From GMPLS to OpenFlow Control & Monitoring of Optical Networks

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From GMPLS to OpenFlow Control & Monitoring of Optical Networks, Piero Castoldi.
Acknowledgements (people): A.Giorgetti, F. Cugini, F. Paolucci, B. Martini, N. Sambo, M. Gharbauoi, A. Sgambelluri, D. Adami.
Workshop “(G)MPLS and OpenFlow: Interworking, Integrating, or Replacing?”
Dublin, May 7 2013

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From GMPLS to OpenFlow Control & Monitoring of Optical Networks

  1. 1. From GMPLS to OpenFlow Control&Monitoring of Optical Networks Piero Castoldi Acknowledgements (people): A.Giorgetti, F. Cugini, F. Paolucci, B. Martini, N. Sambo, M. Gharbauoi, A. Sgambelluri, D. Adami Acknowledgements (projects): STRONGEST, IDEALIST, OFELIA Workshop “(G)MPLS and OpenFlow: Interworking, Integrating, or Replacing?” Dublin, May 7 2013
  2. 2. Outline • Introduction on optical network management and control • Emergence of Software Defined Networks • A couple of specific implementations for flexible optical networks – Control of Optical Network through OpenFlow – Monitoring Experiments of Optical Networks through OpenFlow © 2013 Scuola Superiore Sant’Anna
  3. 3. There was the centralized management of ON .. Static NMS 1 • Management plane: coordination of network elements to configure, analyze and monitor network resources to guarantee network operation “FCAPS” functions – Fault management: detecting failures and isolating failed component – Configuration management: managing orderly network changes e.g. equipment addition/removal – Accounting management: billing and developing component lifetime histories – Performance management: monitoring and managing various network performance metrics – Security management: user authentication, control access to network elements, user data protection etc. © 2013 Scuola Superiore Sant’Anna
  4. 4. From centralized to distributed GMPLS network control .. 2 Static NMS GMPLS controller GMPLS controller GMPLS controller GMPLS controller – Path computation – Connection establishment and release – Fault recovery 1 • • GMPLS CP aimed at enforcing automated connection management Routing – Open Shortest Path First with Traffic Engineering extensions, OSPF-TE • Signaling – Resource Reservation Protocol with Traffic Engineering extensions, RSVP-TE • Link Management – Link Management Protocol LMP • Path Computation – Distributed: locally performed at the source node that receives the connection request © 2013 Scuola Superiore Sant’Anna
  5. 5. Some functions returned centralized .. PCE 2 Static NMS GMPLS controller GMPLS controller GMPLS controller GMPLS controller GMPLS controller GMPLS controller GMPLS controller GMPLS controller 1 3 • Path Computation – Centralized: performed in a Path Computation Element communicating with the connection source node using the Path Computation Element Protocol (PCEP) • PCE maintains a TED – Updated by means of the LSA flooded by the running OSPF-TE routing protocol – Updated by means of direct communication with the network nodes • Stateful PCE – Besides the TED, also information about the previously computed path are utilized during path computation • Stateless PCE – Only the information stored in the TED are used for path computation © 2013 Scuola Superiore Sant’Anna
  6. 6. Impairment awareness in GMPLS CP GMPLS lightweight extensions to RSVP-TE signaling protocol encompass physical impairment awareness degradation in alloptical networks: • Encompassing an OSNR model that accounts for physical attenuation, Polarization Mode Dispersion (PMD), Chromatic Dispersion (CD) and Self Phase Modulation (SPM), to identify the best wavelength assignment. • Encompassing crosstalk effect via the Crosstalk Vector (XV) object to identify the preferred wavelengths, e.g. the ones with minimum added crosstalk. • Encompassing the use of shared regenerators thanks in a distributed way (object accounting for already used regenerators and explicit flag for regeneration) © 2013 Scuola Superiore Sant’Anna
  7. 7. Emergence of Software Defined Networks © 2013 Scuola Superiore Sant’Anna 7
  8. 8. Software Defined Networking Network Services APP2 APP1 (e.g., Access Control) (e.g.,Protected path) APP3 (e.g., network defrag) • Software Defined Network Controller(s) (e.g. NOX) NMS Adap SNMP OpenFlow EM Intf SNMP OF Intf NMS-based network GMPLSbased network OF-based network Legacy Network devices • • • Software-defined networking (SDN) emerged as a new paradigm that decouples physical network implementation from network control logic. Data plane functions (forwarding) reside within network elements (switches, routers) Control plane functions (routing, signaling) are moved to a separate dedicated controller Network Services are realized through dedicated APPlications running within the Controller OS Network © 2013 Scuola Superiore Sant’Anna
  9. 9. OpenFlow is SDN but not viceversa • OF is currently the suggested interface by ONF between the controller and the OF-capable network device. • OF is under consideration in several scenarios such as: carrier grade Ethernet, and optical transport networks. • The controller manages the switching elements (i.e OpenFlow switches) by programming their flow tables. © 2013 Scuola Superiore Sant’Anna
  10. 10. The return of centralized control of optical networks PCE 2 Static NMS GMPLS controller GMPLS controller GMPLS controller GMPLS controller GMPLS controller GMPLS controller GMPLS controller OF-GMPLS cooperation OpenFlow controller GMPLS controller GMPLS controller GMPLS controller GMPLS controller GMPLS controller 1 3 4 GMPLS replacement by OF • OpenFlow is being adapted for controlling optical networks • Key idea: OpenFlow controller perform path computation, node configuration, lightpath maintenance and monitoring functions through unique, open, standard protocol (OPEX reduction with respect to distributed GMPLS suite) • E.g In flexible optical networks, additional parameters can be considered for lightpath provisioning: modulation format, FEC, type of channel, allocated spectrum, transponder/receiver dynamic configuration OpenFlow controller 5 © 2013 Scuola Superiore Sant’Anna
  11. 11. Network Facilities at SSSA/CNIT Pisa SDN/OF controller (NOX, Flowvisor) GMPLS control plane Middleware (Ofelia control framework) ROADM Ericsson MHL3000 1 ch add-drop @ 10Gb/s DWDM GMPLS GE/FE Data Center • • • • Juniper M7i/M10 routers Juniper EX3200/2200 switches Cisco 7200 VXR router Emulated OpenFlow switch GE/FE OF controller CNIT-Pisa Ofelia island OpenFlow Ethernet ring © 2013 Scuola Superiore Sant’Anna
  12. 12. Control of Optical networks through OpenFlow 12 © 2013 Scuola Superiore Sant’Anna
  13. 13. OF-GMPLS lightpath setup (cooperation mode) • Source: request to OpenFlow controller • OpenFlow controller: routing TED update: previously routed requests OpenFlow controller: reply to source • Source: RSVP-TE Path to destination OpenFlow controller GMPLS controller GMPLS controller GMPLS controller GMPLS controller Explicit Route Object Label Set Object Suggested Label • Destination: wavelength assignment • Destination: RSVP-TE Resv to source Resource reservation OXC cross connections • Lightpath established © 2013 Scuola Superiore Sant’Anna
  14. 14. OF lightpath setup (replacement mode) • • OpenFlow controller Source: request to OpenFlow controller OpenFlow controller: routing TED updated: previously routed requests • • Controller: flow configuration at each OXC Each OXC: flow configuration Resource reservation • OpenFlow controller: reply to source Controller Timer OF-timer: • Wait timer expiration without errors OF-ack: • Wait the last ack • Data Lightpath established © 2013 Scuola Superiore Sant’Anna
  15. 15. OF-based flexi lightpath provisioning: OF-ACK scheme implementation • Switch-controller OF session over TCP • Lightpath setup needs node configuration confirmation • Provisioning Request-Reply maintained (PCEP-like) • Fast parallel node configuration • Errors handling: no-path, failed flow_mod OF Controller Messages: • lightpath_in (lightpath request) • flow_mod (set flow entry) • flow_ack (ack entry) • lightpath_out (lightpath setup outcome) OU H_ AT TP OFPT_FLOW_MOD IGH T OFPT_FLOW_MOD T_L OFPT_FLOW_MOD FP O P OF T IGH T_L TH PA _IN © 2013 Scuola Superiore Sant’Anna
  16. 16. OpenFlow controller implementation • • • • Based on the PCE engine, path_solver + Controller_handler modules Performs path computation: route, spectrum assignment, modulation format and FEC assignment, impairment validation. Different IV and RSA strategies available (joint, IV+RSA) Performs node configuration (centralized signaling): Cross-connections, WSS spectrum shaping, TX/RX fine configuration, flexible submodules on/off Performs monitoring (statistics collection and analysis) and feedback-based optimization Optical channel QoT parameters monitoring Degraded QoT triggers analysis (fault localization through cross-correlation) and decisions (e.g., lightpath re-routing, dynamic modulation format adaptation) Path solver OFTED IV models Controller Handler OF interface OF sessions © 2013 Scuola Superiore Sant’Anna
  17. 17. OpenFlow Switch implementation • Port configuration (switch abstraction), state and statistics • Flow table stores active entries (installed flows) • Device interface maps configuration commands into hardware-specific commands Controller session OF interface Port config, state, stats OF switch handler Flow table Device interface Switch hardware © 2013 Scuola Superiore Sant’Anna
  18. 18. Flexi Optical ROADM/Switch abstraction •Design relies on different port types (fixed or flexible, IN_PORT [ ] depending on the switch architecture) and flexible transponder/receiver •Flow entry format: transit •Intermediate hop: [in_port (transit), out_port (transit) ,assigned_ spectrum] •Src: [in_port (add), out_port (transit), assigned_spectrum, add OCh_spec] •Dst: [in_port (transit), out_port (drop), assigned_spectrum, OCh_spec] •Spectrum collision check performed at each out_port TX OUT_PORT [ ] transit drop RX © 2013 Scuola Superiore Sant’Anna
  19. 19. Monitoring Experiments of Optical Networks through OpenFlow 19 © 2013 Scuola Superiore Sant’Anna
  20. 20. Monitoring in OpenFlow-based networks • OF-Controller responsible to compute and configure flow tables (i.e., forwarding tables) on OpenFlow switches • Statistics are typically exchanged for manageability and monitoring functions. Symmetric messages (OFPT_STATS_REQUEST and OFTP_STATS_REPLY) • Port status info may be exchanged to notify link failures. • New types of statistics are required in flexi-grid networks, e.g.: Quality of Transmission (QoT) statistics OAM statistics • OF-Controller may utilize statistics information to improve monitoring, fault notification, localization, etc. © 2013 Scuola Superiore Sant’Anna
  21. 21. Flexi optical network and monitoring enhancements •BER and MSE statistics at coherent receiver (PM-16QAM, PM-QPSK) •OSNR, non-linear parameters, frequency offsets, equalizer coefficients (CD and PMD estimation) © 2013 Scuola Superiore Sant’Anna
  22. 22. OpenFlow monitoring statistics • For each lightpath monitoring parameter, specific field within OFPT_STATS_PORT_LP structure is defined and managed in switches • OF-Controller performs periodic requests at configurable time interval (DEFAULT_POLL_PORT_PERIOD, e.g. 1 min.) Polling rate may change according to network conditions • • OF-Controller enhanced with new IN_PATH vector storing also statistics. Each activated lightpath (unique DPID) includes IN_PATH including traversed links ->correlations among statistics and actual traversed resources are possible © 2013 Scuola Superiore Sant’Anna
  23. 23. Experimental demonstration (1) BER statistics collected by OF-Controller L1 L4 Warning BER threshold Critical BER threshold L2 L3 EDFA • 4 lightpaths activated (L1-L4), 200Gb/s 16-QAM, coherent detection • BER monitoring updated every 1 min. • QoT degradation on link 3-4, time increasing • Warning and Critical thresholds set at OF-Controller, polling rate raises to 1s • Correlations : statistics and traversed link info stored within IN_PATH -> Link 3-4 identified as possible degradation source © 2013 Scuola Superiore Sant’Anna
  24. 24. Experimental demonstration 2 Capture of OpenFlow messages Modified OpenFlow Stats Reply message • Bit Error Rate (BER) field enclosing current BER measurement at port PORT_NUMBER • Further actions applied by OF-Controller upon new requests: 1. Stronger modulation format while maintaining bit-rate (QPSK, 200G) 2. 2 LSPs halving the bit-rate (QPSK, 100G) 3. Different route (e.g., 3-2-1 with respect to 3-4-1) © 2013 Scuola Superiore Sant’Anna
  25. 25. Research directions and open points • OF controller and switch implementation extensions • Global re-optimization (e.g., OF-driven PushPull technique) • Protection and fast restoration solutions • Multicast (P2MP) support • OF multi-domain, multi-layer • SDN alternative or complementary to distributed GMPLS for reliability? • Recognized GMPLS advantage: efficient fast recovery • Potential SDN drawbacks: scalability issues, controller communication failure issues, complex disaster recovery • Pure/mixed architectures to be considered and evaluated (e.g., pure OF, OF+ basic RSVP-TE, OF +RSVP-TE +LMP) • OpenFlow controller and PCE: which relationship? © 2013 Scuola Superiore Sant’Anna
  26. 26. Recent Related recent publications • • • A.Giorgetti, F. Cugini, F. Paolucci, P. Castoldi, “OpenFlow and PCE architectures in Wavelength Switched Optical Networks”, ONDM 2012 F. Paolucci, F. Cugini, N. Hussain, F. Fresi, L. Potì, “OpenFlow-based Flexible Optical Networks with Enhanced Monitoring Functionalities”, ECOC 2012 N. Sambo, F. Paolucci, F. Cugini, M. Secondini, L. Potì, G. Berrettini, G. Meloni, F. Fresi, G. Bottari, P. Castoldi, “Software Defined Code-rate-adaptive Terabit/s based on time-frequency Packing”, submitted to OFC/NFOEC 2013 © 2013 Scuola Superiore Sant’Anna
  27. 27. thank you! E-mail: castoldi@sssup.it © 2013 Scuola Superiore Sant’Anna

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