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Intelligent Optical Networks

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Presentation on theme: "Intelligent Optical Networks"— Presentation transcript:

1 Intelligent Optical Networks
Axel Clauberg Consulting Engineer Cisco Systems

2 Agenda The Need for Optical Networks
Dense Wavelength Division Multiplexing (DWDM) Overview Basics Fibers & Physics Long Haul, Metro WDM DWDM Junctions Wavelength Routing – MPlS

3 The Need for Optical Networks

4 Driving Factors Exponential IP traffic growth
ISPs: Factor growth per year ...sometimes only throttled by congested US links...

5 Driving Factors R&D/EDU
Distance and Lifelong Learning High resolution, studio quality video Telemedicine Digital Libraries High performance distributed computing More to come…

6 Driving 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

7 New 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)

8 Current Carrier Situation - SDH
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 Ring A Ring B Ring C

9 Basic Layout of an SDH Multiplexer
West Aggregate Tx/Rx East Aggregate Tx/Rx Matrix Cards Tributary Cards PDH Trib. Fiber Tributaries STM-1or STM-4 Level (to sub networks) Electr. Tributaries STM-1 (for connection towards radio relays) 2/34/45/140 Mb/s Aggregate and matrix cards are also referred to as traffic cards Note: Common cards such as CPU, power supplies, or fans, have not been displayed

10 SDH 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“)

11 Global Optical Networks Markets 1999-2004
Source : Pioneer 1999

12 DWDM Overview

13 WDM Applications Campus WDM Metro WDM Long Haul WDM 1995 2000 2005

14 Enterprise Optical Networking
Aggregation FE, GE FDDI ATM/ SDH, DPT STM-4c STM-16c E3 STM1 Data & Storage ESCON FICON Fiber Channel

15 WDM System Transmitter
Wavelength Converter Passive Optical Muliplexer 1300 nm 850 nm Ch 1 Ch 2 Ch n

16 WDM System Function Mux & Demux 1 2 Wavelength Converter n Ch 1 Ch 2
Ch n 1 2 n Mux & Demux

17 WDM History First 2 wavelength (l) 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) l = c / f (c = speed of light, f = frequency)

18 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 ( ) nm region called RED BAND (C) , 24 channels 100 GHz spaced 48 channels 50 GHz spaced can be multiplexed In the ( ) nm region called INFRA-RED BAND (L), 32 channels 100 GHz spaced 64 channels 50 GHz spaced can be multiplexed Conventional Band (C) Long Band (L) 1530 nm 1540 nm 1550 nm 1560 nm 1570 nm 1580 nm 1590 nm 1600 nm BLUE BAND RED BAND INFRA-RED BAND

19 Analog Transmission Effects
Attenuation: Reduces power level with distance Dispersion and Nonlinearities: Erodes clarity with distance and speed There are two main types of analog transmission effects. The first is attenuation, meaning that your signal becomes smaller over time, as shown at the top of the slide. The other, more important, type of effect is dispersion and non-linearities. Dispersion and non-linearity does not reduce the strength of your signal; rather, it introduces noise that smears the signal. When signals are transmitted over fiber optics, these two effects combine. The signal detected - and to be recovered - is a much smaller, noisier signal, an analog problem to recover this digital signal from the noisy environment. Signal detection and recovery is an analog problem

20 Fiber Attenuation ( ) [ ] Attenuation db Km ~ 200 ppb OH Infra-red
[ ] ~ 200 ppb OH Infra-red Absorbtion Rayleigh scattering ( ) 1 4 OH Peaks “First Window” “Third” “Second” Wavelength (nm)

21 Optical Amplifiers: Principle

22 Optical Transmission: Chromatic Dispersion
Different colors of light travel at different speeds Spectral broadening caused by differential group delay

23 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

24 Dispersion Slopes DWDM band DS SMF NZD+ NZD- G.653 G.652 G.655 -20 -15
-10 -5 5 10 15 20 25 Dispersion (in ps/nm/km) 1350 1370 1390 1410 1430 1450 1470 1490 1510 1530 1550 1570 1590 1610 1630 1650 Wavelength (in nm)

25 4-Wave Mixing (4WM) 1) Effect and consequences 2) Counteractions
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

26 Non Linear Effects: FWM continued...
9 FWM products generated, 3 fall on signal channels f f Power (a.u.) f112 f332 f123 f132 f231 f113 f223 f221 f331 Frequency f1 f2 f3

27 Non Linear Effects: FWM continued...
9 FWM products generated, none fall on signal channels f f Power (a.u.) f223 f123 f231 f132 f332 f113 f112 f221 f331 f1 f2 f3 Frequency

28 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

29 WDM Topologies Point to Point Add and Drop

30 Case Study - A European Service Provider
Lots of interconnected DWDM structures Helsinki Madrid Problem: E2E Provisioning, Protection

31 Today’s DWDM Junctions
2 1 4 5 3 !! 6 Static Lightpath (LP) Configuration Long Provisioning Time High Operational Costs Installing new LP is potential Risk to cut another LP

32 Wavelength Routing

33 Wavelength Routing makes DWDM Junctions Scale
2 1 1 3 4 3 2 4

34 DWDM Junction Evolution
Innovation Wavelength Router with an integrated optical solution Wavelength Router running an Optical Routing Protocol Fiber Patch Panel Time

35 A Wavelength Routing Network is ...
a Mesh of Optical Transmission and Switching Equipment P-t-P DWDM System Optical Cross Connect (OXC)

36 A Wavelength Routing Network is ...
. . . , which provides dynamic Point-to-Point Connections SONET/SDH, Gigabit Ethernet,  SONET/SDH l Gigabit Ethernet

37 A Wavelength Routing Network is ...
. . . to attached Internetworking Devices. IP Routers, SONET/SDH Muxes, ATM Switches, ... ? SDH Mux Black Box ? IP Router ?

38 The Key Element is the Wavelength Router
Control Plane: Wavelength Routing Intelligence Data Plane: Optical Cross Connect Matrix Unidirectional DWDM Links to other Wavelength Routers Unidirectional DWDM Links to other Wavelength Routers Single Channel Links to IP Routers, SDH Muxes, ...

39 Data Plane First Generation Wavelength Router
Cross-Connect Incoming Interface Outgoing Interface l1 Hybrid OXC: O/E Conversion, Switching, E/O Conversion Pure OXC: Wavelength Conversion l3 Animated

40 Data Plane Wavelength Router with integrated DWDM
Cross-Connect Incoming Interface Incoming Wavelength Outgoing Interface Outgoing Wavelength l1 Hybrid OXC: O/E Conversion, Switching, E/O Conversion Pure OCX: Wavelength Conversion l3

41 Control Plane Wavelength Routing Intelligence
Resource Discovery Topology State Maintenance Reliable broadcast Path Selection Constraint-based Routing Optical Channel Management Path placement Path maintenance Path revocation

42 Existing Control Planes
Method Standard Body Routing Signaling Available OXC None Proprietary Proprietary Trials ATM ATM Forum PNNI PNNI Deployed MPLS IP-LSR IETF Constraint-based LDP / RSVP Deployed Source: John Drake -- MPLS Conference 1999

43 Uniform Control Plane Paradigm
Method Standard Body Routing Signaling Available OXC IETF Constraint-based MPLS-TE Future ATM IETF Constraint-based MPLS-TE Trials/ Deployed MPLS IP-LSR IETF Constraint-based MPLS-TE Deployed Source: John Drake -- MPLS Conference 1999

44 What we already did with IP+ATM
Original rational—integrate: Layer 3 routing—scalability and flexibility Layer 2 switching—high-performance and traffic management Now architecture for new services… IP-LSR* ATM-LSR* + = * LSR Label Switch Router

45 LSR 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

46 Label Switched Path (LSP) and Optical Trail 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

47 The 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 MPlS

48 What we now can do with IP+Optical
Original rational—integrate: Layer 3 routing—scalability and flexibility Layer 1 switching—high-performance and terabit capacity Now architecture for new services… OXC*-LSR + = * OXC Optical Cross Connect

49 MPlS Control Plane OXC maintain Neighbour Relationship
Data Channel ... Control Channel 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

50 MPlS Very pragmatic Realtime provisioning Protection & Restoration
Overlay and Peer Model Framework for Optical Internet TBD: UNI, NNI, Control Channel, Policy (IETF COPS Adaption ?), …

51 Reference 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


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