QRON QoS-Aware Routing in Overlay Networks by yantingting

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									QRON: QoS-Aware Routing in
Overlay Networks

              Zhi Li, Prasant Mohapatra
  IEEE JOURNAL ON SELECTED AREAS IN
     COMMUNICATIONS, VOL. 22, NO. 1,
                          JANUARY 2004




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                Outline

   Introduction
   Overlay Service Network
   QoS-Aware Routing in Overlay
    Networks
   Performance Evaluation
   Related Work
   Conclusion


                                   2
                     Introduction
   Incorporate QoS in the best-effort service
    model of Internet
      Network-level QoS provision
             IntServ DiffServ : far from being deployed
             Require the network infrastructure
        Alternative approach for QoS provisioning are
         mechanism in the application layer while
         retaining the best-effort network layer
             Overlay network -- an effective way to support
                New application

                New protocol

                Without any changes in the underlying
                 network layer



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                      Introduction
   Propose to develop a general overlay
    service network (OSN)
       Shared by a variety of applications
       Overlay brokers (OBs)
          Strategically placed across the Internet
           domains
          Provide a unified platform to serve several
           overlay applications
       At each OB
          An overlay service layer (OSL) is
               implemented between the transport layer and
                application layer
               Common functions




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                    Introduction
   QoS-aware routing protocols for overlay
    network (QRON)
       Runs at the OSL among the OBs
       Search QoS-satisfied overlay path forming
        overlay networks for upper layer QoS-sensitive
        overlay applications
       Balance overlay traffic load on OBs and overlay
        links
       Better than designing QoS-aware routing
        protocol for each specific overlay applications



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                Overlay service network
                 Overlay Broker (OB)
   OBs
       Placed in the Internet by a third party ( overlay
        service prodiver(OSP))
       Provide generic overlay service to support to
        overlay applications
       The OBs subscribe high bandwidth
       The OBs of one domain know the address of the
        OBs of the neighboring domains
             During deployment
             through exchange of messages
       The OBs are also responsible for encapsulation and
        decapsulation of the outgoing and incoming
        packets of the overlay network, respectively.



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Overlay service network
 Overlay Broker (OB)




                          7
Overlay service network
 Overlay Broker (OB)




                          8
              Overlay service network
             Functional Modules of OSN

   Topology Discovery
            If two OBs are within the same AS
                 An overlay link connecting the two OBs
            An interdomain link between two domains
                 An overlay link in the overlay topology
            More than one interdomain links connect two
             Ases
                 The overlay links correspond to the number of
                  such links
       The OBs within the same domain can form full
        mesh connecting each other
       The OSN interconnecting multiple domain is
        not a full mesh topology


                                                                  9
 Overlay service network
Functional Modules of OSN




                            10
           Overlay service network
          Functional Modules of OSN
   Performance measurements of
    overlay links
       An overlay link is usually composed of multiple
        physical links
       Nonoverlay traffic would be using the same
        physical links
       Overlay function work on top of the
        transportation layer
           The OB cannot control or manage the IP-layer
            resources
       To obtain the performance of an overlay link
           Rely on measurements
           Active send traffic between two OBs




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          Overlay service network
         Functional Modules of OSN

   Resource Allocation
       The utility-based resource allocation method
        proposed in Opus
       Use model and the SLAs to meet the goal
          Each customer is associated with a value
           based on the service level agreement (SLA)
          The goal : maximize the global utility (value)
          Model to predict the different allocation
           methods




                                                       12
              Overlay service network
             Functional Modules of OSN
   Service Provisionig
       The identity of the OBs are well known or can
        be obtained from a directory service
       When a new customer want to subscribe
        overlay services from the OSN
          First contacts an OB (access OB)
          Based on the service type to determine
                 the topology that would connect the required OBs
                 The QoS requirement of the overlay path
                 The computing capacity requirement of the
                  intermediate OBs
            Then using the QoS-aware routing algorithm
             to find all the necessary paths which compose
             the application-specific overlay


                                                                 13
                       QRON
                 Problem Description
   Overlay path searching process is different from
    the problem of network-level QoS routing
       OB cannot directly access the available resources in
        the overlay path
            Only rely on the measurement techniques
       Nonoverlay traffic
       The processing capacities of the OBs need to be
        considered while selecting an overlay path
   The problem
       How to select QoS-aware overlay paths
       Route data based the QoS requirements
       The dynamic overlay link quality



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                            QRON
                           Basic Idea
   The following approach
    1)While select the overlay links
        tries to balance the traffic among the overlay links
            and OBs
           Ensure the overlay traffic will be resilient to the
            background nonoverlay traffic
           Less impact on the existing overlay traffic
    2)Source-based routing protocol
        Hierarchical architecture
                 Scalable
                 Control message
    3)Nonoverlay traffic may increase suddenly
           Backup overlay paths
           Previous hop OBs to search for backup paths



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                     QRON
                  Path Selection

   Modified Shortest-Distance Path
    (MSDP)
       Based on Shortest-distance path -- to
        guarantee the packets travel along the
        lightest path
           Rij the available bandwidth on link Lij

           The weight of the link is defined as
            1/Rij




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                       QRON
                    Path Selection

   MSDP
       The weight or the distance function of
        the overlay link(i,j)



       If an overlay path passes through the
        OB1,….,Obn
            The weight of the path is defined as



                                                    17
                        QRON
                     Path Selection
   Proportional Bandwidth Shortest Path (PBSP)
       Include the influence of all the resource components
       Balance the load with respect to the combined
        influence of all the resource components
       Based on the following criteria
          Link(i,j)'s capacity Bij > link(m,n)'s Bmn
          The probability of choosing link(i,j) Pij > Pmn

          If (Bij-RB)/Bij > (Bmn-RB)/Bmn

           Then Bij>Bmn and Pij>Pmn
           Define Pij as (Bij-RB)/Bij
           The weight of the link is defined as
          ((Bij)/(Bij-RB))




                                                             18
                       QRON
                    Path Selection

   PBSP
       The weight or the distance function of
        the overlay link(i,j)



       If an overlay path passes through the
        OB1,….,Obn
            The weight of the path is defined as



                                                    19
                     QRON
            Hierarchical Organization
   Our approach of clustering is based on
    the following guidelines
       The OBs within the same AS are clustered
        together
       Physically closer OBs/clusters are clustered
        together
       If two OBs/clusters have multiple overlay links
        connecting ,they are clustered together
   Each OB periodically broadcast its
    computation capacity and the attached
    overlay link capacities information
       Only in its own cluster



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         QRON
Hierarchical Organization




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         QRON
Hierarchical Organization




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         QRON
Hierarchical Organization




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         QRON
Hierarchical Organization




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         QRON
Hierarchical Organization




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                        QRON
               Hierarchical Organization




Composed of virtual
   overlay links




                          Composed of virtual
                             overlay links
                                                27
          Performance Evaluation
   Evaluate the following performance of
    MSDP and PBSP
       Balancing overlay traffic among the overlay
        links.
       Balancing the overlay traffic overhead among
        the OBs.
       Finding and providing QoS-satisfied paths
        connecting the source OBs and destination OBs.
       Overlay path penalty compared with IP-layer
        routing protocols.



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            Performance Evaluation
                simulation setup

   GT-ITM-Generate the network
    topology
       1000 nodes that are evenly
        distributed across 100 domains
       An OB in each domain
       Each of the clusters in the hierarchy
        has an average of ten
        members(subclusters)


                                                29
             Performance Evaluation
                 simulation setup
   To simulate different dynamic network
    situations
       Scenario 1: 80% of the overlay routing requests'
        source and destination pairs are from 50% OBs,
        while others are uniformly distributed among all
        the other OBs.
       Scenario 2: 80% of the overlay routing requests'
        source and destination pairs are from 25% OBs,
        while others are uniformly distributed among all
        the other OBs.
   In the Internet
       most of the interdomain traffic is concentrated
        across a smaller subset of ASes.


                                                          30
       Performance Evaluation
  simulation results and discussions

1)QoS-Satisfaction Rate (QSR)
     The unbalanced distribution of Internet
      traffic
     Shortest-path-based routing protocol
      cannot provide a QoS-satisfied path
     QSR is defined as




                                            31
     Performance Evaluation
simulation results and discussions




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     Performance Evaluation
simulation results and discussions




                                     33
       Performance Evaluation
  simulation results and discussions

2)Link Stress Penalty
     QoS-satisfied overlay paths are usually
      longer than the corresponding IP-layer
      least-cost paths
     Link stress to evaluate the penalty
        The number of IP-layer hops by QoS/The
         number of links by the IP-layer path
        Lower link stress penalty is better




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     Performance Evaluation
simulation results and discussions




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     Performance Evaluation
simulation results and discussions




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        Performance Evaluation
   simulation results and discussions

3)Balancing Overlay Link Capacities
     One of the most important object of QRON
        Balance the traffic among the overlay links

        Less affected by the dynamics of the
         nonoverlay traffic
        Similar residual capacities at all links

        Residual link capacity deviation(RLCD) is
         defined as




                                                       37
     Performance Evaluation
simulation results and discussions




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     Performance Evaluation
simulation results and discussions




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       Performance Evaluation
  simulation results and discussions

4)Balancing Overlay Broker Overheads
     Another function of QRON
        Balance the overlay routing overhead among
         all the OBs
        Balance the OBs’ residual computation
         capacities
        OB Residual Capacity Deviation is defined as




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     Performance Evaluation
simulation results and discussions




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     Performance Evaluation
simulation results and discussions




                                     42
                     Related Work
   Application-specific overlay network
          Overcast
               Provide bandwidth sensitive multicast
          RMX
               Scalable multicast to real-time heterogeneous
                receivers
          Routing in overlay multicast network
               Balance the multicast traffic among multicast
                service nodes and maintain low end-to end
                latency
               Not balance the traffic among the peer link
          Resilient overlay network (RON)


                                                                43
                     Related Work
   General overlay service network
          Yoid
               Support streaming broadcasts,bulk email
                distribution
          Planet-Lab
               A testbed and a deployment platform
          Opus
               Like Planet-Lab , a test bed
          X-bone
               IP layer and IP tunnel technique
          OverQoS
               Provide QoS with controlledloss rate
          SON


                                                          44
                     Conclusion
   The goal of QRON
       Using the MSDP or the PBSP algorithm to
        balance the overlay traffic
       The hierarchical architecture
          provide scalable in distributing network state
           information
          Up-to-date information

       Adaptive routing during data transfer
          A partial backup path to bypass the traffic

   Simulation show that QRON can
    effectively meet the goal


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