QRON: QoSAware Routing in Overlay Networks

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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

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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 networkOverlay 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 networkOverlay Broker (OB)
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Overlay service networkOverlay Broker (OB)
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Overlay service networkFunctional 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

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Overlay service networkFunctional Modules of OSN
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Overlay service networkFunctional 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 networkFunctional 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

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Overlay service networkFunctional 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

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QRONProblem 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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QRONBasic 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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QRONPath 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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QRONPath 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

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QRONPath 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 gt link(m,n)'s Bmn
• The probability of choosing link(i,j) Pij gt Pmn
• If (Bij-RB)/Bij gt (Bmn-RB)/Bmn
• Then BijgtBmn and PijgtPmn
• Define Pij as (Bij-RB)/Bij
• The weight of the link is defined as
• ((Bij)/(Bij-RB))

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QRONPath 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

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QRONHierarchical 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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QRONHierarchical Organization
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QRONHierarchical Organization
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QRONHierarchical Organization
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QRONHierarchical Organization
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QRONHierarchical Organization
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(No Transcript)
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QRONHierarchical Organization
Composed of virtual overlay links
Composed of virtual overlay links
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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 Evaluationsimulation 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)

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Performance Evaluationsimulation 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.

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Performance Evaluationsimulation 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

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Performance Evaluationsimulation results and
discussions
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Performance Evaluationsimulation results and
discussions
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Performance Evaluationsimulation 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 Evaluationsimulation results and
discussions
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Performance Evaluationsimulation results and
discussions
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Performance Evaluationsimulation 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

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Performance Evaluationsimulation results and
discussions
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Performance Evaluationsimulation results and
discussions
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Performance Evaluationsimulation 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 Evaluationsimulation results and
discussions
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Performance Evaluationsimulation results and
discussions
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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)

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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

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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