QoS-Based Multicast Routing for Distributing Layered Video to Heterogeneous Receivers in Rate-based Networks

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QoS-Based Multicast Routing for Distributing
Layered Video to Heterogeneous Receivers in
Rate-based Networks

• Bin Wang and Jennifer C.Hou

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• Goal
• QoS requirements of heterogeneous receivers,
  including bandwidth and delay
• Highest receiving quality for receivers
• Minimize the total network resource consumption
• Solution
• SourceLayered encoding(cummulative)
• Receivers tradeoff between video quality and
  available bandwidth
• Scheduling rate-based link scheduling
• Tree construction on weighted digraph G(V,E)
  using the global state and an auxiliary routing
  table

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Global state

• Link state
• Available bandwidth b(l), bE?R,the link
  bandwidth function,
• Constant delay dl,which depends on the
  capacity,the propagation delay, and the maximum
  packet size
• Link cost
• Node state available buffer
• Global state
• The collection of the local node/link state of
  all the nodes in the network
• Maintained by every node in the network

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The Auxiliary Routing Table

• T is a V X H matrix, recording a h-hop maximum
  bandwidth path
• P path
• bwmaximum bandwidth on P
• Neighbournext hop
• dhsum(dl) end-end constant delay
• every node maintains a T

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Rate-based Scheduling Algorithms

• Algorithms Generalized Processor
  Sharing,Weighted Fair Queuing,Virtual Clock
• Traffic model leaky bucket (R,sigma)
• End-end delay bound on P
• D(r,P)(sigmaPc)/rsum(dl)

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Traffic Model for Layered Video

• Each layer leaky bucket(R,Sigma)
• Video signal (Ri,sigmai), i1m (of layers)
• Layer k (Rk,sigmak),
• Rksumj1k(Rj)
• sigmaksumj1k(sigmaj)
• Layers are selectively forwarded on links

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Problem Formulation

• The one-to-many multicast video distribution
  session
• ssource
• djj1n receivers
• Djj1ndelay requirements
• Rjrj1nmaximum acceptable rates, layer-k
  receiver j RkltRjrltRk1
• How to construct a tree?

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Algorithm Overview

• Starting from a tree with only s
• Higher-layer receiver i first
• Select the most appropriate path P from T
• A setup message is sent to i along P, carrying
  the data structure RECEIVER and D(delay)
• RECEIVER is updated by intermediate nodes, if
  better path is available
• Next off-tree receiver j is selected by i
• A fork message is sent from i
• A finish message is sent to s if no off-tree node
  

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The RECEVIER data structure

• RECEIVER.RECEIVERi records the least-hop
  appropriate path P for receiver i
• OnTreeNode initialized to s
• path P, with sufficient bandwidth
• r the minimum bandwidth ri for delay
• cost Pr, the total bandwidth due to receiver
  i(only for new branch)
• Rr maximum acceptable rate Rri
• level of layers
• tag on-tree or off-tree

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Path Selection from T

• Calculate the minimum bandwidth ri according to
  deley requirement
• rigt(sigmakpc)/(Di-sum(dl))
• Select the least-hop path with T(i,h).bwgtmax(ri,R
  k)
• No loop
• Reserved bandwidth max(ri,Rk)
• if no path exists,or rigtRri, degrading layer
• (Lower cost? Best path?)

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Next Off-Tree Receiver Selection

• Higher layer Smaller cost node first
• Gk1Gm0, Gkltgt0
• Select the receiver i from Gk with min(Pri)
• RECEIVERi.tagtrue
• A setup message is sent to i
• i will select next receiver j
• i sends a fork message to RECEIVERj.OnTreeNode

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Path Update

• Intermediate nodes update DRECEIVER
• Delay requirement (Dcumulative delay)
  DigtD(sigmakpc)/risum(dl)
• Select the minimum-hop path P from T(first entry
  T(i,h))
• Smaller cost(total bandwidth) Pri
• Update RECEIVER for every receiver i if smaller
  cost

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Dynamic Receiver Join/Leave

• Goal seamless transition via incremental
  changing
• Leave
• Leaf node leave message is sent upstream,and
  resource is released by a fork node
• Non-leaf node just relay incoming downstream
  messages

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Dynamic Receiver Join/Leave(cond.)

• Join
• Join request to s with diRir
• S multicasts a join message with RECEIVERiD
  to all(?) on-tree receivers
• Intermediate nodes updates D,and RECEIVER if
  smaller cost path available
• The leaf receivers send back RECEIVER
• S select a fork node with least cost
• fork message
• (Why not use updated T? Least cost?)

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Auxiliary Routing Table T Update

• Compute the h-hop maximum bandwidth paths from
  the current node to all the other nodesiterate H
  times, h1H
• Update T(j,h)(j1V) for every neighbour u of
  j, if no loop
• T(j,h).bwmax(T(j,h).bw,min(T(u,h-1).bw,b(u,j))
  )
• If loop exists(j in T(u,h-1).P), recursively
  calculate a new T(u,h-1) excluding j
• For complexity, excluding u if loop or limit the
  scope of recursion
• Run off-line and infrequently

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Complexity

• of messages O(2d)
• T update exponential in the worst case
• If bapassing the loop
• Check every neighbour u of j O(V)
• Check loop and bw O(H)1
• Run H times for every receiver
• O(H)O(V)
• So O(H2V2)

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Simulation

• Topology
• vBNS , switch cluster,random network(Waxman
  method, which can obtain real world networks)
• Simulator NetSimQ
• Comparing
• maximum bandwidth tree algorithm
• Maxemchuks algorithm
• Varing parameters lambda(session arrival
  rate),d,Dj
• Performance metrics total bandwidth required,
  percentage of receivers attaining QoS

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Maxemchuks Algorithm

• Minimize bandwidth consumption without
  considering QoS requirement
• Use modified T-M heuristic
• A variant of steiner tree problem construct a
  minimum cost tree for a subset of nodes,
• with link cost fixed in the network
• Link cost basic cost highest reserved rate
• Construct from higher-rate receivers and then add
  lower-rate of receivers
• No explicit QoS consideration
• Centralization

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Max Bandwidth Tree Algorithm

• For Layered-encoded data (cumulative)
• Compute the maximum available bandwidth tree to
  connect all receivers,receivers are classified by
  receiving capabilities
• Minimize the sum of satisfaction level
• For shorter pathselect the node nearest to
  source (not guarantee shortest path)
• For bandwidth saving reduce bandwidth from the
  receivers

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Simulation results
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Simulation results(cond)
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Simulation results(cond)
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Simulation results(cond)
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Issues

• The original Goal is achieved
• Shortest path? Smallest total cost?The best path?
• Complexity (scalability?)
• Global state
• T update
• Link state update
• Complexity!
• A good attemption!

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A Better Solution?