Protocol Design for Scalable and Adaptive Multicast for Group Communication

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Protocol Design for Scalable and Adaptive
Multicast for Group Communication

• De-Nian Yang and Wanjiun Liao
• ICNP'08
• Presented by Lei Sun

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Background Motivation 1/3

• Multicast communications
• IP Multicast
• Each router need to store a forwarding state for
  each multicast group.
• Explicit Multi-Unicast (Xcast)
• Addresses of the multicast tree are included in
  the header of multicast packet data.

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Background Motivation 2/3

• Adaptations
• IP multicast
• Not scalable in term of the number of group
  considering routers memory.
• Xcast
• Not scalable in term of the group size
  considering the delay.
• Problems
• Network may suffer scalability problems if end
  users choose the improper Multicast
  communication method.

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Background Motivation 3/3

• Scalable and adaptive protocol
• Scalable both in terms of group size and group
  number
• Optimal solution
• Routers with forwarding states can be either
  branching or non-branching
• Adaptive to the dynamic group members
• Extendable in existing tree

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Design

• REMOVE MOVE
• Minimize the number of router which store the
  forwarding states.
• States Messages
• Support dynamic group membership and rerouting of
  multicast trees when the network topology is
  changed.

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Protocol operations (1/4)

• States
• Group ID (IP addresses)
• Maximum number of addresses in each Xcast packets
• Join timers
• Move_Up timer
• Addresses of parent node and upstream state node
• Addresses of downstream state nodes
• Move_Down timer
• messages
• Join
• Leave
• Inform_Up_note
• Move_Up
• Move_down

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Protocol operations (2/4)
(a) Node 8 joins the multicast tree.
(b) Node 2 finds that the forwarding state of
node 4 can be removed.
(c) The forwarding state of node 4 is removed.
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Protocol operations (3/4)
(d) Node 7 creates a forwarding state at node 4.
(e) The forwarding entry of node 7 is moved to
node 4.
(f) After the network topology changes, node 1
is the new upstream state node of node 11.
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Protocol operations (4/4)
(g) Since node 1 has three downstream state nodes
from the interface to node 3, it creates the
forwarding state at node 3.
(h) The forwarding state of node 1 from the
interface to node 3 is moved to node 3.
(i) After the forwarding state of node 4 is
removed, the assignment of the state nodes is
optimal.
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Simulation Results (1/2)
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Simulation Results (2/2)
Fig. 3. Average number of state nodes in a
multicast tree in different graphs with different
d and different group sizes.
Fig. 4. Protocol overheads in different networks
with different d and different group sizes.
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Conclusion

• Unprofessional writing
• Bad organized