MZR: A Multicast Protocol based on Zone Routing

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MZR A Multicast Protocol based on Zone
Routing

• Vijay Devarapalli
• Nokia Research Center
• Dr. Deepinder Sidhu
• Maryland Center for Telecommunications Research

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Presentation Overview

• Introduction to MZR
• Proactive and Reactive Routing Protocols
• Zone Routing Protocol
• Details of how MZR functions
• Performance Analysis
• Conclusions

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Introduction to MZR

• What is MZR?
• Its a source initiated on-demand multicast
  routing protocol
• Builds a multicast delivery tree rooted at the
  source based on the zone routing protocol
• Does not depend on any underlying unicast
  protocol for global routing substructure
• Why Multicast?
• Ad hoc network ? collaborative computing

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Proactive versus Reactive

• Proactive Routing Protocols
• Exchange routing information periodically to
  maintain an up-to-date routing table
• React to each network topology change
• Problems
• High percentage of bandwidth used for routing
  information
• Only a small fraction of the control traffic may
  be used

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Proactive versus Reactive

• Reactive Routing Protocols
• An initial route discovery process
• Minimal reaction to topology change
• Problems
• Route information may not be available at the
  time of route request
• The route discovery process is typically
  implemented as a global flood-search procedure
• Explosion of control traffic

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Zone Routing Protocol

• Hybrid (proactive and reactive) routing protocol
• Proactive procedure limited to nodes local
  neighborhood (zone)
• Global search is carried out by querying selected
  (border) nodes

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Details of MZR

• Zone Construction and Maintenance
• Each node constructs a zone around itself using a
  pre-configured radius
• Zone Routing Table built using ADVERTISEMENT
  packet
• Periodic advertisements keep routing table
  up-to-date
• Interior and Border nodes can be identified using
  the Zone Routing Table

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Details of MZR

• Multicast Tree Creation
• For each multicast session a tree rooted at the
  source is created.
• The tree is identified by ltsource, groupgt pair
• Multicast route entry consists of
• Multicast session id
• ltsource, groupgt pair
• IP address of upstream node
• A list of the downstream nodes

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Details of MZR

• Multicast Tree Creation (continued)
• Tree Creation is a two step process
• Step 1 Extend tree inside zone
• Source sends a TREE-CREATE to each zone node
• As the TREE-CREATE packet is propagated reverse
  routes are created at each intermediate node
• An interested node replies with a TREE-CREATE-ACK
• The TREE-CREATE-ACK is sent back through the
  reverse route
• As it propagates, the multicast route entry is
  completed and activated

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Details of MZR

• Multicast Tree Creation (continued)

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Details of MZR

• Step 2 Extend tree to the entire network
• Source sends a TREE-PROPAGATE message to border
  nodes
• On receiving the TREE-PROPAGATE the border node
  does the following things
• Sends a TREE-CREATE packet to all its zone nodes
  and the procedure described in Step 1 is followed
• Once it is done with the zone nodes it sends a
  TREE-PROPAGATE message to its border nodes

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Details of MZR
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Details of MZR

• Routing Mechanism
• Source starts transmitting once the multicast
  delivery tree is created
• Internal nodes of the tree replicate received
  data packets and send a copy to each node on the
  downstream list
• Transmission to a downstream node is stopped once
  that node migrates

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Details of MZR

• Maintaining up-to-date routing information
• Timer for each route entry
• Stale route entries removed on time-out
• To keep routes active within multicast session
  source sends TREE-REFRESH packet

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Details of MZR

• Reaction to Link Breaks
• Downstream nodes responsible for detecting link
  breaks
• On detecting a link break the downstream node
  initiates a global search using the zone routing
  mechanism
• Similar method to Tree creation
• JOIN JOIN-ACK
• JOIN-PROPAGATE

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Details of MZR

• Leaving a multicast group
• When tree member wants to leave the group it
  sends an TREE-PRUNE message to its upstream node
• The upstream node removes the node from its
  downstream list
• If the downstream list of an intermediate node
  becomes empty then it sends a TREE-PRUNE to its
  upstream node

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Performance Analysis

• Simulation Model
• 50 mobile nodes moving according to the random
  waypoint model on a 500m x 500m 2D grid
• Running time of simulation was 300 seconds
• Transmission range is set to 100 meters
• Link capacity assumed to be 2 Mbps

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Performance Analysis

• Packet Delivery Ratio (PDR) and Node Mobility
• PDR D / N
• D ? number of data packets actually delivered to
  multicast group members
• N ? total number of packets that were supposed to
  be delivered

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Performance Analysis

• Packet Delivery Ratio (PDR) and Node Mobility

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Performance Analysis

• Routing Overhead and Node Mobility
• Ratio of control packets sent versus all packets
  sent

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Performance Analysis

• Routing Overhead and Multicast Group Size

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Performance Analysis

• Packet Delivery Ratio and Multicast Group Size

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Conclusions

• New source initiated, on demand multicast routing
  protocol for ad hoc networks
• Builds a multicast delivery tree and does not
  depend on any underlying unicast mechanism
• Every multicast receiver in the ad hoc network
  joins in finite time
• Scales well for different group sizes and
  different mobility speeds