1AC_054_2000 © 2000, Cisco Systems, Inc.

Intelligent Optical NetworksIntelligent Optical Networks

Axel ClaubergConsulting Engineer

Cisco Systems Axel.Clauberg@cisco.com

Axel ClaubergConsulting Engineer

Cisco Systems Axel.Clauberg@cisco.com

2AC_054_2000 © 2000, Cisco Systems, Inc.

AgendaAgenda

• The Need for Optical Networks

• Dense Wavelength Division Multiplexing (DWDM) Overview

Basics

Fibers & Physics

Long Haul, Metro WDM

DWDM Junctions

• Wavelength Routing – MPS

3AC_054_2000 © 2000, Cisco Systems, Inc.

The Need for The Need for Optical NetworksOptical Networks

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Driving FactorsDriving Factors

• Exponential IP traffic growth

ISPs: Factor 2 - 8 growth per year

...sometimes only throttled by congested US links...

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Driving Factors Driving Factors R&D/EDUR&D/EDU

• Distance and Lifelong Learning

• High resolution, studio quality video

Telemedicine

• Digital Libraries

• High performance distributed computing

• More to come…

6AC_054_2000 © 2000, Cisco Systems, Inc.

Driving Factors - SPsDriving Factors - SPs

• Increasing number of users

• Higher bandwidth per user

DSL, Cable, Fiber to the Home, ...

• Storage Networks

• Reduce costs for infrastructure and operations

• React fast(er than the competition)

• High availability

7AC_054_2000 © 2000, Cisco Systems, Inc.

New Currency UnitNew Currency Unit

• Old WAN bandwidth currency units

E1 ( 2 Mb/s)

E3 (34 Mb/s)

STM-1 (155 Mb/s), FE (100 Mb/s)

STM-4 (622 Mb/s), GE (1000 Mb/s)

• Today: STM-16 (2.5 Gb/s)

• Tomorrow: STM-64, 10GE (10 Gb/s)

8AC_054_2000 © 2000, Cisco Systems, Inc.

Current Current Carrier Carrier Situation - SDHSituation - SDH

Ring A

Ring B

Ring C

• Connect Routers via E1, E3, STM-1 or STM-4

• Provision Local ADMs (VC-12, VC-3, VC-4, VC-4c)

• Provision Intermediate ADMs and Crossconnects

10AC_054_2000 © 2000, Cisco Systems, Inc.

SDH DrawbacksSDH Drawbacks

• No STM-16c customer/tributary SDH interfaces today

SDH just made the step to STM-64 in the backbone

• Provisioning in SDH PVC-like („static routing“)

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Global Optical Networks MarketsGlobal Optical Networks Markets1999-20041999-2004

Source : Pioneer 1999

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DWDM OverviewDWDM Overview

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WDM ApplicationsWDM Applications

Long Haul WDMLong Haul WDM

Metro WDMMetro WDM

CampusCampusWDMWDM

1995 2000 2005

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Enterprise Optical NetworkingEnterprise Optical Networking

STM-4cSTM-16c

AggregationAggregation

E3

STM1

FE, GEFDDI

ATM/SDH, DPT

Data & StorageData & Storage

ESCONFICONFiber Channel

15AC_054_2000 © 2000, Cisco Systems, Inc.

WavelengthConverter

WavelengthConverter

Passive OpticalMuliplexer

1300 nm

1300 nm

WavelengthConverter

850 nm

Ch 1

Ch 2

Ch n

Ch 1

Ch 2

Ch n

WDM System TransmitterWDM System Transmitter

16AC_054_2000 © 2000, Cisco Systems, Inc.

WavelengthConverter

WavelengthConverter

WavelengthConverter

WavelengthConverter

WavelengthConverter

WavelengthConverter

WavelengthConverter

WavelengthConverter

WavelengthConverter

WavelengthConverter

WavelengthConverter

WavelengthConverter

Ch 1

Ch 2

Ch n

1

2

n

Mux &Demux

Mux &Demux

Mux &Demux

Mux &Demux

1

2

n

WDM System FunctionWDM System Function

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WDM HistoryWDM History

• First 2 wavelength () systems in the early 90s: 1300 nm, 1550 nm

• More wavelengths with 400 GHz spacing within 1550nm window in mid 90s

• Today up to 128 wavelengths (50 GHz, 100 GHz Spacing)

• = c / f (c = speed of light, f = frequency)

18AC_054_2000 © 2000, Cisco Systems, Inc.

DWDM Frequencies DWDM Frequencies

In the (1529-1536) nm region called BLUE BAND (C), • 8 channels 100 GHz spaced

• 16 channels 50 GHz spaced can be multiplexed

In the (1542-1561) nm region called RED BAND (C) ,• 24 channels 100 GHz spaced

• 48 channels 50 GHz spaced can be multiplexed

In the (1575-1602) nm region called INFRA-RED BAND (L),• 32 channels 100 GHz spaced

• 64 channels 50 GHz spaced can be multiplexed

1530 nm 1540 nm 1550 nm 1560 nm 1570 nm 1580 nm 1590 nm 1600 nm

BLUE BAND RED BAND INFRA-RED BAND

Conventional Band (C) Long Band (L)

19AC_054_2000 © 2000, Cisco Systems, Inc.

Attenuation: Reduces power level with distance

Dispersion and Nonlinearities: Erodes clarity with distance and speed

Signal detection and recovery is an analog problem

Analog Transmission EffectsAnalog Transmission Effects

20AC_054_2000 © 2000, Cisco Systems, Inc.

Fiber AttenuationFiber Attenuation

Wavelength (nm)

~ 200 ppb OH

OHPeaks

“FirstWindow”

“Third”“Second”

Rayleighscattering

1

4( )

Attenuation

db

Km[ ] Infra-redAbsorbtion

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PUMPED ENERGY PHOTON

980 nm

TRANSITION

METASTABLE STATE

SIGNAL PHOTON

PASSIVE

STIMULATED PHOTON

Optical Amplifiers:Optical Amplifiers:PrinciplePrinciple

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Optical Transmission:Optical Transmission:Chromatic DispersionChromatic Dispersion

• Different colors of light travel at different speeds

• Spectral broadening caused by differential group delay

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Chromatic Dispersion (CD)Chromatic Dispersion (CD)

1) Effect and consequences

• The refractive index has a wavelength dependent factor, wavelengths are not travelling at the same speed (the higher frequencies travel faster than the lower frequencies)

• The resulting effect is a broadening of the signal and a consequent interference

2) Counteractions

• use of TDM rates <= 2.5 Gb/s; electrical regeneration; dispersion compensation, use of DS or NZDS fibres, use of soliton transmission

t t

t t

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-20

-15

-10

-5

0

5

10

15

20

25

1350 1370 1390 1410 1430 1450 1470 1490 1510 1530 1550 1570 1590 1610 1630 1650

DSG.653

NZD+ NZD- SMFG.652

Dispersion SlopesDispersion SlopesD

isp

ersi

on

(in

ps/

nm

/km

)

Wavelength (in nm)

DWDM bandG.655

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4-Wave Mixing (4WM)4-Wave Mixing (4WM)

1) Effect and consequences

• Generation of new optical waves (mixing products) due to the interaction of the transmitted optical waves, the mixing products interfere with the transmitted channels causing consequent eye closing and BER degradation.

• Channel spacing and chromatic dispersion affect the FWM.

2) Counteractions

• use of G.652, G.655 fibres; adopt a unequal channel spacing for preventing the mixing products to interfere with the transmitted channels

fijk - fi = fj - fk (i,j <> k)

1 2 3

f113 f112

f123

f213

f223 f132

f312

f221 f332

f321

f231

f331

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Non Linear Effects:Non Linear Effects:FWM continued...FWM continued...

f1 f2 f3

Pow

er (

a.u.

)

Frequency

f f

9 FWM products generated, 3 fall on signal channels

f113

f112

f123

f223

f132

f221

f332

f231

f331

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Non Linear Effects:Non Linear Effects:FWM continued...FWM continued...

f1 f2 f3

Pow

er (

a.u.

)

Frequency

f f

f113 f112 f331

f231f332

f221

f223

f132f123

9 FWM products generated, none fall on signal channels

28AC_054_2000 © 2000, Cisco Systems, Inc.

Long Haul vs. Metro DWDM

Fundamental Differencies

• Long Haul: Carrier Class, SDH Framing, OA, Size, Tuning Capabilities, 128 channels

• Metro: Cost effective, Bitrate transparent, no OA, 32 channels

29AC_054_2000 © 2000, Cisco Systems, Inc.

WDM TopologiesWDM Topologies

Point to Point

Add and Drop

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Case Study - A European Service Provider

Problem: E2E Provisioning, Protection

• Lots of interconnected DWDM structures

Helsinki

Madrid

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4

1

Today’s DWDM JunctionsToday’s DWDM Junctions

2

5 63

!!• Static Lightpath (LP)

Configuration

Long Provisioning TimeHigh Operational Costs

• Installing new LP is potential Risk to cut another LP

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Wavelength RoutingWavelength Routing

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Wavelength Routing makes Wavelength Routing makes DWDM Junctions ScaleDWDM Junctions Scale

1

3

2

12

4

3

4

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DWDM Junction EvolutionDWDM Junction Evolution

Innovation

Time

• Fiber Patch Panel

• Wavelength Router running an Optical Routing Protocol

• Wavelength Router with an integrated optical solution

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A Wavelength Routing A Wavelength Routing Network is ...Network is ...

. . . a Mesh of Optical Transmission and Switching Equipment

P-t-P DWDM System

Optical Cross Connect (OXC)

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. . . , which provides dynamic Point-to-Point Connections

SONET/SDH, Gigabit Ethernet,

A Wavelength Routing A Wavelength Routing Network is ...Network is ...

A Wavelength Routing A Wavelength Routing Network is ...Network is ...

SONET/SDH

Gigabit Ethernet

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. . . to attached Internetworking Devices.

IP Routers, SONET/SDH Muxes, ATM Switches, ...

A Wavelength Routing A Wavelength Routing Network is ...Network is ...

A Wavelength Routing A Wavelength Routing Network is ...Network is ...

SDH Mux

Black Box

IP Router

?

?

?

38AC_054_2000 © 2000, Cisco Systems, Inc.

The Key Element is the The Key Element is the Wavelength RouterWavelength Router

Wavelength Router

Control Plane:Wavelength Routing

Intelligence

Data Plane:Optical Cross

Connect Matrix

Single Channel Links to IP Routers, SDH

Muxes, ...

Unidirectional DWDM Links to

other Wavelength Routers

Unidirectional DWDM Links to

other Wavelength Routers

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Data PlaneData PlaneFirst Generation Wavelength RouterFirst Generation Wavelength Router

Cross-Connect

1

3Hybrid OXC: O/E Conversion, Switching, E/O ConversionPure OXC: Wavelength Conversion

Outgoing InterfaceIncoming Interface

Animated

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Data PlaneData PlaneWavelength Router with integrated DWDMWavelength Router with integrated DWDM

Cross-Connect

1

3Hybrid OXC: O/E Conversion, Switching, E/O ConversionPure OCX: Wavelength Conversion

Outgoing InterfaceOutgoing Wavelength

Incoming InterfaceIncoming Wavelength

41AC_054_2000 © 2000, Cisco Systems, Inc.

Control PlaneControl PlaneWavelength Routing IntelligenceWavelength Routing Intelligence

• Resource Discovery

• Topology State Maintenance

Reliable broadcast

• Path Selection

Constraint-based Routing

• Optical Channel Management

Path placement

Path maintenance Path revocation

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ATM

MPLSIP-LSR

OXC

Method StandardBody Routing Signaling Available

None

ATMForum

IETF

Proprietary

PNNI

Constraint-based

PNNI

LDP / RSVP

Trials

Deployed

Deployed

Proprietary

Source: John Drake -- MPLS Conference 1999Source: John Drake -- MPLS Conference 1999

Existing Control PlanesExisting Control Planes

43AC_054_2000 © 2000, Cisco Systems, Inc.

ATM

MPLSIP-LSR

OXC

Method StandardBody Routing Signaling Available

IETF

IETF

IETF

Constraint-based

Constraint-based

Constraint-based

MPLS-TE

MPLS-TE

Future

Trials/Deployed

Deployed

MPLS-TE

Source: John Drake -- MPLS Conference 1999Source: John Drake -- MPLS Conference 1999

Uniform Control Plane ParadigmUniform Control Plane Paradigm

44AC_054_2000 © 2000, Cisco Systems, Inc.

• Original rational—integrate:

Layer 3 routing—scalability and flexibility

Layer 2 switching—high-performance and traffic management

• Now architecture for new services…

++ ==

What we already did with IP+ATMWhat we already did with IP+ATM

ATM-LSR*IP-LSR*

* LSR . . . Label Switch Router

45AC_054_2000 © 2000, Cisco Systems, Inc.

LSR and OXC SimilaritiesLSR and OXC Similarities

• Data vs. Control planes

they both clearly distinguish these planes

• Data plane driven by a switching matrix

LSR: (i_if, ingress label) => (o_if, egress label)

OXC: (i_if, ingress ) => (o_if, egress )

• Switching is independent of switching unit payload

LSR/OXC only switch based on Label or Lambda

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Label Switched Path (LSP) and Optical Label Switched Path (LSP) and Optical Trail SimilaritiesTrail Similarities

• Explicitly Routed according to constraints

Bandwidth, priority, preemption, policy color, re-optimization

• Unidirectional and Point-to-point

• Payload transparency

• Survivability properties on a per LSP/Optical trail basis

protection and restoration

• Same Label/Lambda cannot be allocated twice on an interface

47AC_054_2000 © 2000, Cisco Systems, Inc.

The IdeaThe Idea

• Adapt IGP extensions for MPLS traffic engineering

• Adapt MPLS constraint-based routing algorithms

• Adapt an MPLS signaling protocol e.g. RSVP-TE to

setup optical channels

• Identify domain specific extensions

• MPS

48AC_054_2000 © 2000, Cisco Systems, Inc.

• Original rational—integrate:

Layer 3 routing—scalability and flexibility

Layer 1 switching—high-performance and terabit capacity

• Now architecture for new services…

++ ==

What we now can do with What we now can do with IP+OpticalIP+Optical

OXC*-LSR

* OXC . . . Optical Cross Connect

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MPMPS Control PlaneS Control Plane

• OXC maintain Neighbour Relationship

• Connected through an IP Link

one or more Data Channels (lambdas, fibers)

one or more Control Channels

• Control Channel in-band or out-band

...

Data Channel

Control Channel

50AC_054_2000 © 2000, Cisco Systems, Inc.

MPMPSS

• Very pragmatic

• Realtime provisioning

• Protection & Restoration

• Overlay and Peer Model

• Framework for Optical Internet

• TBD: UNI, NNI, Control Channel, Policy (IETF COPS Adaption

?), …

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ReferenReferencece

• draft-awduche-mpls-te-optical-*.txt

• draft-kompella-mpls-optical-*.txt

• draft-kompella-mpls-bundle-*.txt

• draft-basak-mpls-oxc-issues-*.doc

• draft-bernstein-mpls-sonet-*.txt• Authors from Cisco Systems, Juniper Network, UUnet, Global

Crossing, AT&T Labs, Level3 Communications, NTT, Marconi, Ciena Corporation, Chromisys, New Access, Sirocco Systems

www.cisco.com