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PowerPoint Presentation - TNC 2004



      D. Simeonidou, R. Nejabati & M. J. O’Mahony
                   University of Essex
          Wivenhoe Park, Colchester CO4 3SQ, UK

                A. Tzanakaki & I. Tomkos
          Athens Information Technology Center
Markopoulou Ave., PO. BOX 68, 190 02 Peania, Athens, Greece
    Optical Network Infrastructures for Grid Computing


• Global Grid scenario based on optical networks
• Appropriate switching paradigm
   •Optical Burst Switching
• The functional blocks required:
   •Core Router
   •Edge router functionality
       •Grid User Network Interface
       •Grid Resource Network Interface
• Challenges and solutions in terms of functionality and
    Optical Network Infrastructures for Grid Computing

    Global Computing

• Local computational resources cannot keep up
  with the demands generated by some
  – high-volume (long- or short-lived) jobs with high
    demands for processing and storage
  – large number of medium/small jobs requesting
    distributed resources
• Distributed computing using the concept of a
  global computational Grid is proposed
  – It is not a new paradigm but until recently networks
    could not support the features and capabilities to offer
    efficient use of remote resources
        Optical Network Infrastructures for Grid Computing

         Infrastructures for Grids

• The Grid application characteristics and requirements influence the
  choice of a suitable network infrastructure
    – transport and switching format
    – control signalling and management
    – physical layer technology
•   Grid applications differ with respect to the following characteristics:
    –   granularity of traffic flows
    –   required data transaction bandwidth
    –   QoS and acceptable delay
    –   throughput and packet loss
    –   storage capacity
    – processing power etc.
        Optical Network Infrastructures for Grid Computing      


• Particle physics large international collaborations and experiments involve
  enormous amounts of data requiring processing and analysis of Petabytes
  per year
• Very Long Baseline Interferometry (VLBI) used by radio astronomers for
  detailed images and experiments bring data from distributed instruments to
  a central point to correlate the signals from individual telescopes
• High Performance Computing and Visualization focuses on adapting and
  developing parallel codes for execution on parallel processors. Remote
  visualisation of terabytes of data requiring high bandwidth links ~ 1 Gbit/s or
  hundreds Mbit/s that increase with the number of remote observers
• E-Health, e.g. Mammography introduces increased capacity requirements
  due to size and quantity of scan images
    – For 100 patients to be screened remotely, the network would have to carry 1.2GB
      of data every 30 seconds
    – For this type of application speed of data transfer is important
         Optical Network Infrastructures for Grid Computing         

          Grid Features and Characteristics

• Suitable network infrastructures are required to offer very different features
  compared to traditional telecommunications infrastructures
• In telecommunications networks when traffic demands arise there is always a
  predetermined pair of two discrete points that need to communicate
• In Grid networks particular end-users/applications require to access available
  network resources for processing/storage and need to identify their availability
    – Only the source is predetermined, while the destination has to be discovered and
      identified using intelligent mechanisms supporting advanced signalling schemes
         •Self organization

• In Grids bidirectionality and symmetry of connections unlike
  telecommunications networks is not necessary. The two directions are
  generally required, one to discover and access the network resources and
  submit the job and the other to extract the results and deliver them to the user
    – However, the two directions can be decoupled and set-up independently
     Optical Network Infrastructures for Grid Computing

      Grid Networks I

• The common requirements in this type of networks are
  summarised as follows:
   – High capacity for bulk data transfer, low cost bandwidth on
     demand for short or long periods of time between discrete points
     across the network (i.e. point and click provisioning)
   – Service granularity at the wavelength and sub-wavelength level
   – Multicasting capabilities
   – Hardware flexibility to support wide range of different distributed
   – Resilience to different layers, from the application layer to the
     wavelength layer
   – Network security
   – Ability to provide management and control of distributed network
     resources to the user/application
       Optical Network Infrastructures for Grid Computing   

       Grid Networks II

• In these networks resource request, discovery and allocation are
  performed initially when a processing requirement arises. There is
  no bandwidth reservation in advance - core routers decide on the fly
  where to forward the data
• Core routers require some application and network-level awareness
  to configure the resources best suited for the task. This can be
  achieved utilising two types of information:
    – The data needs to be accompanied by information on the nature of the
      job e.g. estimated computational and storage capacity, QoS related
      information (feed-forward information)
    – Information about the status of the network needs to be included. The
      grid resources provide periodically information about their status and
      availability e.g. free storage capacity, computational load, and network
      resources (feed-back information)
Optical Network Infrastructures for Grid Computing

Optical Network Infrastructure for Grids I
      Optical Network Infrastructures for Grid Computing

      Optical Network Infrastructure for Grids II

• Distributed computing becomes a realistic solution with
  the recent advancements of optical networks based on
  wavelength division multiplexing (WDM)
• Can support a distributed control plane to allow
  control/access and even ownership of network resources
  by the users/applications in contrast to traditional
  telecommunications networks
• Set-up, control and tear-down of end-to-end lightpaths
  across multiple domains can be provided through the
  use of
   – existing protocols like Generalised Multiprotocol Label Switching
   – new protocols such as the Optical Border Gateway Protocol
     Optical Network Infrastructures for Grid Computing

     Switching Paradigm for Grids

• Optical burst switching (OBS) supports multi-service
  traffic, offering high granularity (sub-wavelength), high
  spectral efficiency as well as bandwidth and low latency
• Offers transport for highly demanding Grid applications
  and all-optical data transmission with ultra-fast
  user/application-initiated light path setup
• Accommodates bursty traffic with improved network
  economics and provide convergence of electronic and
  optical technologies
• Enables control and management integration and
  simplification offering a distributed control plane
  supporting advanced signaling schemes
       Optical Network Infrastructures for Grid Computing   

        Optical Burst Switching

• OBS assumes burst aggregation at the edge of the network with
  burst lengths from 10s of kB to several MB
• OBS is based on the asynchronous operation mode with variable
  length optical bursts depending on the nature of the application
• The control information is out of band and transmitted prior to the
    – It is at a lower data-rate than the data burst
    – It is processed independently of the data burst mostly in the electronic
    – The value of the time offset may be used for offering QoS differentiation
        •Resulting in reduction or elimination of optical buffering

• The data burst is transparently switched and routed through the
  network without the requirement of any optoelectronic conversion
Optical Network Infrastructures for Grid Computing

OBS Network Scenario I
    Optical Network Infrastructures for Grid Computing    

    OBS Network Scenario I

• OBS can support a set of important requirements for Grid users
  listed below:
    • Application initiated lightpath set-up
    • Resource discovery and allocation mechanisms
    • Delivery of jobs to the available resources
    • Delivery of processing results (if there are any) to the user
    • Dedicated network feedback mechanisms to user
    • Providing necessary flexibility in architectures to support both carrier
      -owned and user-owned networks
    • Supporting the requirements for both physical and application layer
    • Light-trees & Optical Multicasting
• OBS can deal with a wide variety of applications and
  accommodate small, medium and large jobs to support the
  application requirements in terms of duration, latency etc
• OBS does not require resource reservation and does not impose
  any strict requirement for symmetry in the two directions of
     Optical Network Infrastructures for Grid Computing            

     Optical Multicasting

•   Optical multicasting is the concept of 1:N light-trees
•   A light-tree is a clear channel originating at a given source node having multiple
    destination nodes i.e. is a point-to-multipoint channel. The use of light-trees can
    significantly reduce the number of hops (or lightpaths) that the data has to
    traverse and therefore significantly improve the throughput of the network.
•   Optical multicasting can be applied in OBS network scenarios for grid
    applications to improve network performance and efficiency. In general avoiding
    multicasting at a higher layer:
     •reduces requirements for optoelectronic conversions
     •limits the need for store-and-forward functions
     •enhances the virtual connectivity of the network
        Optical Network Infrastructures for Grid Computing                                         

         Core Routers - Optical Burst


                         1                                                                  1
                                 .      Input     .                    .     Output     .
         N input ports           .   Processing   .                    .                .   N output ports
                                 .                .                    .   Processing   .
                         N                                                                  N

                                                      Electronic Control

                                                       Routing Table

Input processing:             power equalisation, activates control
Switching:                    provides path between switch input port and required output port
Output processing:           optical burst conditioning
Buffering:                   not always required, stores bursts when contention arises
Routing table:               stores routing information
Control:                     control switch fabric, with info from control packet and routing table
        Optical Network Infrastructures for Grid Computing 

        Optical Burst Switches I

• An optical burst switch architecture and the appropriate switching
  technology should offer advanced features such as
    • dynamic reconfiguration with high switching speed (~ ms)
    •   strictly non-blocking connectivity between input and output ports
    •   multicasting capabilities
    •   capability to address contention issues and QoS differentiation
    •   scalability
    •   upgradeability
    •   minimum performance degradation for all paths
• To resolve contention in the optical burst switch the following options
  and their combination can be used:
    • Wavelength dimension: wavelength conversion
    • Space dimension: deflection routing, in which optical bursts are
      diverted through a different route to their destination nodes e.g. hot
      potato scheme
    • Time dimension: optical or electronic buffering
        Optical Network Infrastructures for Grid Computing         

        Optical Burst Switches II

• Multicasting operation can be achieved using passive splitters and couplers
• Alternative solutions may be also attractive in terms of performance,
  functionality and scalability such as:
    •    multicasting switches with fast response
    •    wavelength converters supporting multicasting capabilities
    •    other optical/optoelectronic devices and subsystems offering similar features
   Optical Network Infrastructures for Grid Computing

     Grid User-Network Interface (GUNI) I

The Grid edge device with GUNI functionality is responsible for:
    • User job pre-processing and transmission entity construction
       •Job classification, aggregation (grooming)
       •Optical burst assembly
       •Flexible bandwidth allocation
    • Pre-processing the results coming back from Grid resources
       •Send back results to the users
    • Anycasting the optical burst to the core nodes
       •λ-selection for anycast
    • User authentication and security check, job acceptance or
    • Grid service billing and accounting
    • Fault detection, protection and restoration
Optical Network Infrastructures for Grid Computing

Grid User-Network Interface (GUNI) II
        Optical Network Infrastructures for Grid Computing          

        Grid Resource-Network Interface (GRNI)

• In GRNI is responsible for:
    • Pre-processing of the incoming optical bursts
         • Optical burst segregation
         • Job submission to local Gird resources
    •   Advertising state of the local resources:
         • Broadcasting of the available processing/storage capacity to the optical network
    • Sending back results of a completed job
         • Optical burst assembly
         • Bandwidth allocation and light-path setup
          Optical Network Infrastructures for Grid Computing            


•   A variety of applications and the requirements they imposed on global Grid networks
    have been discussed
•   A novel Grid network scenario based on optical infrastructures has been proposed
•   The solution is based on the optical burst switching paradigm to fulfil the Grid
    application specific traffic requirements and offer efficient sharing of network
•   The fundamental functional blocks needed are the Core Router, the Grid User
    Network Interface and the Grid Resource Network Interface
•   The core router based on optical technologies is able to support routing of the optical
    bursts on the fly and provide advanced features such as optical multicasting
•   The optical GUNI is able to support fast and dynamic burst assembly and wavelength
    allocation per burst
•   The GRNI provides simple signalling between the local resources and the optical
    network while it offers a data transport mechanism between Grid resources and the
    optical network
Thank you!

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