Seminar Presentation

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Seminar Presentation

• Layered Reliable Multicast
• Kadar Shahar Gorkov Eugene
• Supervisor Gidon Gershinsky

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Project Goals

• Design and implement a massively scalable
  multicast protocol.
• Provide multi-rate content delivery to large sets
  of receivers.
• Implement congestion control mechanism for
  layered one-way transmission.

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Project Block Diagram
Sender Application
Multiple Receivers
Our Project
LCT LCC
Multicast IP
Session Log
UDP
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Project Status

• High level design including class diagram of the
  project is completed.
• A very simple sender and receiver applications
  with very limited functionality were already
  implemented (skeleton).

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Expected Problems

• Emulate network with variable packet loss rate
  per receiver.
• Implementing the protocol in most generic way to
  be undependable on the application.

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Schedule

• Week by week roadmap

Protocol Implementation
Top Level Application Finalization
Testing Debug
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Theoretical Background

• The protocol is named Layered Coding Transport
  (LCT).

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Theoretical Background (Cont.)

• Receiver driven Layered Congestion Control (LCC).
• Receivers adjust their reception rate by joining
  and leaving groups (layers) with no feedback to
  the sender.
• Rate adjustment similar to TCP.
• Receiver transparency (receiver sees dedicated
  unicast session).
• Sender transparency (outgoing rate independent of
  receivers number).

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Theoretical Background (Cont.)

• LCC has two approaches Static and Dynamic.
• Static is simpler.
• Dynamic is designed to overcome IGMP leave
  latencies.
• Reliability is ensured by Forward Error
  Correction algorithm (wont be implemented).

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Theoretical Background (Cont.)

• Static Layer Scheme
• Each group(layer) has a constant rate
• Each receiver can be in one group at a time
• Receiver moves from group to group according to
  packet loss rate
• Used when IGMP leave latency is relatively short

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Theoretical Background (Cont.)

• Dynamic Layer Scheme
• Each layer has a dynamically changing rate
• Each receiver may be in multiple groups at a time
• Receiver joins groups according to packet loss
• Used when IGMP leave latency is long (few
  seconds)

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Dynamic Scheme
Receiver