Basics overview of Optical networking. Kurosh, August/2014

Transcription

1 Basics overview of Optical networking Kurosh, August/2014

2 Agenda Basic optical terminologies (fiber and DWDM device) DWDM building blocks and enabling technologies Terrestrial deployments Submarine deployment OTN overview

3 Some terminology Decibels (db): unit of level (relative measure) X db is 10 -X/10 in linear dimension e.g. 3 db Attenuation = = Standard logarithmic unit for the ratio of two quantities. In optical fibers, the ratio is power and represents loss or gain. Decibels-milliwatt (dbm) : Decibel referenced to a milliwatt X mw is 10 log 10 (X) in dbm, Y dbm is 10 Y/10 in mw. 0dBm=1mW, 17dBm = 50mW Wavelength ( ): length of a wave in a particular medium. Common unit: nanometers, 10-9 m (nm) 300nm (blue) to 700nm (red) is visible. In fiber optics primarily use 850, 1310, & 1550nm Frequency ( ): the number of times that a wave is produced within a particular time period. Common unit: TeraHertz, cycles per second (Thz) Wavelength x frequency = Speed of light x = C Source: Cisco

4 Some more terminology Attenuation = Loss of power in db/km The extent to which lighting intensity from the source is diminished as it passes through a given length of fiber-optic (FO) cable, tubing or light pipe. This specification determines how well a product transmits light and how much cable can be properly illuminated by a given light source. Chromatic Dispersion = Spread of light pulse in ps/nm-km The separation of light into its different coloured rays. ITU Grid = Standard set of wavelengths to be used in Fibre Optic communications. Unit Ghz, e.g. 100Ghz, 50GHz Optical Signal to Noise Ration (OSNR) = Ratio of optical signal power to noise power for the receiver Lambda = Name of Greek Letter used as Wavelength symbol ( ) Optical Supervisory Channel (OSC) = Management channel

5 Bit Error Rate ( BER) BER is a key objective of the Optical System Design Goal is to get from Tx to Rx with a BER < BER threshold of the Rx BER thresholds are on Data sheets Typical minimum acceptable rate is 10E-12 for non DSP enhanced DWDM deployments.

6 Optical Budget Basic Optical Budget = Output Power Input Sensitivity Pout = +6 dbm R = -30 dbm Budget = 36 db Optical Budget is affected by: Fiber attenuation Splices Patch Panels/Connectors Optical components (filters, amplifiers, etc) Bends in fiber Contamination (dirt/oil on connectors)

7 Fiber Fundamentals Light is a form of electro-magnetic radiation which is characterized by having a particular wavelength and frequency. Attenuation Dispersion Nonlinearity It May Be a Digital Signal, but It s Analog Transmission Transmitted Data Waveform Waveform After 1000 Km

8 Attenuation (db/km) Dispersion (ps/nm km) Fiber standards shifted fiber unshifted fiber Wavelength (nm) EDFA band G652 G653 G654 Single Mode dispersion optimized at 1310nm G652B, G652C and G652D (Low water Dispersion Shifted Fiber G655 Non Zero Dispersion Shifted Fiber G657.A/B (Low Band-loss) Hole-assisted fiber (HAF) Photonic band-gap fiber (PBGF) Cutoff Shifted Fiber

9 Fiber nonlinearities Category 1: Occurs because of scattering effects in the fiber medium due to the interaction of light waves with phonons (molecular vibrations) in the silica medium. (next slide) Category 2: Dependence of refractive index on the optical power. (Have negative impact on DWDM) Self-Phase Modulation Cross-Phase Modulation Four-Wave Mixing 19. desember

10 Fiber nonlinearities and Scattering Linear Scattering Loss Rayleigh Scattering: It results from the non-homogeneities of the random nature occurring on a small scale particles compared with the wavelength of the light. Mie Scattering: It results from the non-homogeneities of the random nature occurring on a large scale particles compared with the wavelength of the light. It is usually in the forward direction. Non Linear Scattering Loss: Energy gets transferred from one light wave to another wave at a longer wavelength (or lower energy). The lost energy is absorbed by the molecular vibrations, or phonons, in the medium. Pump and stokes wave: As the pump propagates in the fiber, it loses power and the Stokes wave gains power Stimulated Brillouin: pump wave is the signal wave, and the Stokes wave is the unwanted wave stimulated Raman scattering: the pump wave is a high-power wave, and the Stokes wave is the signal wave that gets amplified at the expense of the pump wave. 19. desember

11 Attenuation Kilde: NSN ACADEMY

12 Optical Spectrum Kilde: NSN ACADEMY

13 DWDM: building blocks and enabling technologies 19. desember

14 Why DWDM The Business Case 40km Conventional TDM Transmission 10 Gbps 40km 40km 40km 40km 40km 40km 40km 40km TERM TERM RPTR 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR 1310 TERM RPTR 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR 1310 TERM RPTR 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR RPTR RPTR RPTR RPTR RPTR RPTR RPTR TERM TERM TERM TERM OC-48 OC-48 OC-48 OC-48 OA DWDM Transmission 10 Gbps 120 km 120 km 120 km OA OA OA OC-48 OC-48 OC-48 OC-48 4 Fibers Pairs 32 Regenerators 1 Fiber Pair 4 Optical Amplifiers

15 DWDM History Early WDM (late 80s) Two widely separated wavelengths (1310, 1550nm) Second generation WDM (early 90s) Two to eight channels in 1550 nm window 400+ GHz spacing DWDM systems (mid 90s) 16 to 40 channels in 1550 nm window 100 to 200 GHz spacing Today s DWDM systems 160 channels in 1550 nm window (e.g. Siemens 160 and Alcatel 192 channels) 50 and 25 GHz spacing

16 Characteristics of a WDM Network Sub-wavelength Multiplexing or MuxPonding Ability to put multiple services onto a single wavelength

17 Characteristics of a WDM Network Wavelength Characteristics Transparency Monitori Can carry multiple protocols on same fiberng can be aware of multiple protocols Wavelength spacing 50GHz, 100GHz, 200GHz Defines how many and which wavelengths can be used Wavelength capacity Example: 1.25 Gbit/s, 2.5 Gbit/s, 10 Gbit/s, 40 Gbit/s, 100Gbit/s

18 Optical Transmission Bands and DWDM grid Band Wavelength (nm) New Band S-Band C-Band L-Band U-Band ad/repository/itu-dwdm.pdf

19 DWDM Components 850/ xx n Transponder 3 Optical Multiplexer n Optical De-multiplexer Band- and Channel Mux/Demux Optical Add/Drop Multiplexer (OADM)

20 More DWDM Components Optical Amplifier (EDFA) Optical Attenuator Variable Optical Attenuator Dispersion Compensator (DCM / DCU)

21 Typical DWDM Network Architecture DWDM SYSTEM DWDM SYSTEM VOA EDFA DCM DCM EDFA VOA Service Mux (Muxponder) Service Mux (Muxponder)

22 Transponders Converts broadband optical signals to a specific wavelength via optical to electrical to optical conversion (O-E-O) Used when Optical LTE (Line Termination Equipment) does not have tight tolerance ITU optics Performs 2R or 3R regeneration function Receive Transponders perform reverse function OEO 1 From Optical OLTE OEO 2 To DWDM Mux n OEO Low Cost IR/SR Optics Wavelengths Converted

23 Laser transponders Power Non DWDM Laser Fabry Perot on client side c DWDM Laser Distributed Feedback (DFB) On line sdie Power c Spectrally broad Unstable center/peak wavelength Dominant single laser line Tighter wavelength control Mirror Partially transmitting Mirror Active medium Amplified light

24 DWDM Receiver Requirements I Receivers Common to all Transponders Not Specific to wavelength (Broadband)

25 Attenuation and amplifiers P in G P out = GP in 19. desember

26 Optical Attenuation Pulse amplitude reduction limits how far Attenuation in db Power is measured in dbm: P i P 0 T T

27 Combating attenuation SOA (Semiconductor Optical Amplifier) EDFA (Erbium Doped Fiber Amplifiers) SOA RAMAN (based on Stimulated Raman Scattering (SRS) EDFA TX Er 3+ doped Fiber RX pump 980nm TX Transmission Fiber RX RAMAN pump Raman 1535

28 Erbium Doped Fiber Amplifier Isolator Coupler Coupler Isolator Erbium-Doped Fiber (10 50m) Pump Laser Pump Laser Simple device consisting of four parts: Erbium-doped fiber An optical pump (to invert the population). A coupler An isolator to cut off backpropagating noise Amplified Spontaneous Emission (ASE) is main source of noise in EDFA

29 OA Gain and Fiber Loss Typical Fiber Loss 25 THz 4 THz OA Gain OA gain is centered in 1550 window OA bandwidth is less than fiber bandwidth

30 Raman Amplifiers Raman Fibre Amplifiers (RFAs) rely on an intrinsic nonlinearity in silica fibre Variable wavelength amplification: Depends on pump wavelength For example pumping at 1500 nm produces gain at about nm RFAs can be used as a standalone amplifier or as a distributed amplifier in conjunction with an EDFA

31 Distributed Raman Amplification (I) Raman pumping takes place backwards over the fibre Gain is a maximum close to the receiver and decreases in the transmitter direction Long Fibre Span Transmitter EDFA Optical Receiver Raman Pump Laser

32 Optical Power Distributed Raman Amplification (II) With only an EDFA at the transmit end the optical power level decreases over the fibre length With an EDFA and Raman the minimum optical power level occurs toward the middle, not the end, of the fibre. EDFA + Raman EDFA only Distance Animation

33 Optical Signal-to Noise Ratio (OSNR) Signal Level X db Noise Level Depends on : Optical Amplifier Noise Figure: (OSNR) in = (OSNR) out NF EDFA Schematic (OSNR) (OSNR) out in P in NF Target : Large Value for X

34 Dispersions and Dispersion compensating modules 19. desember

35 Types of Dispersion Chromatic Dispersion Different wavelengths travel at different speeds Causes spreading of the light pulse Polarization Mode Dispersion (PMD) Single-mode fiber supports two polarization states Fast and slow axes have different group velocities Causes spreading of the light pulse

36 Pulse Delay (ps) Dispersion Chromatic Dispersion (Review) + Pulse Spreading 0 Wavelength (nm) - 0 Wavelength Time Time Different Wavelengths of light travel at slightly different velocities in the glass fiber Negative ( normal ) dispersion: red light (longer ) faster Positive ( anomalous ) dispersion: blue light (shorter ) faster Leads to pulse broadening or distortion RBK-TWCable 6/97 Minimum dispersion at the Zero Dispersion Wavelength ( 0 ) 18 ps/(nm-km)

37 A Snapshot on Chromatic Dispersion Affects single channel and DWDM systems A pulse spreads as it travels down the fiber Inter-symbol Interference (ISI) leads to performance impairments Degradation depends on: laser used (spectral width) bit-rate (temporal pulse separation) Different SM types Interference

38 Limitations From Chromatic Dispersion Dispersion causes pulse distortion, pulse "smearing" effects Higher bit-rates and shorter pulses are less robust to Chromatic Dispersion Limits "how fast and how far 10 Gbps 60 Km SMF-28 t 40 Gbps 4 Km SMF-28 t

39 Combating Chromatic Dispersion Dispersion Compensating Fiber Dispersion compensating based on Fiber Bragg Grating (FBG) Transmitters with narrow spectral width Use DSF and NZDSF fibers with negative and positive dispersion coeffisient (G.653 & G.655)

40 Dispersion Compensating Fiber Dispersion Compensating Fiber: By joining fibers with CD of opposite signs (polarity) and suitable lengths an average dispersion close to zero can be obtained; the compensating fiber can be several kilometers and the reel can be inserted at any point in the link, at the receiver or at the transmitter

41 Fiber Bragg Grating This is invented at Communication Research Center, Ottawa, Canada The FBG has changed the way optical filtering is done The FBG has so many applications The FBG changes a single mode fiber (all pass filter) into a wavelength selective filter

42 Fiber Brag Grating (FBG) Basic FBG is an in-fiber passive optical band reject filter FBG is created by imprinting a periodic perturbation in the fiber core The spacing between two adjacent slits is called the pitch Grating play an important role in: Wavelength filtering Dispersion compensation Optical sensing EDFA Gain flattening Single mode lasers and many more areas

43 Bragg Grating formation 2 sin( / 2) uv

44 Reflection at FBG

45 Dispersion Compensation Longer wavelengths take more time Reverse the operation of dispersive fiber Shorter wavelengths take more time

46 Cumulative Dispersion (ps/nm) Dispersion Compensation Total Dispersion Controlled No Compensation With Compensation Distance from Transmitter (km) Transmitter Dispersion Compensators Dispersion Shifted Fiber Cable

47 Dispersion compensating by fiber management large mode field (LMF) fiber high dispersion fiber (HDF), also called dispersion shifted fiber nondispersion shifted fiber (NDSF) 19. desember

48 How Far Can I Go Without Dispersion? Distance (Km) = Specification of Transponder (ps/nm) Coefficient of Dispersion of Fiber (ps/nm*km) A laser signal with dispersion tolerance of 3400 ps/nm is sent across a standard SMF fiber which has a Coefficient of Dispersion of 17 ps/nm*km. It will reach 200 Km at maximum bandwidth. Note that lower speeds will travel farther.

49 Polarization Mode Dispersion All electromagnetic waves are Characterized by polarization In Which the electric field (E) of The wave is oscillating. Caused by ovality of core due to: Manufacturing process Internal stress (cabling) External stress (trucks) Only discovered in the 90s Most older fiber not characterized for PMD

50 Polarization Mode Dispersion (PMD) Ey n x Ex Pulse As It Enters the Fiber n y Differential group delay DGD (Δτ) DGD is measured in ps/ km Spreaded Pulse As It Leaves the Fiber The optical pulse tends to broaden as it travels down the fiber; this is a much weaker phenomenon than chromatic dispersion and it is of little relevance at bit rates of 10Gb/s or less According standard: DGD shouldn't exceed 30% of the bit period or DGDmax (30ps for 10Gbit/s or 7,5ps for 40Gbit/s). BUT when designing link the overall PMD(DGD) shouldn t exceed 1/3 (safety factor) of DGDmax < 0.06 ps/sqrt(km)

51 Combating Polarization Mode Dispersion Factors contributing to PMD Bit Rate Fiber core symmetry Environmental factors Bends/stress in fiber Imperfections in fiber Solutions for PMD Improved fibers Regeneration Follow manufacturer s recommended installation techniques for the fiber cable

52 The 3 R s of Optical Networking A Light Pulse Propagating in a Fiber Experiences 3 Type of Degradations: Pulse as It Enters the Fiber Pulse as It Exits the Fiber Loss of Energy Shape Distortion Phase Variation Loss of Timing (Jitter) (From Various Sources) t t s Optimum Sampling Time t t s Optimum Sampling Time

53 The 3 R s of Optical Networking (Cont.) The Options to Recover the Signal from Attenuation/Dispersion/Jitter Degradation Are: Pulse as It Enters the Fiber Pulse as It Exits the Fiber Amplify to Boost the Power Re-Shape DCU Phase Variation Phase Re-Alignment Re-Generate t t s Optimum Sampling Time t t s Optimum Sampling Time O-E-O Re-gen, Re-shape and Remove Optical Noise t s Optimum Sampling Time t

54 19. desember

55 Multiplexer / Demultiplexer DWDM Mux DWDM Demux Wavelength Multiplexed Signals Wavelength Multiplexed Signals Wavelengths Converted via Transponders Wavelengths separated into individual ITU Specific lambdas

56 (De)Multiplxer technologies Dielectric filters FBG Free Space Diffraction Grattings Mach-Zehnder based devices Arrayed Waveguide Grating (AWG) 19. desember

57 Optical Filter Technology Thin-Film Filter 1, 2, 3,... n Dielectric Filter 2 1,, 3,... n Well established technology, up to 200 layers

58 Array Waveguide Grating Mux/Demux Fiber4sale.com

59 Array Waveguide Operation An Array Waveguide Demux consists of three parts : 1st star coupler, Arrayed waveguide grating with the constant path length difference 2nd star coupler. The input light radiates in the 1st star coupler and then propagates through the arrayed waveguides which act as the discrete phase shifter. In the 2nd star coupler, light beams converges into various focal positions according to the wavelength. Low loss, typically 6 db Dublin institute of technology

60 Simple De-multiplexing Function Reflected Wavelength 2 n Peak Reflectivity R max = tanh 2 (kl) B eff

61 Optical Add/Drop Filters (OADMs) OADMs allow flexible add/drop of channels Drop Channel Drop & Insert Add Channel Pass Through loss and Add/Drop loss

62 Extended Add/Drop Mux

63 ROADM node 19. desember

64 Transmission Errors Errors happen! A old problem of our era (PCs, wireless ) Bursty appearance rather than distributed Noisy medium (ASE, distortion, PMD ) TX/RX instability (spikes, current surges ) Detect is good, correct is better Information Transmitter Noise Transmission Channel Information Receiver

65 Error Correction Error correcting codes both detect errors and correct them Forward Error Correction (FEC) is a system adds additional information to the data stream corrects eventual errors that are caused by the transmission system. Low BER achievable on noisy medium

66 FEC Performance, Theoretical FEC gain BER Bit Error Rate 1 BER without FEC Coding Gain BER floor BER with FEC Received Optical power (dbm)

67 FEC in DWDM Systems 9.58 G G G 9.58 G IP FEC FEC IP SDH FEC FEC SDH.... ATM FEC FEC ATM 2.48 G 2.66 G 2.66 G 2.48 G FEC implemented on transponders (TX, RX, 3R) No change on the rest of the system

68 Uni Versus Bi-directional DWDM DWDM systems can be implemented in two different ways Uni-directional: wavelengths for one direction travel within one fiber two fibers needed for full-duplex system Uni -directional Fiber Fiber Bi-directional: a group of wavelengths for each direction single fiber operation for full-duplex system Fiber Bi -directional

69 Uni Versus Bi-directional DWDM (cont.) Uni-directional 32 channels system Full band 32 ch full duplex Channel Spacing 100 GHz Full band Bi-directional 32 channels system Blue-band 16 ch full duplex Channel Spacing 100 GHz Red-band

70 DWDM Protection Review Unprotected Client Protected Splitter Protected Y-Cable and Line Card Protected

71 3R with Optical Multiplexer and OADM Back-to-back DWDM Express channels must be regenerated Two complete DWDM terminals needed N N7 Optical add/drop multiplexer Provides drop-and- continue functionality Express channels only amplified, not regenerated OADM Reduces size, power and cost N7 N7

72 DWDM topology

73 Submarine Cable

74 What makes a Submarine Cable Network Terminal Equipment Power Feeding Equipment Cable Branching unit Repeater Cable station Network Management 90

75 Functions of Submarine Network 91

76 Functions & Terminologies 92

77 Submarine Wetplant & components Wet plant comprises the following equipment/components: Undersea Cable Land Cable Optical Fiber Cable joints Undersea Repeaters Gain equalizers Branching Units 93

78 Major Components of Submarine system SLTE & Wetplant NMS Cable Station NMS Full Fiber Drop Branching Unit Undersea Repeater SL-17 Undersea Cable CTE Beach Joint RL Cable HV Power HV Shield PLINB WTE + TLA N Channels TRPDR 1 TRPDR 2 TRPDR 3 STM-16/ STM-64 ADM Ocean Ground Ground LTE #1 TRPDR n OGPP PFE N Channels TRPDR 1 TRPDR 2 TRPDR Transponder HV : High Voltage LME : Line Monitoring Equipment OGPP : Ocean Ground Protection Panel PFE : Power Feed Equipment RL : Rodent Lightning Building Ground COTDR LME TRPDR 3 TRPDR n STM-16/ STM-64 ADM TLA : Terminal Line Amplifier LTE #2 WTE: Wavelength Termination Equipment 94

79 Submarine Transmission Line Terminating Equipment TRPDR 1 WTE Note: Any module of the LTE may not be included depending on the specific requirements of the system (distance, bit rate, SDH or SONET equipment, etc.) IP ADM 10 Gbps (S- 64.2) Interface Line Amp One Fiber-Pair OXC N-1 N-1 N x 10Gbps ATM N N Submarine Cable (optional) ILE Line Monitoring Wavelengths (only for repeatered systems) 95

80 UnderSea Repeaters Repeaters use state-of-the-art optical amplifier technology to achieve high performance and reliability in the transmission of multiple wavelength channel signals on multiple fiber pairs which normally use 980nm Pump for boosting up optical signal 96

81 Inside Repeater & different types Amplif ier Pair Chassis Locking Plate Heat Transf er Plate Superv isory Erbium Amplif iers Power Supply Pump Unit Control Circuit 1/2/3/4 up-to 8 Amplifier pairs per Repeater Low/High Gain Repeaters. Low noise & Wide BW Repeaters 980 nm Pumps used in Repeaters. 97

82 Fault localization multi-sidetone line monitoring equipment (MST LME) MST LME is located at cable station. Signal is supplied at two wavelengths (Only one in Svalbard, THz) A change in undersea transmission that might occur during the life of the system is seen as a difference between loop gain measurements made before and after a change has occurred. 98

83 Optical Fault Localization What is a OTDR? Optical Time Domain Reflectometer - also known as an OTDR, is a hardware device used for measurement of the elapsed time and intensity of light reflected on optical fiber. How it works? The reflectometer can compute the distance to problems on the fiber such as attenuation and breaks, making it a useful tool in optical network troubleshooting. The intensity of the return pulses is measured and integrated as a function of time, and is plotted as a function of fiber length. What is a COTDR? Coherent Optical Time Domain Reflectometer - also known as a COTDR, An instrument that is used to perform out of service backscattered light measurements on optically amplified line systems. How it works? A fiber pair is tested by launching a test signal into the out going fiber and receiving the scattered light on the in-coming fiber. Light scattered in the transmission fiber is coupled to the incoming fiber in the loop-back couplers in each amplifier pair in a repeater. 99

84 OTDR Vs COTDR Repeater Repeater Repeater OTDR Light Pulse Backscatter HLLB HLLB HLLB OTDR can only measure upto first repeater Repeater Repeater Repeater Light Pulse COTDR HLLB HLLB HLLB Backscatter COTDR can cross the repeaters & can measure till opposite end terminal 100

85 Remote Optical Pumping Amplifier (ROPA) 19. desember

86 Optical Transport Network

87 Optical Transport Network (OTN): Definition and History Definition Optical networks are comprised of functionality providing transport, multiplexing, switching, supervision and survivability of client signals that are processed predominantly in the photonic domain. Described in the ITU-T Recommendation G.709 (2003), OTN adds operations, administration, maintenance, and provisioning (OAM&P) functionality to optical carriers, specifically in a multi-wavelength system such as dense wavelength division multiplexing (DWDM). The idea: Introduced as Digital Wrapper by Bell-labs in the late 1990s Approval of first version of standard by ITU-T in 2001

88 Why OTN A common way to support transparent transport of any client signals (on DWDM systems) Client signal agnostic Strong Forward Error Correction Monitoring capability for multi domain network services More Levels of Tandem Connection Monitoring (TCM) Switching Scalability

89 ITU-T and OTN work G.709: Interfaces for the optical transport network (OTN) G.798: Functional characteristics of optical networking equipment G.870 contains OTN Terms and Definitions. G.872: Architecture of Optical Transport Networks G.800: Unified Framework for the Architecture of Transport Networks OTN Management: A number or Recs worked out in Q.14/15. G.Sup39: Optical system design and engineering considerations G.959.1: Optical transport networks physical layer interfaces (black link) G.693: Optical interfaces for intra-office systems (up to 2 km) G.694.1: flex grid G.697 Optical monitoring for DWDM systems G.680, G.rmon: OXC, ROADM

90 Pre OTN, DWDM solution Carrier A NE Carrier B Carrier A NE NE NE NE NE Client devices No interopbability between vendors and carriers Signal had to back to client signal level Client devices Vendor proprietary Client signal adaption and transport mechanism

91 Post OTN, DWDM solution Carrier A NE Carrier B Carrier A NE NE NE NE NE Client devices OTN interfaces as common interface Customer devices OTN based Client signal adaption and transport mechanism

92 OTN, Basic functionalities and building blocks

93 Tandem Connection Monitoring (TCM) Though the lightpath is an end-to-end OCh entity, it can be monitored by intermediate systems (e.g. by performing FEC) Signaling is carried by separate fields (TCM) of the ODUk channelassociate overhead 6 levels of TCM are allowed to perform nested, cascaded or overlapping monitoring sessions

94 Layers in OTN hierarchy Electrical Domain Client signals (e.g. STM-N, IP, Ethernet, OTN ODUk Optical Domain OPU ODU Optical channel Payload Unit Optical channel Data Unit Optical channel Transport Unit Optical channel sublayer (OCh) Optical multiplex section (OMS) Optical transmission section (OTS) FEC OTU OCh OMS OCCoh OTS Mapping of client signals on OPU is going through different mapping procedures. e.g. AMP, BMP, GFP and GMP

95

96 OTN rates and multiplexing Source: Yann Loussouarn, Damien Martinet, Fabrice Herviou, Patrice Robert ( France Telecom Orange Labs)

97 OTN Frame format OCh overhead OCh payload FEC Area Frame rate changes depends on ODUk level, but frame format remains untouched

98 OTN benefits: client signal MUX Unprecedented flexibility in client signal mapping!!!! Higher order and Lower order MUX Phy Flow (VLAN) ODUflex HO ODUk ( ) LO maps non-otn signals of ANY kind HO maps OTN signals Phy Flow (VLAN) ODUflex ODUflex HO ODUk ( ) Designed for data traffic i.e. focus on packet switched clients Phy ODUflex HO ODUk ( ) Advanced MUX paths (extended OTN) Phy ODUj ODU0 (1GE), ODU2e, ODU4 (100 GE) added for extended flexibility Phy HO ODUk ( ) ODUFlex can map ANY bitrate client flow Physical interface Client interface Transport entity full decoupling of client and network PHY Fastest IP over WDM solution IPoOTNoWDM Source: GN3-JRA1-T1

99 one typical Coriant card 19. desember

100 OTN, Switching and traffic grooming

101 ODU switching One possible scenario: - ODU0 switching - Multiplexing / Demultiplexing

102 DWDM OTUk Optical Switch ODU-XC ODU switch OTU-x, GbE, 10GbE, 40GbE, STMxxx, FCx and other type of client signals Clients Separation between wavelength service and sub-wavelength services

103 DWDM OTUk Optical Switch ODU-XC ODU switch OTU-x, GbE, 10GbE, 40GbE, STMxxx, FCx and other type of client signals Clients Integrated wavelength and Sub-wavelength

104 DWDM OTUk Optical Switch ODU-XC ODU switch OTU-x, GbE, 10GbE, 40GbE, STMxxx, FCx and other type of client signals Client Integrated wavelength and Sub-wavelength

105 OTN use scenario (1) Grooming As a grooming device to gather client signals with any different bitrates to a bigger pipe at transport level.

106 Multi-Rate vs. OTN: Comparing Approaches to Build Scalable, Cost-Effective 100Gb/s Networks, ECOC2012 P5.11, Marco Bertolini et al, Grooming at 100G network Comparing pure WDM equipments at both 10Gb/s and 100Gb/s line rate, to a pure100gb/s design where electrical OTN switches are integrated with WDM equipment.

107 OTN Summary OTN is the common layer which stitches together the optical domain with higher order networking layers Advanced AOM&P functionalities (GMPLS-ready) Excellent solution for multi-domain service provisioning OTN became the common interface of choose between different network domain Major vendors already offer advanced OTN functionalities switching and traffic grooming based on OTN will add flexibility without adding another complex network layer Highly scalable, future-proof technology Protection and restoration opportunity on different signal level

108 Backup slides 19. desember