High crosstalk rejection, >35 dB– Fast switching, 5 ns– Medium dimension, 16 x 16

SOA Optical Switch (Alcatel, NEC, Kamelian)– Fast Switching, 1 ns– Provide optical dump– Optical multicast– Small dimension with PIC technology, 4 x 4

3-D Optical MEMs (Lucent, Calient, Nortel)– Low insertion loss– Large dimension, 256 x 256 – Switching speed, currently 10 ms

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Areas for Research: Network Issues

Critical Issue : Absence of Optical Buffer Memory

Lack of Precision Optical Synchronization

Contention of packets at the switching nodes

Possible Solutions :– Wavelength Conversion– Deflection Routing– Wavelength Flooding– Deflection Flooding

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Optical-Label Switching for Packet Routing

• Priority• Wavelength interchange• Alternate path

t

DATAOpticalHEADER

SignalSource

SignalDestination

Optical-label switching

IP/WDM Node

alte

rnat

e p

ath

alternate wavelength

preferred path

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Simulation of OLS Packet Dropping

OLS Drop Rates for Various Wavelength Counts

1.00E-13

1.00E-11

1.00E-09

1.00E-07

1.00E-05

1.00E-03

1.00E-010.05 0.15 0.25 0.35 0.45 0.55 0.65 0.75 0.85 0.95

util ization

dro

p r

ate

8:OLS16:OLS32:OLS

64:OLS128:OLS

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The Multi-layer Transparent Optical Network

Objective:

To provide a scalable multi-granular photonic layer infrastructure with the ability to provide intelligent dynamic access into optical bandwidth from packet to pipe.

the optical layer IS the convergence layer… Multi-granularity Multi-protocol capable Multi-format/bit-rate support Multi-domain support: wireless & wireline Multi-vendor, multi-technology interoperability

designed in

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Waveband granularity

Wavelengthgranularity

Fibergranularity

Vision of a Multi-layer Optical Network

Optical packet/burst granularity

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Multi-layer Optical Network Requirements

Optical granularitylevel

Typical bandwidthrequirements

Typical switch reconfiguration timerequirements

Optical packet 10 Mb/s-10Gb/s 10 ns-10 s

Optical burst 1Gb/s-10Gb/s 1 s-100 ms

Wavelength 2.5 Gb/s-40Gb/s 10 ms-500 ms

Waveband 10 Gb/s-640Gb/s 100 ms-10 s

Fiber 80Gb/s-6.4Tb/s 1 s-100 s

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Edge-to-Edge Flows:Transparency selected to meet application requirements

… … … …

Fiberband

OPS

IP

Fiberband

OPS

IP

Fib

erb

and

OP

SIP

Fib

erb

and

OP

SIP

Fib

erb

and

OP

SIP

Fib

erb

and

OP

SIP

Fiberband

OPS

IP

Fiberband

OPS

IP

Fiberband

OPS

IP

Fiberband

OPS

IP

… … … …

Fiberband

OPS

IP

Fiberband

OPS

IP

Fib

erb

and

OP

SIP

Fib

erb

and

OP

SIP

Fib

erb

and

OP

SIP

Fib

erb

and

OP

S

Fiberband

OPS

IP

Fiberband

OPS

IP

Fiberband

OPS

IP

Fiberband

OPS

IP

IP

• = wavelength

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ATDNet: An Experimental Transparent Optical Network

DIANRL

NASA

DISA

DARPA

LiNbO3 WSXC

LiNbO3 OADM

OEO OADM

MEMS OXC

LTS

EDFA

Client WDM fiber

WestRing East

Ring

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Optical WDM Wavebanding Approaches

Contiguouswavebands

l

l

Interleavedwavebands

Arbitraryreconfigurable

wavebands

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Experimental Demonstration of Wavebanding

ATDNet West Ring25 GHz

200 GHzpassband

Add

Drop

Waveband

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Optical Burst Transmission Exeriment

ATDNet, LTS-NRL-LTS

40 50 60 70 80 90 100

Am

plit

ud

e (m

W)

15% Duty Cycle170 sec period

26 sec burst

40 50 60 70 80 90 100Time (sec)

Am

plit

ud

e (m

W)

70% Duty Cycle170 sec period

120 sec burst

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Optical

Section

Optical

Section

OpticalOptical OpticalOptical

Monitoring in Transparent Networks

OE boundaries within service provider administrative domains may completely disappear

Path

Line

Section

Line

ADMs &DCS

Regenerator

O/E/O

Section

Line

Section

ADMs &DCS

Regenerator

O/E/OPath

Line

Section

Administrative BoundaryCPE CPE

Optical Optical

EDFAEDFA

Optical Optical

Customer

Specified

Service

Customer

Specified

Service

Routers &Switches

Routers &Switches

OpticalOptical

OADMs & PXCs

OADMs & PXCs

Optical Performance Monitoring (OPM) required

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What is Needed - Areas for Research

Architecture– Dynamic network reconfiguration in response to changing

traffic demands Enabling Technologies

– Multi-granular, high performance, scalable optical switch fabrics

– Wavelength agility and conversion– Optical packet switching technologies from switches to

receivers Network Management

– Unified management of multi-granularity transport and switching

– Policy management of configurations, services, security– Favorable compromise combining peer-to-peer and

centralized management– Automated traffic engineering and connection management

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The Transparent Optical NetworkWill packets and fiber optics converge?

Fiber Optics Packet Networks

?