P2P Content Distribution BitTorrent and Spotify Amir H. Payberah amir@sics.se Amirkabir University of Technology (Tehran Polytechnic) Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 1 / 62
Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 2 / 62
Possible Solutions for Content Distribution Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 3 / 62
Client-Server Model Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 4 / 62
Client-Server Model Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 5 / 62
Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 6 / 62
The Client-Server Model Problems ◮ Scalability? Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 7 / 62
The Client-Server Model Problems ◮ Scalability? ◮ Single Point of failure? Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 7 / 62
The Client-Server Model Problems ◮ Scalability? ◮ Single Point of failure? Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 7 / 62
Client-Server Systems Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 8 / 62
The Client-Server Model Problem Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 9 / 62
Scalable and Fault-Tolerant Client-Server Model Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 10 / 62
Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 11 / 62
Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 12 / 62
Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 13 / 62
Peer-to-Peer Model Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 14 / 62
Peer-to-Peer (P2P) Model Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 15 / 62
P2P Challenges ◮ Churn in the system ◮ Free-riding problem ◮ Bottleneck in the overlay network ◮ Connectivity problem, e.g., NAT Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 16 / 62
Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 17 / 62
Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 18 / 62
How To Discover Data? Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 19 / 62
Possible Solutions - First Generation ◮ Central directory Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 20 / 62
Possible Solutions - Second Generation ◮ Flooding Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 21 / 62
Possible Solutions - Third Generation ◮ Distributed Hash Table (DHT) Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 22 / 62
P2P Content Distribution Applications - File Sharing Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 23 / 62
P2P Content Distribution Applications - Media Streaming Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 24 / 62
Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 25 / 62
BitTorrent ◮ BitTorrent is a system for efficient and scalable replication of large amounts of static data. Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 26 / 62
BitTorrent Players Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 27 / 62
Files ◮ Files are broken into pieces of size between 64KB and 1MB. Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 28 / 62
.torrent Files ◮ Metadata ◮ Contains: • URL of tracker • Information about the file, e.g., filename, length, ... Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 29 / 62
The Core Idea ◮ A peer obtains .torrent file. Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 30 / 62
The Core Idea ◮ A peer obtains .torrent file. ◮ It, then, connects to the tracker. Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 30 / 62
The Core Idea ◮ A peer obtains .torrent file. ◮ It, then, connects to the tracker. ◮ The tracker tells the peers from which other peers to download the pieces of the file. Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 30 / 62
The Core Idea ◮ A peer obtains .torrent file. ◮ It, then, connects to the tracker. ◮ The tracker tells the peers from which other peers to download the pieces of the file. ◮ Peers use this information to communicate with each other. Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 30 / 62
The Core Idea ◮ A peer obtains .torrent file. ◮ It, then, connects to the tracker. ◮ The tracker tells the peers from which other peers to download the pieces of the file. ◮ Peers use this information to communicate with each other. ◮ The peers send information about the file and themselves to tracker. Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 30 / 62
Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 31 / 62
Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 32 / 62
Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 33 / 62
Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 34 / 62
Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 35 / 62
Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 36 / 62
Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 37 / 62
Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 38 / 62
Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 39 / 62
Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 40 / 62
What About Free Riders? Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 41 / 62
Tit-For-Tat Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 42 / 62
Question ◮ From which peers download the pieces? Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 43 / 62
Peer Selection ◮ Use choking algorithm to choose peer to download pieces. ◮ Decision to choke/unchoke based on tit-for-tat. Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 44 / 62
Discover More Cooperating Peers ◮ Optimistic unchoking ◮ Allocate an upload slot to a randomly chosen uncooperative peer Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 45 / 62
Snubbed Peers ◮ If all its peers choke it. ◮ Increase the number of optimistic unchokes. Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 46 / 62
Question ◮ Which piece? Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 47 / 62
Piece Selection ◮ Rarest first: common parts left for later Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 48 / 62
Piece Selection ◮ Rarest first: common parts left for later ◮ Random first piece: start-up need to get a complete piece Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 48 / 62
Piece Selection ◮ Rarest first: common parts left for later ◮ Random first piece: start-up need to get a complete piece ◮ Endgame mode: broadcast for all remaining blocks Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 48 / 62
BitTorrent Extension ◮ Distributed tracker ◮ Peer-exchange Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 49 / 62
Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 50 / 62
Spotify ◮ Active users: over 50 million ◮ Number of songs: over 20 million ◮ Number of songs added per day: over 20000 ◮ Number of playlists: over 1.5 billion created so far ◮ Available in 58 countries ◮ Legal Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 51 / 62
The Core Idea ◮ Request first piece from Spotify servers. Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 52 / 62
The Core Idea ◮ Request first piece from Spotify servers. ◮ Meanwhile, search P2P network for remainder. Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 52 / 62
The Core Idea ◮ Request first piece from Spotify servers. ◮ Meanwhile, search P2P network for remainder. ◮ Switch back and forth between Spotify servers and peers as needed. Amir H. Payberah (Tehran Polytechnic) P2P Content Distribution 1393/8/27 52 / 62
Recommend
More recommend