Optical Multicasting for Interactive Realtime Application in Sparse Splitting Optical Networks

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Optical Multicasting for Interactive Real-time
Application in Sparse Splitting Optical Networks
APAN Network Research Workshop 2007

• Ju-Won Park, Hyunyong Lee, and JongWon Kim
• 2007/ 08/ 27

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Contents

• Introduction
• Related Work
• Constrained Optical Multicast Routing
• Problem statement
• The proposed light-tree construction algorithm
• Experiment Results
• Conclusion

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Introduction
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Multicast over WDM networks

• Multicast in IP over WDM Networks
• IP layer multicast
• Multicast via WDM unicast
• WDM layer multicast
• Multicast tree constructed by the IP layer can
  make copies of a data packet and transmit a copy
  to each of its child
• Require O/E/O conversion
• Undesirable
• Inefficient
• Long latency

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Multicast over WDM networks

• Construct a virtual topology consisting of a set
  of lightpaths from the multicast source to each
  destination (b)
• Using multiple unicasts
• Inefficient bandwidth large multicast session
• WDM switches make copies of data packets in the
  optical domain via light splitting (c)
• More desirable transmission to different
  destinations can now share bandwidth on common
  link
• Useful to support high-bandwidth multicast
  application such as HDTV.
• WDM layer multicast potential advantages
• Knowledge of the physical topology more
  efficient multicast routing is possible
• Light splitting is more efficient than copying
  packets
• Avoid the electronic processing bottleneck
• Support of coding format and bit-rate
  transparency across both unicast and multicast

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Related Work
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Related Work

• The main mechanism of transport over optical
  network is light-path, a point to point all
  optical channel connecting from source to
  destination.
• To incorporate optical multicasting capability, a
  light-tree, light-forest concept is introduced.
• The problem of constructing a light-tree that
  spans a given source and a set of destinations is
  similar to the Steiner tree problem which is
  known to be NP-complete
• Consider several new issues and complexities for
  QoS provisioning of optical multicasting
• Sparse splitting (X. Zhang, J. Wei and C. Qiao,
  Constrained Multicast Routing in WDM Networks
  with Sparse Light Splitting, in J. of Lightwave
  Technology, vol. 18, no. 12, December 2002.)
• Power constraint (Y. Xin and G. Rouskas,
  Multicast routing under optical layer
  constraints, In Proc. of INFOCOM 2004)
• Delay boundary (M. Chen, S.Tseng, B. Lin,
  Dynamic multicast routing under delay
  constraints in WDM networks with heterogeneous
  light splitting capabilities, in Computer
  Communications 29 (2006) 1492-1503)

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Constrained Optical Multicast Routing

• Problem statement
• The proposed light-tree construction algorithm

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Problem Statement

• Sparse splitting optical network
• MC (multicast capability) node
• MI (multicast in-capability) node
• We define a delay function which assigns a
  nonnegative weight to each link the network
• To deliver interactive real-time application via
  light-tree, we consider three parameters
• Adequate signal quality power constraint
• End-to-end delay boundary
• inter-destination delay variation boundary

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Constrained Optical Multicast Routing

• Goal
• Every member of session is connected
• Satisfy the delay and inter-destination delay
  variation tolerance
• Balanced tree to guarantee a certain level of
  optical signal power
• The way
• Adopt hierarchical approach

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Constrained Optical Multicast Routing

• Make multicast backbone network
• Build the auxiliary MC network as referred as
  multicast backbone network,
• Every MC node is included.
• Adjacent MC node is connected using logical link
  if there is available wavelength on the path. If
  there are multiple path between MC nodes, the
  shortest path is selected.
• The delay of logical link is equal to the delay
  summation of path

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Constrained Optical Multicast Routing
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Constrained Optical Multicast Routing

• Build the light-tree based on application
  requirement
• Source searches the MC node which is nearest from
  source as referred to primary MC node.
• The primary MC node is unique of each session
• Build the light-tree which has primary MC node as
  root in multicast backbone network based on
  constraints.

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Constrained Optical Multicast Routing
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Constrained Optical Multicast Routing

• Each destination selects a adequate MC node
• The MC selection by receiver is a key to
  construct feasible light-tree
• Each MI node finds the subset of on-tree MC nodes
  which satisfy the delay boundary
• MI node chooses the MC node which has minimum
  fanout in subset and then, join the light-tree by
  connection with selected MC node

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Constrained Optical Multicast Routing
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Constrained Optical Multicast Routing

• Completed light-tree meets the delay boundary
  with balanced aspect.
• It does not satisfy the inter-destination delay
  variation boundary.
• Reduce the inter-destination delay variation by
  swapping MI nodes

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Constrained Optical Multicast Routing
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Constrained Optical Multicast Routing

• Advantages
• Source need not know about the location of
  destinations.
• Every destination need not find the minimum cost
  path from itself to source. It just must find
  the location of MC node which satisfies
  application requirement.
• Simple construction of member-only light-tree
• The procedure of joining the light-tree is only
  performed at member.
• The procedure of dynamic addition or deletion of
  members in a group is simple.
• Join The node which wants to join in the
  multicast session can be connected to its nearest
  MC node.
• Leave The node which wants to leave can be
  disconnected send the prune message to connected
  MC node.

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Experiment Results
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Experiment Results
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Experiment Results
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Conclusion
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Conclusion Future Work

• To support multicast in optical network
• a balanced light-tree to guarantee signal quality
• Delay and inter-destination delay variation along
  all source-destination paths in the tree should
  be bounded in sparse splitting optical network.
• The proposed algorithm is heuristic approach to
  obtain the feasible light-tree
• Wavelength assignment algorithm should be
  explored in future research.
• Minimize wavelength cost

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QA