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Davide Careglio, Universitat Politècnica de Catalunya (UPC), careglio@ac.upc PowerPoint Presentation
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Davide Careglio, Universitat Politècnica de Catalunya (UPC), careglio@ac.upc

Davide Careglio, Universitat Politècnica de Catalunya (UPC), careglio@ac.upc

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Davide Careglio, Universitat Politècnica de Catalunya (UPC), careglio@ac.upc

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  1. Place for logos of authors’ institutions Optical Access and Metro NetworksModule 3. Switched metro optical networks /Metropolitan Optical Networks (MONs) (??) Davide Careglio, Universitat Politècnica de Catalunya (UPC), careglio@ac.upc.edu Guido Maier, CoreCom, maier@corecom.it Achille Pattavina, Politecnico di Milano, pattavina@elet.polimi.it

  2. Outline • Foreseeing the future • Current standards (and pre-standards) • Optical devices for the OPS deployment • Past researches (current test-beds) • Current researches • Conclusions and future works

  3. Outline • Foreseeing the future • Current standards (and pre-standards) • Optical devices for the OPS deployment • Past researches (current test-beds) • Current researches • Conclusions and future works

  4. Starting from the end… Foreseeing the future

  5. Metro networks Positioning the environment >1 Terabit 1 Terabit-1 Gigabit 1 Gigabit-1 Megabit

  6. Metro networks Requirements

  7. Outline • Foreseeing the future • Current standards (and pre-standards) • Optical devices for the OPS deployment • Past researches (current test-beds) • Current researches • Conclusions and future works

  8. Current standards Sonet/SDH rings

  9. Current standards Sonet/SDH rings • Dual ring for protection

  10. Current standards Gigabit and 10 Gigabit Ethernet • Typical star/tree topology

  11. Current standards Client control frames Shape B Shape C Shape A control filter transit A West East check adjust PHY PHY transit B/C Resilience Packet Ring (RPR) • Bidirectional ring • Distributed MAC protocol • QoS support B B External Ring A A C C Internal Ring D D

  12. Current standards The pioneers • IEEE 802.5 (Token Ring) • Old, electrical solution with just 4 Mbit/s • FDDI • First use of fibre • Great interests at the beginning but dies quickly • IEEE 802.6 (DBDQ) • Distributed mechanism with dual bus topology • Great researchers’ interests but dies quickly • Almost 0 commercial products sold • Some utility for us? • Yes, avoid the same mistakes and adapt the good ideas • e.g. QoS schemes developed for FDDI and DQDB

  13. Cost comparison 1400 20 Gbps 1200 40 Gbps 80 Gbps 1000 800 Relative CAPEX 600 400 200 0 Star Ethernet Sonet/SDH RPR Deployment costs:CAPEX

  14. Cost comparison 900 Star Ethernet 800 700 Sonet/SDH 600 RPR 500 Relative annual OPEX 400 300 200 100 0 20 40 80 20 40 80 20 40 80 Gbps Gbps Gbps Gbps Gbps Gbps Gbps Gbps Gbps Maintenance staff costs Replacement Costs Maintenance costs Operation Deployment costs: OPEX

  15. Pros and cons • Sonet/SDH • High reliability (protection to failures) • Most of current networks are based on SDH (necessity to get revenues) • Currently under the 3G phase with reconfiguration capability • Developed to transport voice through point-to-point circuit • Expensive • Ethernet • Cheap and easy solution • No support for QoS • RPR • Support QoS • High reliability

  16. Pros and cons • All of them require OEO conversion at each node!!! • And hence the electronic part limits the maximum network capacity • Necessity to migrate from just transmitting high-capacity optical signals to effectively switching and managing data in optical domain

  17. Optical packet switching Output interface Input interface Optical switching Header extraction Regeneration Synchronization Payload switching Contention resolution Regeneration Power equalization PAYLOAD HEADER Header processing Switch control logic Header rewriting Who it works…

  18. Optical packet switching Main concepts • OPS generally1 • Lower power consumption than in electronic switches • Lower cost • Easy IP over WDM integration • High throughput, efficiency, flexibility • Finest granularity 1 L. Dittman et al., “The European IST Project DAVID: a viable approach towards Optical Packet Switching”, IEEE JSAC, vol. 21, no. 7, Sep. 2003

  19. Optical packet switching Technology challenges • OPS are now widely accepted • Several prototypes and trial-fields • More than 100 papers during the last leading international conferences (i.e., ECOC and OFC) • Optic is still in its infancy2 • No optical RAMs, (where needed) replaced by Fibre Delay Lines (FDLs) 2 T.S. El-Bawab et al., “Optical packet switching in core networks: between vision and reality”, IEEE Commun. Mag., vol. 40, no. 9, Sep. 2002

  20. Optical packet switching Technology challenges • Need new optical devices3 • Fast switching matrixes (order of ns) • 3R regenerators • Tunable wavelength converters • Optical aggregators, etc. • Optical header processing4 • No optical bit-level processing 3 D. Chiaroni, “Packet switching matrix: a key element for the backbone and the metro”, IEEE JSAC, vol. 21, no. 7, Sep. 2003 4 D. Blumenthal et al., “Optical signal processing for optical packet switching networks”, IEEE Commun. Mag., vol. 41, no. 2, Feb. 2003

  21. OPS-based metro networks Open issues … • Topology • Ring, star, bus, etc. • Architecture • Node, hub, type of transceivers, control and data plane, slotted vs. variable packets, etc. • MAC protocol • Empty slot, request/grant, carrier sense, etc. • QoS provisioning • Classes to be defined, mechanisms to provide them, etc.

  22. OPS-based metro networks … and accepted assumptions • The network must be optically buffer-less • General behaviour • Nodes use electronic buffer to store the packets coming from the access networks • A MAC protocol arbitrates the access of nodes to the shared resources, regulating both time and wavelength dimension • Once a packet is transmitted, the entire source-destination path is buffer-less • Only the control information is electrically converted to be processed

  23. OPS-based metro networks TX … Access network Shared resource MAC RX Schematic node structure

  24. OPS-based metro networks WDM multi-PON WDM multi-ring WDM bus WDM ring WDM star Physical topologies Node WDM link Hub

  25. Outline • Foreseeing the future • Current standards (and pre-standards) • Optical devices for the OPS deployment • Past researches (current test-beds) • Current researches • Conclusions and future works

  26. OPS deployment Availability of optical components

  27. OPS deployment Availability of optical components

  28. OPS deployment Availability of optical components

  29. Outline • Foreseeing the future • Current standards (and pre-standards) • Optical devices for the OPS deployment • Past researches (current test-beds) • Current researches • Conclusions and future works

  30. OPS-based metro networks Past researches • Optical star • AWG-STAR metro network (NTT) • Optical ethernet • DBORN (Alcatel) • WDM ring network • HORNET (Stanford) • RingO (Politecnico di Torino) • Wonder (Politecnico di Torino)

  31. OPS-based metro networks packet node header SOA MUX AWG ln l2 l1 Header analyzer l1 to node 1 ... l2 to node 2 EDFA ln to node n AWG-STAR metro network (NTT) • 2 fixed TX/RX per node: 1 for data, 1 for control • l-conversion at the central node to communicate any arbitrary pair of node • Control header determine the target l

  32. OPS-based metro networks packet in lt EDFA local drop local add packet in lr 2x2 switch protection from MAN to MAN node Hub lr lr lt lt Dual Bus Optical Ring Network (Alcatel) • Unidirectional ring • Spectral separation of upstream and downstream flows from/toward the Hub • Optical CSMA/CD MAC protocol

  33. OPS-based metro networks Slot Manager Smart Drop Smart Add from MAN to MAN sub-carrier tone packet empty slot sub-carrier receiver burst-mode packet receiver node fast tunable packet transmitter address recovery packet switch slot detector local drop local add Hornet (Stanford) • Slotted unidirectional ring • Optical CSMA/CS MAC protocol • Subcarrier header l1 l1 l2 l2 l3 l3

  34. OPS-based metro networks node node i i l l tunable tunable fixed fixed i i TX TX RX RX l l k k node node k k packet packet from from to to on on l l i i k k k k l l m m packet packet l l j j from from to to m m j j node node j j on on l l j j RingO (Politecnico di Torino) • Slotted, unidirectional ring • Array of TX to simulate tuneable TX • CSMA MAC protocol • li to transmit to node i

  35. OPS-based metro networks Wonder (Politecnico di Torino) • Dual bus • Master node configures the ls

  36. Outline • Foreseeing the future • Current standards (and pre-standards) • Optical devices for OPS deployment • Past researches (current test-beds) • Current researches • Conclusions and future works D. Careglio PhD , June 8, 2005

  37. OPS-based metro networks Current researches: composite topologies • PSC||AWG network • RingoStar network • Multi-PON network • Multi-ring network

  38. OPS-based metro networks PSC||AWG network • Mainly for protection task

  39. OPS-based metro networks RingoStar network • Optical ring, electrically interconnected through an optical star

  40. OPS-based metro networks WAN node hub WAN MAN node router switches MAN Multi-PON Multi-ring Multi-ring and multi-PON network

  41. OPS-based metro networks QoS in the standards • Electrical metro networks • Optical metro networks • No standard, only prototypes (DBORN, Hornet, RingO, etc.)

  42. OPS-based metro networks QoS provisioning: Type of services • Guaranteed service • Real-time applications • Absolute priority over the other types of services • Reservation of network resources • Priority or differentiated service • Some traffic is treated better than the rest (faster handling, more bandwidth on average, lower loss rate on average). • Statistical preference, not a hard and fast guarantee • Best-effort service • Basic connectivity with no requirements • Fairness mechanism guarantees fair share of bandwidth utilisation

  43. OPS-based metro networks WAN node hub WAN MAN node router switches MAN Multi-PON Multi-ring Multi-ring and multi-PON networks

  44. Multi-PON WDM networks Network Controller node EDFA N × N AWG Wavelength Converters Arrays data data control control • Architecture8 • MAC protocol9 • Request-based • Scheduling at NC • Greedy9 • Frame-based10 • QoS mechanism9 • GS • HP and BE 8 N. Caponio et al., “Single layer optical platform based on WDM/TDM multiple access …”, ETT, vol. 11, no. 1, Jan. 20009 A. Bianco et al., “Network controller design for SONATA”, IEEE JSAC, vol. 18, no. 10, Oct. 200010 A. Bianco et al., “Frame-based matching algorithms for input-queued switches”, IEEE HPSR 2002, Kobe, Japan, May 2002

  45. Multi-PON WDM networks PON PON PON PON PON PON PWRN Architecture • Communication between PONs: WDM • PWRN selects the output according to the input wavelength

  46. Multi-PON WDM networks PON PON PON PON PWRN l conv Architecture • Additional capacity: l-converters • When the direct wavelength between PONs is not enough, the pool of wavelength converters provides additional capacity

  47. Multi-PON WDM networks 1 slot (1 ms) DATA-frame/slot structure optical packets 1 frame = 100 - 1000 slots (0.1 - 1 ms) Architecture • DATA-Frame format • The time on each wavelength is divided into slots which are organized into frames

  48. Multi-PON WDM networks NC PON PON PON PON PWRN Architecture • Communication between the terminals and the Network Controller • At least one dedicated wavelength per PON • Static TDMA See Module-2 for description of Multi-PON

  49. Multi-ring WDM networks Architecture • Architecture14 • MAC protocol15 • Optical slotted rings • Scheduling at NC15 • Measurement based • QoS mechanism16 • GS • HP and BE 14 L. Dittman et al., “The IST project DAVID: a viable approach towards optical packet switching”, IEEE JSAC, vol. 21, no. 9, Sep. 200315 A. Bianco et al., “Measurement-based resource allocation for interconnected WDM rings”, PNC, vol. 5, no. 1, Jan. 200316 J.D. Angelopoulos et al., “A QoS sensitive MAC for slotted WDM metro ring”, ONDM 2002, Feb. 2002 D. Careglio PhD 16013, June 8, 2005

  50. Multi-ring WDM architecture 1 slot (1 ms) DATA-frame/slot structure optical packets 1 frame = 100 - 1000 slots (0.1 - 1 ms) MAC protocol • DATA-Frame format • The time on each wavelength is divided into slots which are organized into frames D. Careglio PhD 16013, June 8, 2005