Traffic Localization with Information Guidance of Pseudo Peer Agent on BT-P2P Network 學生 : 楊宏昌 指導教授 : 曾黎明教授 在 BT 同儕通訊上利用參與者訊息引導對外流量之區域化節約

Outline Introduction Relate Work System Design Experiment Conclusions

Introduction P2P system Each client is a server Improves system scalability Robustness Peers are transient, not stable cache BitTorrent (BT) resource utilization than any currently known cooperative technique.

Introduction (cont.) Problem Have redundant traffic flow from WAN Why Peers cannot identify foreign peers or local peers Base on “ tit-for-tat ” policy,peers will select the peers with highest upload speed to exchange data Foreign peers and local peers have similar upload speed LAN Internet

Introduction (cont.)

Related Work Cache Cache data in the gateway of the LAN When internal peer request pieces from external, cache will intervenes and give local copy to client Need additional disk space to cache pieces

Related Work (cont.) Gateway peer The only node inside the LAN that can connect to external peers Need a super peer that have high upload bandwidth and additional disk space

Goal Goal: Reduce redundant traffic flow from WAN Local users share resource to each other Concept Do not modify client Not supply a stable cache

Web server End users Router Trackers peers download the metainfo file(.torrent) 2 Ask for file owners 3 Get subset of the participators 4 Request for file downloading 5 Send back requested Item 6 Browse the Website 1 Bittorrent

BT (tit-for-tat) choke / unchoke Decide which peer to upload Every 10 seconds, four with the highest download rate to this peer are unchoked Every 30 seconds, peer chooses a neighbor at random to unchoke Other peer are choked

BT (piece selection) When client can request some pieces from his neighbors Default behavior is “ rarest first replication ” algorithm Request the piece that is rarest among his neighbors This is local rarest, not global rarest

BT (summary) Why end user not get pieces from other LAN users in bittorrent The peer list from tracker is random According to tit-for-tat algorithm LAN users will not give pieces to end user

Method Job dispatching Different client will request different pieces first Tracker and pseudo peer agent work together to guide clients which pieces to request Local share first Peers in LAN share resource to each other

System Architecture

System Component Torrent Agent Intercepts metainfo file Modifies metainfo file Caches metainfo file Tracker agent Get external peer list Distribute predefined peer list to end user

System Component (cont.) Peer Agent Give pseudo piece information to end users Handle the request from end users

System Scenario Diagram Metainfo Get Tracker query

System Scenario Diagram Piece that have Piece not have Piece request

System Scenario Diagram Piece that have Piece not have Piece transfer

System Scenario Diagram Piece that have Piece not have Piece transfer

Experiment Peer Agent : Bittorrent Python 2.4 Seed and Peer Bitcomet 0.67

Experiment 1 File : Kbytes Piece that have Piece not have

Experiment 1

Experiment 2 D know A and C E know A and B File : Kbytes

Experiment 2 縱軸 : 重複頻寬的比例 橫軸 :Peer agents 的個數

Experiment 3 1 seed and 6 peers Every user have 3 peer agents File : Kbytes

Experiment 3 縱軸 : 重複頻寬的比例 橫軸 :End user 的個數

Experiment 3

Conclusion We propose a method use information guidance by pseudo peer agent to reduce redundant traffic flow from WAN Experimental results show that our system will reduce the ratio of redundant traffic above 25% for every user and reduce complete time 20%