INF5050 Introduction to optical networking

Transcription

1 INF5050 Introduction to optical networking

2 Background M.Sc. Physics/electronics UIO. Ph.D. Telecommunication NTNU 10 years at Telenor R&D optical network Adjunct associate professor at NTNU Founder of TransPacket AS

3 Scope of lecture Give an introduction to optical networking Highlight main motivation for optical networks Point to currently the hottest topics in optical communication

4 Historic Internet traffic trends 1 1) Prediction made in 2000; It was too optimistic. What do you think will make the traffic grow in the future?

5 Strong growth of mobile and Internet Video and mobile traffic 2014 to 2019: 6X/10X Video and mobile have strict quality demands to the network

6 Propagation through fibre Lightpulses are reflected in the core when hitting the cladding => approximately zero loss Andreas Kimsås, Optiske Nett

7 Transmission capacity in optical fiber (lab) 100Tbit/s D.J. Richardson et al., Nature Photonics, v. 7 p. 354, 2013

8 Transmission capacity in optical fiber (lab) HOT Multicore fibre is next? Current record is: Pb/s research! D.J. Richardson et al., Nature Photonics, v. 7 p. 354, 2013

9 Fibre-cables are spanning the world Source: RAMPART

10 UNINETT " network:" Optical " TRANSPORT" network" Example" What is Metro?" And Access?

11 What is a long distance? 100 m? 10 Km? 100 Km? 1000 Km?

12 What is a long distance? 100 m? LAN 10 Km? Access network 100 km? Metro network 1000 Km? Transport network E.g. subsea-cables

13 Access trends Fibre

14 Paper for student presentation Next-Generation PON Part I: Technology Roadmap and General Requirements Jun-ichi Kani, NTT Corporation Fabrice Bourgart, France Telecom Orange Labs Anna Cui, AT&T Albert Rafel, Malcolm Campbell, and Russell Davey, BT Innovate & Design Silvana Rodrigues, Zarlink Semiconductor

15 Fibre-optical transmission system Transmitter (Laser+ modulator) Fibre Receiver (photodiode + aplifier Attenuation: Some light being absorbed Dispersion: Light of speed wavelength dependent Pulse Spreading Time Time Illustration: Lucent Technologies

16 Wavelength division multiplexing Enables large capacity increase in optical fibers Makes optical networking possible/interresting 2,5 Gb/s = Terminal Fiber 1 Før: channel 1 kanal pr fiber pr fiber Electronic/electrooptical Regenerator Earlier Tidligere utbygging Up to Opptil WDM: WDM: channels kanaler pr fiber pr fiber Now Nåværende utbygging Multiplekser Optical Optisk forsterker amplifier Demultiplekser

17 Course WDM Cheap technology with limited capacity and distance Typically maximum 16 channels and no amplifiers 0,5 2 db/km G.652 G.652C Loss (db/km) 0,4 0,3 0,2 0, nm nm Wavelength (nm)

18 16 channel CWDM using two multiplexers for two different bands C1 (8+1) C1 (8+1) C1 8L EXT EXT C1 8L

19 Long distance optical system Attenuation must be compensated Regeneration Attenuation Dispersion must be compensated Dispersion compensation employing fibre Electronic compensation

20 fibre-optical transmission at longer distances Transmitter (Laser+ modulator) Fibre Receiver (photodiode + aplifier Must be compensated in long distance transmission: Attenuation: Some light being absorbed Dispersion: Light of speed wavelength dependent Pulse Spreading Time Time Illustration: Lucent Technologies

21 Long distance fibre-optical transmission Transmitter (Laser+ modulator) Fibre EDFA Receiver (photodiode + amplifier) To be compensated: Dispersion: Speed of light is wavelength dependent Pulse Spreading Time Time Illustration: Lucent Technologies

22 Available wavelength range depends on amplifier technology Loss (db/km) 0,5 0,4 0,3 0,2 0,1 PDFA 1300 nm EDFA C - band EDFA L - band ALTERNATIVE AMPLIFIER TECHNLOGIES: RAMAN AND SOA Wavelength (nm) Commercially available Still subject to research

23 Erbium Doped Fiber Amplifier (EDFA) Widely deployed in optical networks

24 Dispersion Compensating Fibre (DCF) Negative dispersion compared to transmission fibre Much higher dispersion/km => Shorter fibre than transmission fibre required for achieving zero dispersion

25 Long distance fibre-optical transmission Transmitter (Laser+ modulator) Long Fibre EDFA DCF Receiver (fotodiode + amplifier) Compensation of amplitude and dispersion

26 Fibre optical transmission system Laser & modulator Optical fibre Single modus Amplifier or regenerator Optical fibre Single modus Receiver Electric input data Time Division Multiplexing = TDM Electric output data Wavelength Division Multiplexing (WDM) transmission system: Add lasers & modulators + receivers

27 100 Gb/s per channel fibre optical transmission system Laser & modulator Optical fibre Single modus Amplifier or regenerator Optical fibre Single modus Receiver Electric input data PBS Combine! PBS Electric output data Polarisation multiplexing: Doubles capacity

28 Access Ethernet switches Optical networks Metro Routers/optical switches Core Optical switches/routers Mobile ISP

29 Access Ethernet switches Wavelength services Metro Routers/optical switches Core Optical switches/routers Mobile ISP Wavelength! service! Wavelength! service!

30 Network element functionality (1) 70 % of traffic is through-passing in typical node => Should be able to avoid processing of this traffic. Simple optical network element Static Optical Add-Drop Multiplexer (here: ring network): Fixed wavelengths dropped and added at each node. Not reconfigurable (inaccessible to control system).

31 Network element functionality (2) Traffic bypassing intermediate IP routers => Less load on routers (can be smaller and cheaper) In meshed networks: Used to directly connect node pairs with high traffic between them.

32 Reconfigurable (R-)OADM A flexible add-drop function Use cross-connect for some wavelength/ wavebands Not single wavelength!

33 Networking requirements Wanted: High capacity optical layer network with the following requirements: Support high utilization of resources Support high granularity Support quality needed for strict real-time services Support variable length packets

34 Optical Packet switching More complicated in the optical domain: Higher speeds needed in switches Not (currently) available technology for optical processing of headers etc. The payload information is switched optically Optical buffering is difficult! Separates header and payload Skiller header og nyttelast Demux DMUX er of WDM signals Node Controller (e.g., MPLS) OXC Controller Optical crossconnect (with or without wavelength conversion) Optisk krysskopler Mux of signals to a WDM signal MUX er signaler til WDM signal To OXC-control Header processor Delay <= header length + processing time Optical Optiske buffers buffere (to handle contention on output)

35 Carrier pain Wavelength and OTN services have a high production cost Occupies a physical wavelength or TDM channel resource in the network Wavelengths/TDM channels are limited resources Wavelengths/TDM channels occupies resources end-toend no intermediate additional aggregation possible Ethernet or VPN service preferred as compromise Lower production cost (oversubscription/statistical multiplexing) Does not offer transparency and performance (especially latency) as for wavelengths and OTN channels 35

36 Virtual wavelength service Access Ethernet switches Metro Routers/optical sw itches Core Optical switches/routers Fusion Virtual! wavelength! services! Fusion Fusion Mobile Fusion Virtual! wavelength! service! Fusion ISP ISP ISP Virtual! wavelength! services! Fusion ISP

37 Underutilized circuit (wavelength): FUSION fills it! B C C C C OpMiGua Time between switch will packets insert lower is unused quality L (Internet) traffic D in voids D D Transit traffic passes through on optical layer with minimum or no processing Pure WDM system (circuit) gives low channel utilization For 270 Mb/s video on a 1 Gbps, 70 % of capacity is wasted A D B C Packet Switch Input Queue Output Queue GST lightpath from A D Incoming GST packets destined for node D D D

38 TransPacket H1 the first fusion product Fusion Packet optical networking Add-Drop Muxponder 2 x 10 Gigabit Ethernet line-interfaces 10 x 1 Gigabit Ethernet client-interfaces 10 Gigabit Ethernet wavelength or circuit Sub-wavelength switching: Gigabit Ethernet Packet or circuit paths Optional passive or active optical module CWDM, DWDM, OADM 10GbE GbE Optional optical module

39 Vacant fiber-bandwidth can be utilized Typical scenario Invest at 50% fill rate 10-30% utilization 10 Gb/s Available capacity TransPacket H1 Intelligent Traffic Injection Exploit capacity without affecting existing traffic Monetize on idle capacity Postpone capacity upgrade 0 Utilized capacity 39

40 Example Trondheim-Oslo field trial Utilize network capacity 10G Virtual wavelength 600 km transmission of 10 Gb/s Ethernet More capacity: Intelligent Traffic Injection (ITI) Extra capacity Extra capacity UNINETT Router Trondheim Nokia Siemens WDM system Fibre 600 Km UNINETT Router Oslo WDM WDM TransPacket H1 TransPacket H1 10 Gb/s 10 Gb/s Transport/Metro network

41 Results Trondheim-Oslo stress test Green: Traffic during World championship crosscountry skiing, Trondheim-Oslo both directions Blue: Added SM traffic 1-6 Gb/s of added traffic

42 Controlling the optical network Network management system (NMS) working across vendors and network layers is required Setup and tear down of wavelengths according to capacity needs OADM OADM NMS OADM OADM OADM

43 Controlling across network layers Applications triggers resource usage on servers Server communication triggers network capacity needs IP- routers requires capacity from the optical network Optical network must deliver resources on demand from upper layers

44 Controlling across network layers Applications triggers resource usage on servers Server communication triggers network capacity needs IP- routers requires capacity from the optical network Optical network must deliver resources on demand from upper layers Software defined networks (SDN)?

45 SDN: Hype and research area Software Defined Networking Combined with optical networking

46 SDN goals (carrier view) Centralized control of network resources Control across network layers Control independent of equipment vendor

47 Example application: Load balancing SDN Logical Architecture Applications see the network as a single, logical switch controlled via abstracted API Centralized intelligence and network state knowledge to configure the devices Simplified network devices do not need to process all routing/switching protocols Enterprises and carriers gain vendor-independent control over the entire network from a single logical point, which greatly simplifies the network design and operation. 47

48 The OpenFlow Network Innovation Feature Feature Network Operating System Feature Feature Feature Operating System Feature Specialized Packet Forwarding Hardware Feature Operating System Specialized Packet Forwarding Hardware Feature Feature Operating System Feature Specialized Packet Forwarding Hardware Feature Operating System Feature Specialized Packet Forwarding Hardware Operating System Specialized Packet Forwarding Hardware Source: S.Seetharaman, OpenFlow/SDN tutorial, OFC/NFOEC 2012

49 The OpenFlow Network Innovation 3. Well-defined open API 2. At least one good operating system Feature Extensible, possibly open-source Feature Network Operating System OpenFlow 1. Open interface to hardware Specialized Packet Forwarding Hardware OpenFlow OpenFlow Specialized Packet Forwarding Hardware Specialized Packet Forwarding Hardware OpenFlow Specialized Packet Forwarding Hardware OpenFlow Specialized Packet Forwarding Hardware 49 Source: S.Seetharaman, OpenFlow/SDN tutorial, OFC/NFOEC 2012

50 Disaggregated network motivation Carriers wants to avoid equipment vendor lockin Mix and match equipment from different vendors Typically, equipment from different vendors does not work well together within the same network Equipment need an open interface for configuration through a management system Not proprietary as often found in old equipment Photonic layer interoperability E.g. standardized Reconfigurable Optical Add Drop Multiplexers (ROADM) that can work together

51 Hardware disaggregation using SDN Mix and match boxes from different vendors igure 1: Hardware Disaggregation Using SDN Control ource: Fujitsu and Heavy Reading, 2015

52 Disaggregation examples Optical network components (White-box) Line-terminals, amplifiers, ROADMs From different vendors GPON Optical Line Terminal (OLT) Commodity hardware Hardware functions replaced by software E.g. software router run in microprocessor replaces hardware (chip) based router WHITE-BOX switch or Ethernet Switch Hardware (box) from one vendor Software from another vendor defines layer-2 switching or layer-3 routing

53 White box: Mix and match within the box Choose: Control Software (may be open source) Switch-chip HW Physical box Source: Pica8 white-paper

54 Open optical line-systems (OLS) Optical White-box E.g. Juniper (router vendor) is ready to support whitebox ROADM Enable service provisioning across protocol layers. Enabling use of OLS in metro packet networks Juniper Networks embraces open optical line systems, Lumentum whitebox ROADM November 1, 2017

55 White-box example: Facebook Voyager Optical Muxponder with packet switch ASIC 4 X 200 Gb/s output to optical line 12 X 100 Gb/s input Figure 2: Voyager transponder with 12 QSFP28 ports and 4 x200g DWDM line ports.

56 SDN Multidomain control: Much more than openflow R. Vilalta et.al. ECOC 2015: First experimental demonstration of distributed cloud and heterogeneous network orchestration with a common Transport API for E2E service provisioning and recovery with QoS Control Orchestration Protocol (COP) for communication with controllers for each domain and vendor. B A)

57 Summary Optical fibres are the ultimate transmission medium Long range, Terabit capacity now, petabit in research Optical networking enables switching of high bitrate wavelengths A common control and management of the network layers is required Preferably standardized working across vendors opening up for competition Is disaggregation and SDN the solution?

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