1. Accelerating Peer-to-Peer Networks for Video Streaming
Group 2
Andrew Doherty
Aaron Wroblewski
Raghav Chawla

2. Introduction
Radial Reception Control Protocol (R2CP) enables real-time streaming of multimedia files over P2P networks
R2CP uses RCP, which is similar to TCP but streamlined for P2P real-time usage
New method of scheduling using rankings

3. Background and Motivation
Peer-to-peer (P2P) overlay networks growing in popularity
Widely used for file transfers, but not real-time streaming
Most popular types of shared files are multimedia (music and video)

4. Streaming Model (Peer to Peer)
352x240 VCD
1.38
Mbps
The Problem Statement
Traditional Download Model
Server
Home PC
83 Minutes
To Start Watching!!
1.5 Mbps
≥ 1.5 Mbps
Streaming Model (Peer to Peer)
256 Kbps
1.5 Mbps
Need 6 times available Bandwidth!

5. Challenges Bandwidth Requirements Ensuring In-Order Packet Arrival
Peer Diversity
Bottleneck Bandwidth
Latency
Peer Transience
Users have short sessions in P2P
Random Disconnects
Bottleneck Bandwidth:
Downstream: 1-10 Mbps
Upstream: 100 Kbps – 5 Mbps
Latency:
less than 70ms – More than 280 Ms
Transience:
Short Sessions: Median Session is 60 mins.
60% active for no more than 10 mins.

6. R2CP Architecture RCP R2CP Engine Individual Paths TCP Clone
Receiver Driven
R2CP Engine
Aggregate Connection
Coordinates RCP
Packet Scheduling

7. Dynamic Binding Sequence Numbers Loss Recovery Pipe Management
Local -> Global
Loss Recovery
Coordinate losses with deadlines
Pipe Management
Reassign data from closed pipes to other pipes

8. Packet Scheduling Goals Methodology Ensure In-Sequence Delivery
Minimize Packet Loss due to
Buffer Overflows
Missing Deadlines
Methodology
Congestion Control
Rank Data Structure

9. Packet Scheduling Congestion Control Ranking Data-Structure
RCP Notifies R2CP Engine when is has available slots in congestion window
R2CP sends a data echo request to the source
Ranking Data-Structure
R2CP ranks each request by an approximated arrival time
Request order is determined by rank and last packet requested

10. Protocol Operations R2CP Manages RCP Pipes Handle RCP Sender RCP pipes
Sequence numbers
Transmission/Receipt
RCP Pipes Handle
Congestion Windows
Loss Notification
RCP Sender
Echos Data

11. Performance Evaluation Model
Varied Network Conditions
Compared performance of R2CP to:
Ideal Conditions
Multiple Sockets
R2CP without RTT-scheduling

12. Results - Scalability Rate Differential Delay Differential Traffic
Fluctuations

13. Results – Multipoint-to-Point Video Streaming
Instantaneous Data Rate
Playout Buffer Occupancy
Resequencing
Buffer
Occupancy

14. Related Work
“On multiple description streaming with content delivery networks,” in Proceedings of IEEE INFOCOM, June 2002
Proposes approach that uses multiple description coding for video streaming over multiple servers
However P2P network users are not static so this doesn’t apply
“Distributed video streaming over Internet,” in Proceedings of SPIE Multimedia Computing and Networking, Jan. 2002
Stream video from multiple distributed video servers
Requires synchronization between servers
“PROMISE: Peer-to-peer media streaming using CollectCast,” in Proceedings of ACM Multimedia, Nov. 2003
P2P streaming using multiple sources using UDP connection for streaming with TCP connection for sending control info
Requires lower layer service and use of separate TCP connections for updates adds additional overhead

15. Critique
Specific operation of the ranking/scheduling algorithm difficult to understand
Examples would have been helpful
Larger scope simulation with more sources with less ideal conditions

16. Summary and Conclusions
R2CP is a viable method to enable real-time multimedia streaming over P2P networks
R2CP is receiver-driven, requiring little overhead from multiple sources
R2CP implements effective reliability and congestion control