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Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar
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Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

Dec 23, 2015

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Page 1: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

Receiver-driven Layered Multicast

Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996

Presented By – Manoj Sivakumar

Page 2: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

Overview

Introduction Approaches to Rate-Adaptive

Multimedia Issues and challenges RLM - Details Performance Evaluation Conclusions

Page 3: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

Introduction

Consider a typical streaming Application

What rate should the source send data at ?

Internet ReceiverSource128 Kb/s X Kb/s

Page 4: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

Approaches to Rate-Adaptive Multimedia

Rate Adaptation at Source – based on available network capacity Works well for a Unicast environment How about multicast ?

source Receiver 2128 Kb/s X2 Kb/s

Receiver 1

Receiver 3

X1 Kb/s

X3 Kb/s

Page 5: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

Example of Heterogeneity

Page 6: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

Issues and Challenges

Optimal link utilization Best possible service to all receivers Ability to cope with Congestion in the

network All this should be done with just best

effort service on the internet

Page 7: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

Layered Approach

Rather than sending a single encoded video signal the source sends several layers of encoded signal – each layer incrementally refining the quality of the signal

Intermediate Routers drop higher layers when congestion occurs

Page 8: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

Layered Approach

Each layer is sent to one multicast group

If a receiver wants higher quality – subscribes to all higher level layer multicast groups

Page 9: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

Issue in Layered Approach

No framework for explicit signaling between the receivers and routers

A mechanism to adapt to both static heterogeneity and dynamic variations in network capacity is not present Solution - RLM

Page 10: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

RLM – Network Model

Works with IP Multicast Assume

Best effort (packets may be out of order, lost or arbitrarily delayed)

Multicast (traffic flows only along links with downstream recipients)

Group oriented communication (senders do not know of receivers and receivers can come and go)

Receivers may specify different senders

Page 11: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

RLM - Video Streams

One channel per layer Layers are additive Adding more channels gives better

quality Adding more channels requires more

bandwidth

Page 12: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

RLM Sessions

Each session composed of layers, with one layer per group

Layers can be separate (i.e. each layer is higher quality) or additive (add all to get maximum quality) Additive is more efficient

Page 13: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

Router Mechanisms

Dropping of packets Drop less preferential packets first

Page 14: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

RLM - Protocol

Abstraction on congestion, drop a layer on spare capacity, add a layer

Page 15: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

RLM – Adding and Dropping layers

Drop layer when packet loss Add does not have counter-part signal Need to try adding at well-chosen

times Called join experiment

Page 16: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

RLM – Adding and Dropping layers

If join experiment fails Drop layer, since causing congestion

If join experiment succeeds One step closer to operating level

But join experiments can cause congestion Only want to try when might succeed

Page 17: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

RLM – Join Experiments

Get lowest layer and start timer for next probe Initially timer small If higher level fails then increase timer

duration else proceed to next layer and start time for the layer above it

Repeat until optimum

Page 18: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

RLM Join Experiment

How to know is join experiment succeeded Detection time

Page 19: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

Detection Time

Hard to estimate Can only be done experimentally Initially start with a large value Progressively update the detection

time based on actual values

Page 20: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

RLM - Issues with Joins

Is this Scalable What if each node does join experiments

and the same time for different layers Wrong info to node that requests lower

layer if the other node had requested higher layer

Solution – Shared Learning

Page 21: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

RLM – Shared Learning

Each node broadcasts its intent to the group Adv’s – other nodes can learn from the

result of this node’s experiment Reduction in simultaneous experiments

Is this still foolproof ??

Page 22: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

RLM - Evaluation

Simulations performed in NS Video modeled as CBR Parameters

Bandwidth: 1.5 Mbps Layers: 6, each 32 x 2m kbps (m = 0 … 5) Queue management :Drop Tail Queue Size (20 packets) Packet size (1 Kbytes) Latency (varies) Topology (next slide)

Page 23: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

RLM - Evaluation

Topologies 1 – explore latency 2 – explore

scalability 3 – heterogeneous

with two sets 4 – large number of

independent sessions

Page 24: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

RLM – Performance Metrics

Worse-case lost rate over varying time intervals Short-term: how bad transient congestion is Long-term: how often congestion occurs

Throughput as percent of available But will always be 100% eventually So, look at time to reach optimal

Note, neither alone is ok Could have low loss, low throughput High loss, high throughput

Need to look at both

Page 25: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

RLM – Performance Results

Latency Results

Page 26: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

RLM – Performance Results

Latency Results

Page 27: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

RLM – Performance Results

Session Size

Page 28: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

RLM – Performance Results

Convergence rate

Page 29: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

RLM – Performance Results

Bandwidth Heterogeneity

Page 30: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

Conclusions

Possible Pitfalls Shared Learning assumes only multicast

traffic Is this valid ?? Is congestion produced by Multicast

traffic alone Simulation does not other traffic

requests!!

Page 31: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

Conclusions

Overall – a nice architecture and mechanism to regulate traffic and have the best utilization

But still needs refinement

Page 32: Receiver-driven Layered Multicast Paper by- Steven McCanne, Van Jacobson and Martin Vetterli – ACM SIGCOMM 1996 Presented By – Manoj Sivakumar.

References

S. McCanne, V. Jacobson, and M. Vetterli, "Receiver-driven layered multicast," in Proc. SIGCOMM'96, ACM, Stanford, CA, Aug. 1996, pp. 117--130.