peer-to-peer(p2p) zhenxiang chen network center of jinan university [email protected]

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Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University [email protected]

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Page 1: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Peer-to-Peer(P2P)

Zhenxiang CHENNetwork Center of Jinan University

[email protected]

Page 2: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Table of Contents

• Background• Definitions• P2P based applications• P2P structure• Challenges• Platform and tools• Conclusion• References and workgroup

Page 3: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Background

Page 4: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

What is peer

Firewall

因特网洲际主干

洲际主干

ISP

消费者用户

第三方内容

Web 服务器

应用服务器

因特网主干

地区网络

企业网提供商

ISP

专业提供商

本地 ISP

T1

社团用户社团网络

数据库

消费者用户

Peer

Peer

Peer

Page 5: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

What is overlay network

• Overlay networks create a structured virtual topology above the basic transport protocol level that facilitates deterministic search and guarantees convergence.

IP

Overlay

IP

Overlay

Page 6: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Application Layer Network

• Application Layer Network• Overlay Network• 网络:定义主机之间通信的寻址

方式、路由方式和服务模型• 在现有的 Internet 传输网络之

上构建一个完全位于应用层的网络系统• 拓扑发现,路由等功能完全由

应用层自己完成,不依赖网络层

• 基于 Internet 网络的大规模的分布式应用

Page 7: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Futures of Application layer Network

• 优点:• 易于部署,不依赖于网络设备的升级• 可扩展性好

• 缺点:• 增加了复杂性和处理开销• 无法利用最佳路由,增加了延迟• 破坏了网络的分层结构模型

• 路由具有“自私”特性 (AS/bandwidth/get and offered)

Page 8: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Other Overlay Networks

• Peer-to-Peer systems• Application layer multicast• VPN• Service Overlay Networks• 6bone• Content distribution networks

6/4

Internet v4

6/4 4

6

6

6

6/4NAT

Page 9: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

12

… …

n-1

A:Sarnoff A:Sarnoff ’’law :law : 规模是规模是 O(n)O(n)

B: Metcalfe B: Metcalfe ’’law :law : 规模是规模是 O(nO(n22))

CCnn33

CCnnn-1n-1

CCnn22

CCnn22

C: Reed C: Reed ’’lawlaw :规模是:规模是 O(2O(2nn))

Sarnoff Sarnoff ’’law(law( 萨萨罗夫定律罗夫定律 )) :效益规:效益规模是模是 O(n)O(n) :网络是:网络是广播媒介,任广播媒介,任 11 发送发送者(设备)和多个者(设备)和多个(n-1)(n-1) 接收者(设接收者(设备)。备)。

Metcalfe Metcalfe ’’lawlaw (( 梅特卡夫定律):效梅特卡夫定律):效益规模是益规模是 O(nO(n22)) 网络网络是全互连媒介,任何是全互连媒介,任何11 个设备可与其它个设备可与其它 n-n-11 个交互,同时存在个交互,同时存在n(n-1)=nn(n-1)=n22-n-n 个并个并发执行的事务发执行的事务

Reed Reed ’’lawlaw (瑞德(瑞德定律):效益规模是定律):效益规模是O(2O(2nn)) :网络是群组:网络是群组媒介。网络可建立媒介。网络可建立CnCn22+Cn+Cn33++……CnCnnn--1+Cn1+Cnnn = 2 = 2nn-n-1 -n-1 个个小组小组

Network service scale rules

Page 10: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Problem

• Client-Server and Web architectures are inherently centralized.

• Some problems involve distributed control, distributed data, or a hierarchical organizational structure.

• Fitting a centralized solution to a decentralized problem makes a poor solution.

Thick Thick ClientClient

Thick Thick ClientClient

ServerServer

Thin ClientThin Client

Web ServerWeb Server

Database Database ServerServer

Middle TierMiddle Tier

BrowserBrowserBrowserBrowser

Page 11: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

P2P Architecture

• P2P means actors in the system talk directly with each other as equals.

• Can decentralize some or all of the solution.• Represents distributed or hierarchical information

models.• Moves data and control to where the action is.

Page 12: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Definitions

Page 13: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Definitions of P2P

• Intel 工作组:通过在系统之间直接交换来共享计算机资源和服务的一种应用模式

• R.l.Granham: 通过 3 个关键条件定义• 具有服务器质量的可运行计算机• 具有独立于 DNS 的寻址系统• 具有与可变连接合作的能力

• C.Shirky:• 利用因特网边界的存储 /CPU/ 内容 / 现场等资源的一种应用• 访问这些非集中资源意味着运行在不稳定连接和不可预知 IP 地址环境下, P2P

节点必须运行在 DNS 系统外边• 具备有效或全部的自治

• Milojicic et al. (HP) : P2P refers to a class of systems and applications that employ distributed resources to perform a critical function in a decentralized manner.

Page 14: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Controversy

• Is p2p a new approach?

Problems is peer-to-peer systems are neither new nor unique; they make us look for solutions

to old problems that we all worked around or tried to ignore before.

Andy Oram (O'Reilly & associates)speech at Free and Open Source

Software Developers's MeetingBrussels, BE, Feb. 2002

Page 15: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

P2P based applications

Page 16: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Examples of p2p usage

• File-sharing applications• Distributed databases• Distributed computing (grid?)• Collaboration• Distributed games• Instant messaging• Ad hoc networks• Application-level multicast• Etc.

Page 17: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Peer-to-Peer Systems

Page 18: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Interesting P2P Applications

• Gnutella for dictionaries (with supernode)• Worldwide Lexicon, http://picto.weblogger.com

• Infrastructure for interoperability• Edutella (RDF-based Metadata Infrastructure),

http://edutella.jxta.org/

• Global-scale storage• Oceanstore, http://oceanstore.cs.berkeley.edu/

• Payments (not involving a bank)• PayPal (more than 0.4 billion accounts, payment

volume 15B/year per year, profit 230M/year)• eCount.com (email payment)

Page 19: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Interesting P2P Applications

• Instant Messaging• Jabber, http://www.jabber.org/• Skype, http://www.skype.com

• VoIP (good quality, latency and 256-bit encry, NAT/firewall traversal)• Skype , www.skype.com/

• Groupware• Groove, http://www.groove.net/

• FOAF (Friends-of-a-Friend)• FOAFNaut, http://www.foafnaut.org/ • Friends Reunited, http://www.friendsreunited.com/ • Orkut, http://www.orkut.com/ • Tribe.net, http://www.tribe.net/

• Application-layer multicast• PPlive,QQlive

Page 20: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Interesting P2P Applications

• 虚拟超级计算机 peer-to-peer technology 产生空前大量的计算能力

• 使医疗研究者能加速治疗方法的改进和药物的设计

• 加快癌研究的新发现

http://www.stanford.edu/group/pandegroup/Cosm/

http://members.ud.com/vypc/cancer/

Folding@home/ 蛋白质折叠和药物设计

Site@home/ 寻找地外文明计划http://www.equn.com/seticn/

Page 21: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

P2P Structure

Page 22: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

P2P Overlay Network structure

• Unstructured• Without prior knowledge

of the topology• Flooding

• Freenet• Gnutella• FastTrack/KaZaA• BitTorrent• Overnet/eDonkey

• Structured• Topology is tightly

controlled• DHT (distributed hash

table)

• CAN• Chord• Tapestry• Pastry• Kademlia• Viceroy

hybrid

Page 23: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Centralized model (Napster)

• File-sharing system• Almost distributed system

• The location of a document is centralized• The "transfer" is peer-to-peer

• Problems• Robustness• Scalability (?)

• Impacts• Lawsuits• Denial of service

INTERNET

locationserver

register

Document x?OK: Peer ZIP = a.b.c.d

Document x!

x

Page 24: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Non-structured system (Gnutella-like)

• Two phases (like Napster)• Localization + exchange

• No server• Open source

• gnutella.wego.com

• Distributed search• The query is flooded• Loop avoidance• Limited TTL (not all nodes are visited)

1

1

2

34

1

5

Page 25: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Freenet

• Anonymity• Replication, cache

• Routing• Local knowledge• cache• TTL limits search

Page 26: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

FastTrack/KaZaA

5

3

2

11

4

metadata

metadata

Supernodes still use a broadcast protocolforsearch.

Page 27: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Related work: Skype From the KaZaA community

• Promote to super nodes• Peer cache of some super nodes• Based on availability, capacity

• Protocol among super nodes: ???• Other features

• Auto-detect NAT/firewall settings• Allows searching a user (e.g., kun*)• History of known buddies• All communication is encrypted• Conferencing

P

P

P

P

PP

PP

P

P P P

Page 28: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

BitTorrent

seed

url

The tracker keeps track of all the owners and lookup peers.

Page 29: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Why structured?

• Query time, number of messages,network usage, per node state, etc.

Unstructured

P2P systems

Structured

Data availability• Decentralization• Scalability• Load balancing• Fault tolerance

Maintenance• Join/leave• Repair

Efficient searching• Proximity• Locality

• If present => find it• Flooding: not scalable• Blind search: inefficient

Core facility—DHT ( Distribute Hash Tables )

Page 30: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

General concepts of DHTs

• Every object has a (hash) key• An object is stored at the node responsible for its

key• Every node maintains a small routing (hash) table

consisting of its neighboring nodes• All DHTs provide one elementary function

• lookup(key) node

Page 31: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

The role of DHT in structured P2P

Page 32: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Chord lookup

Page 33: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Chord lookup w/ finger table

id-space = 2m

m = 6

size = m

Page 34: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Challenges

Page 35: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Technical Challenges of P2P

• Decentralization• Control• Security• Sustainability• Management

Page 36: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Decentralization

• Fully decentralized means every peer is an equal participant and no peers have special or administrative abilities

• Fully decentralized is difficult and many P2P systems are hybrids

• Decentralization is a tool, not a goal• Centralize the parts that need to be fast and need

to scale• Decentralize the parts required by the problem

model

Page 37: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Control

• Myth: P2P has no control over their systemsTruth: P2P has no central control, but each peer is constrained by its own rules

• Myth: P2P systems must rely on honor system and are prone to malicious usersTruth: P2P systems have a design tradeoff, openess vs. susceptibility

• Myth: There is no way to control the data in a P2P systemTruth: No one has super-user access to the data. But users control the data they create.

• Myth: P2P has anonymous users with no accountabilityTruth: Mechanisms like pseudonyms allow anonymity while enforcing accountability

• Myth: P2P systems can’t exclude known malicious usersTruth: Decentralized user access is possible but tricky

Page 38: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Security

• P2P applications can be made secure much like the IP protocol

• Encryption can ensure that a file is unread and unmodified even if it passes through the control of malicious peers (eg. Freenet)

• Data’s origin can be ensured even though anyone can add data to the system (eg. Groove)

Page 39: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Sustainability

• You need a cool idea and a critical mass• System must be easy to use• Normal use of the system needs to contribute to

the system • Imposition on users must be things they don’t mind

Page 40: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Managemnet

• Selfishness• Equitableness• Impact to IP networks• Copyright and laws

Page 41: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Platform and tools

Page 42: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Jini – a service broker

• Jini is a Java-based service toolkit• Provides service broker called Jini Lookup Service• Provides discovery and notification API• Service stubs passed to requester

Jini Lookup Service

ServiceRequester

Jini ServiceProvider 1

Jini ServiceProvider 2

Jini ServiceProvider 3

Need service X with attribute A

Service XAttributes: B, D

Service YAttributes: C

Service XAttributes: A, D

ServiceProvider 3

Page 43: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

JXTA (Sun)

• Open platform for p2p cooperation

• Interoperability• Any system/peer/application

• Platform independency• Languages (C, Java, etc)• Systems platforms (Unix, Windows, etc)• Networking platforms (802.11, Bluetooth, TCP/IP, etc)

• Ubiquity• Sensors, PDAs, routers, desktops, laptops, storage

systems

Page 44: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

JXTA (Sun)

• Objectives• Find peers and resources• Share files with anyone across the network • Create a particular group of peers across different

networks • Communicate securely with peers across public networks

• Projects• Applications (24 projects)• Core (13 projects)• Demos (3 projects)• Forge (15 projects)• Other (12 projects)• Services (24 projects)

Page 45: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

JXTA (Sun) Protocols

• Peer discovery protocol• Peer resolver protocol• Peer information protocol• Pipe binding protocol• Endpoint routing protocol• ……

Page 46: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

JXTA (Sun)

Peer (Desktop, cell phone, PDA, etc.)

Security

Peer Groups Peer Pipes Peer Monitoring

JXTA Community ServicesSun JXTAServices

JXTAShell

PeerCommands

JXTA Community Applications

CORE

JXTA

Page 47: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

JXTA applications

Page 48: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

PlanetLab

• Testbed to experiment with your networked applications. • >400 nodes, >150 sites, • PlanteLab consortium: 80+ universities, Intel, HP

• View presented to users: a distributed set of VMs• Allocation unit: a slice = a set of virtual machines (VM),

one VM at each node.

452 nodes162 sites450 research projects

VMM VMM VMM VMM

S

lice

K

OS S

lice

K

OS S

lice

K

OS S

lice

K

OS

http://www.planet-lab.org/

Page 49: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

PlanetLab usage examples

• Stress-test your Grid services (Globus RLS)• GSLab: a playground to experiment with grid-services • ‘Better-than-Internet’ services:

• Resilient Overlays • Multipath TCP (mTCP)• Multicast Overlays

VMM VMM VMM VMM

OS

OS

OS

OS

Use

r ac

coun

t

Use

r ac

coun

t

Use

r ac

coun

t

Use

r ac

coun

t

Page 50: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Conclusions

Page 51: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Reviews

• P2P solutions can fit the problem model better than client-server or web solutions

• P2P solutions can do some cool things• P2P solutions can be production quality, but have

different issues than client-server or web solutions• It is not hard to code a P2P solution• Interesting application • Big challenge

Page 52: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Final remarks

• P2P implies a very large spectrum of areas• High interest in both academicals/industrials• Much has already been done, but no conclusions

are definitive• IPv6 and P2P

• NAT, firewalls, IPv6 as an overlay

• Many open issues• Trust, security, scalability, QoS, etc.

Page 53: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

P2P related research in future

安全和保护诚信匿名声誉

智能代理 /Web-based 服务

比赛安排服务描述

网络结构和设计Network Topology

RoutingOverlay Networks

分布式数据库查询分解查询分布

仲裁

P2P

社会人际小世界现象

Power-Law 网络

商业和法律问题商业模式知识产权

分布式数据结构分布式 Hash 表

可扩展分布式数据

网络结构和设计网络拓扑路由

重叠网络

可扩展路由和对象可扩展路由和对象定位定位

性能提高性能提高 语义重叠网络语义重叠网络 P2PP2P 算法算法 复制复制 基于基于 WebWeb 的信息的信息

搜索搜索 激励和公平激励和公平 隐私隐私 // 安全安全 // 诚信诚信

Page 54: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

What can we learn from P2P?

Page 55: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

P2P 系统实例研究摘要 ----- 系统特点

分类 可选解 平台 语言 / 工具 不同点 网络

Avaki 分布式计算

单装置 HPC超级计算

Linux, WinSolaris

OO,ParalFort.Ada,C

分布管理、异质、安全高并

因特内网

SETI@home 分布式对象 所有通用OS

Closed source 大规模 因特

Groove

协同

Web-Based协同

Windows JavaScript,VB,Perl,C++,XML 回放、自更新 因特内网

Magi 分布文件聊天 / 消息

WindowsMac

Java,XML,HTTP,WebDAV

基于 HTTP平台独立

因特Ad-hoc

Freenet内容共享

匿名可信单点

Any withJava

Java 实现和 APIs 匿名保存 因特

Gnutella 中心服务 WindowsLinux

Java,C 协议 因特

JXTA平台

C/S Solaris Linux, Win

Java,C,Perl 开发源码 因特

.NET/My Service

Web-Based Windows C#,VC++,JScripVBScrip,VB

基于 MS 应用 因特移动

Page 56: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

P2P系统

实例特点比较研究 -------- 系统特点

非集中化 可扩展性 匿名 自组织 权成本

Ad-hoc 性能 安全 透明性 容错 交互

Avaki 无中心 1000测 2-3千

N/A 失效重构 低 进出计算资源 加速 加密认证管理域

本地HW/SW异质

校验重启可靠报文

同 SUN网格

SETI@home

主从 百万 中 低 很低 进出计算资源 大加速 私有 高 定时校验 IP?

Groove 混合P2P

N/A 差 高 低 协同进出

中 共享空间 /认证授权

高 消息进队列

基于 IP

Magi 混合P2P

约 100 N/A N/A 低 伙伴进出

N/A 证书授权 离线伙伴通信

消息进队列

JXTA/WEebD

AV

Freenet 纯 P2P 理论LogN

高 高 低 Peers 的进出 中 匿名 / 防DOS

高 无单点故障

Gnutella 纯 P2P 千 低 高 低 Peers 的进出 低 不明 中 再用下载 IP?

JXTA 纯 P2P 嵌入式系统

N/A N/A 低 Peers 的进出 N/A 加密算法 / 分布

信任

低 低 低

.NET/My 混合 世界范围 N/A 中 低 Peers 的进出 高 基于护照 高 复制 SOAP/XML/UDDI/WSDL

Page 57: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

P2P系统

实例商业模式的比较研究 ----- 系统特点

收入模式 支持应用 知名用户 竞争者 基金 商业模式

Avaki 产品和开放源码 计算网格共享安全数据

无 /科学实验室评价

平台计算Globus

Startup N/A

SETI@home

学术研究 关闭 学术 cancer@home...

政府 售机加屏保

Groove 产品 进销存 N/A Magi IPO 选 Lotus协同工具

Magi 产品和开放源码 共享文件消息聊天 全球 e 技术媒体软

Groove Startup N/A

Freenet 开放源码 文件共享 公共 N/A Startup N/A

Gnutella 开放源码 文件共享 公共 N/A 公共领域 选 P2P 算法

JXTA 开放源码& 所有权扩展

文件共享事件通知 多 P2P端口到 NET/Myservice

Sun支持的公域

公用 P2P 平台

.NET/My 所有权 & 开放源码标准

微软办公其它 MS 大基数 AOL/J2EE/JXTA

MS 内部 普适平台

Page 58: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

系统和应用需求

解决方案比较 1---- 系统类型

Centralized C/S Peer to Peer

非集中化 低(无) 高 很高

Ad-hoc 行为 无 中 高

产权成本 很高 高 低

匿名 低(无) 中 很高

可扩展性 低 高 高

性能 单独高聚合低 中 单独低聚合高

容错 单独高聚合低 中 单独低聚合高

自组织 中 中 中

透明性 低 中 中

安全 很高 高 低

交互性 标准化 标准化 正在进行

Page 59: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

目标 标准 解决方案比较 2---- 系统类型Centralized C/S P2P

用户普适性 低 中 高技术水平 低 高 中

复杂性 高 低 中信誉声望 高 中 低

开发者复杂性 高 直接 典型- N0

支撑能力 低 高 中工具 中(私有) 高-标准 低(少)兼容性 中 高 低

IT记帐能力 高 中 低

在控 高(全) 中 低管理能力 中 高 低标准 中(私有) 高 低(无)

Page 60: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Main references

• Eng Keong Lua et al. “A Survey and Comparison of Peer-to-A Survey and Comparison of Peer-to-Peer Overlay Network SchemesPeer Overlay Network Schemes,” IEEE Communications Surveys and Tutorials, Vol 7, No 2 (Second Quarter, 2005), pp. 72-93.

• Ion Stoica, Robert Morris, et al. “Chord: A Scalable Peer-to-Chord: A Scalable Peer-to-peer Lookup Service for Internet Applicationspeer Lookup Service for Internet Applications,” Proceedings of ACM SIGCOMM 2001, San Deigo, CA, August 2001, pp. 149-160.

• Diego Doval and Donal O’Mahony, “Overlay networks: a Overlay networks: a scalable alternative for P2Pscalable alternative for P2P,” IEEE Internet Computing, Vol 7, No 4 (July-August 2003), pp. 79-82.

Page 61: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

References

• Distributed Computing• Distributed (www.distributed.net)• SETI@home (www.seti.org)• Genome@home (gah.stanford.edu)• Folding@home

(www.stanford.edu/group/pandegroup/folding)• Global Grid Forum (www.globalgridforum.org)• Globus Project (www.globus.org)

• File sharing• Napster (www.napster.com)• Gnutella (gnutella.wego.com)• Kazaa (www.kazaa.com)

Page 62: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

References

• Distributed hash tables• CAN (www.acm.org/sigs/sigcomm/sigcomm2001/p13-

ratnasamy.pdf)• Pastry (research.microsoft.com/~antr/Pastry)• Chord (www.pdos.lcs.mit.edu/chord)• Tapestry (www.cs.berkeley.edu/~ravenben/tapestry)• Freenet (freenet.sourceforge.net)• Kademlia (kademlia.scs.cs.nyu.edu)

• Ad hoc networking• AODV (www.ietf.org/internet-drafts/draft-ietf-manet-

aodv-13.txt)• OLSR (www.ietf.org/internet-drafts/draft-ietf-manet-olsr-

10.txt)• Tribe (rp.lip6.fr/site_rp/_publications/350-79Viana.ps.gz)

Page 63: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

References

• Platforms • JXTA (www.jxta.org)• .NET (www.microsoft.com/net)

• Collaboration• Groove (www.groove.net)• Endeavors (www.endeavors.com)

• IPv6 as a p2p overlay• Working Groups

• p2p.internet2.edu• www.openp2p.com

Page 64: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Slides borrowed

• Chord: A Scalable Peer-to-peer Lookup Service for Internet Applicationshttp://pdos.csail.mit.edu/~rtm/slides/sigcomm01.ppt

• P2P-SIP: Peer to peer Internet telephony using SIPhttp://www1.cs.columbia.edu/~kns10/research/p2p-sip/

Page 65: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Working groups et al.

• A generic site on p2p from O'Reilly• www.openp2p.com

• P2P working group• www.peer-to-peerwg.org/

• Internet2 p2p working group• p2p.internet2.edu

• Peer-to-peer development (p2p-hackers)• zgp.org/mailman/listinfo/p2p-hackers

• Interesting meeting• www.codecon.org

Page 66: Peer-to-Peer(P2P) Zhenxiang CHEN Network Center of Jinan University czx@ujn.edu.cn

Reading

• CAN• Chord

• Tapestry• Pastry