1ac_054_2000 © 2000, cisco systems, inc. intelligent optical networks axel clauberg consulting...
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1AC_054_2000 © 2000, Cisco Systems, Inc.
Intelligent Optical NetworksIntelligent Optical Networks
Axel ClaubergConsulting Engineer
Cisco Systems [email protected]
Axel ClaubergConsulting Engineer
Cisco Systems [email protected]
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
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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
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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)
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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
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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
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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
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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)
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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)
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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
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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
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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
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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
?
?
?
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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
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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
46AC_054_2000 © 2000, Cisco Systems, Inc.
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
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MPMPSS
• Very pragmatic
• Realtime provisioning
• Protection & Restoration
• Overlay and Peer Model
• Framework for Optical Internet
• TBD: UNI, NNI, Control Channel, Policy (IETF COPS Adaption
?), …
51AC_054_2000 © 2000, Cisco Systems, Inc.
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