DOCSLIB.ORG

CS 580 Client-Server Programming Fall Semester, 2000 Doc 26 Tiers & Peers Contents How Many Tiers?

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
CS 580 Client-Server Programming Fall Semester, 2000 Doc 26 Tiers & Peers Contents How Many Tiers? 12/6/00 Doc 26, Tiers & Peers slide # 1 CS 580 Client-Server Programming Fall Semester, 2000 Doc 26 Tiers & Peers Contents How many Tiers? ............................................................................................... 2 Client Presentation ............................................................................................. 3 Peer-to-Peer....................................................................................................... 4 Gnutella........................................................................................................... 5 Multicast Sockets ............................................................................................ 7 Bluetooth......................................................................................................... 8 References Overview of Two- and Three-Tier Client/Server Architectures Gartner Report, via Governor's Office for Technology, Kentucky, about 1998 http://cdc.state.ky.us/dcs/tiers.htm Gnutella news http://www.gnutellanews.com/ http://gnutella.wego.com/ Gnutella Protocol 0.04 http://dss.clip2.com/GnutellaProtocol04.pdf Gnutella: To the Bandwidth Barrier and Beyond, November 6, 2000 http://dss.clip2.com/gnutella.html Wired P2P Pages, Lists of clients, protocols, etc http://www.wired.com/wired/archive/8.10/p2p_pages.html?pg=1 Independence Array, Jermoe Kuptz, Wired October, 2000, pp. 236-237 Java Network Programming 2nd Ed, Harold, O'Reilly, 2000, chapter14 Bluetooth Web site http://www.bluetooth.com/ Copyright ©, All rights reserved. 2000 SDSU & Roger Whitney, 5500 Campanile Drive, San Diego, CA 92182-7700 USA. OpenContent (http://www.opencontent.org/opl.shtml) license defines the copyright on this document. 12/6/00 Doc 26, Tiers & Peers slide # 2 Odds & Ends How many Tiers? Typical business application is claimed to have: · Presentation or Display logic & user interaction · Business rules · Data access Three Tier Client handles presentation Server handles business rule Server gets data from database Two Tier Client handles presentation and perhaps business rules Server handles data access and perhaps business rules Thin client only handles presentation Thick client also handles business rules Four Tier Presentation Flow control functions Business rules Data access logic 12/6/00 Doc 26, Tiers & Peers slide # 3 Client Presentation To the user the client is the application If the user does not like the interface, they do not like the application See User Interface Design for Programmers an on-line book for user interface design at: http://joel.editthispage.com/stories/storyReader$51 The client is not just a way to send the protocol to the server 12/6/00 Doc 26, Tiers & Peers slide # 4 Peer-to-Peer Back to the future Peer-to-peer Clients communicate with other clients directly Clients are also servers Why peer-to-peer Environments that do not have dedicated servers Lack of system administrator Ad-hoc networks Wireless mobile computers Avoid central control Some examples AppleTalk networks Gnutella Bluetooth 12/6/00 Doc 26, Tiers & Peers slide # 5 Gnutella Created by Justin Frankel & Tom Pepper at AOL's Nullsoft Posted for a few hours on March 14 2000 The protocol was reversed-engineered Many clones now exist Gnutella is a file-sharing program User lists files to share with their gnutella client When the client is running other gnutella clients can request copies of your files 12/6/00 Doc 26, Tiers & Peers slide # 6 How it works Gnutella client starts with locations N other clients Each client answers the request and sends it on to all clients it knows TTL (time to live) Number of times a request will be forwarded to another client Maximum TTL is 7 Radius - the clients that are within 7 hops A radius can have up to 10,000 clients Protocol does not scale well, but works better than some thought possible See Gnutella: To the Bandwidth Barrier and Beyond, November 6, 2000 http://dss.clip2.com/gnutella.html for a report on growth of Gnutella networks 12/6/00 Doc 26, Tiers & Peers slide # 7 Multicast Sockets Unicast sockets · Provide point-to-point communication · Client needs to know server address Multicast sockets · Each multicast address is a group of hosts · Hosts can leave/join the group dynamically · Packets are sent to all hosts in the group · TTL of packet indicates how far a packet will be sent Jini uses multicast · Jini network is an ad-hoc network of services & clients · Services use multicast to find a naming service (broker) · Clients use multicast to find a naming service to find services See http://www.eli.sdsu.edu/courses/spring99/cs696/notes/jiniIntro/j iniIntro.html and http://www.sun.com/jini/index.html for more info on Jini 12/6/00 Doc 26, Tiers & Peers slide # 8 Bluetooth Wireless ad-hoc network standard Radio Specs Range 10 meters Frequency band 2.4 Ghz Max Data transfer721kbit/s + 3 voice channels Packet switching protocol with frequency hopping 1600 hops/second Piconet · Up to 7 devices connected by radio Multiple piconets can be linked together dynamically Uses error correction and encryption Started by Ericsson, IBM, Intel Corporation, Nokia and Toshiba in 1998 Has wide spread industry support More popular in Europe.
Load more

Recommended publications
  • Peer-To-Peer Systems and Massively Multiplayer Online Games
    Peer-to-Peer Systems and Massively Multiplayer Online Games Speaker: Jehn-Ruey Jiang CSIE Department National Central University P2P Systems Client/Server Architecture GET /index.html HTTP/1.0 HTTP/1.1 200 OK ... Server Clients 3/66 Peer-to-Peer Architecture Gateway Server Peers 4/66 The architectures Server-based architecture Client-Server / Server-Cluster Problems： Limited resources All loads are centered on the server Server-based architecture has low scalability. The setup and maintenance cost is high. Peer-to-Peer (P2P) architecture Advantages： Distributing loads to all users Users consume and provide resources P2P architecture has high scalability. The setup and maintenance cost is low. The Client Side Today‟s clients can perform more roles than just forwarding users requests Today‟s clients have: more computing power more storage space Thin client Fat client 6/66 Evolution at the Client Side DEC‟S VT100 IBM PC PC @ 4-core 4GHz @ 4.77MHz No storage 300GB HD 360k diskettes „70 „80 2008 7/66 What Else Has Changed? The number of home PCs is increasing rapidly Most of the PCs are “fat clients” As the Internet usage grow, more and more PCs are connecting to the global net Most of the time PCs are idle How can we use all this? Peer-to-Peer (P2P) 8/66 What is peer-to-peer (P2P)? “Peer-to-peer is a way of structuring distributed applications such that the individual nodes have symmetric roles. Rather than being divided into clients and servers each with quite distinct roles, in P2P applications a node may act as both
    [Show full text]
  • 04. Peer-To-Peer Applications
    Internet Technology 04. Peer-to-Peer Applications Paul Krzyzanowski Rutgers University Spring 2016 February 15, 2016 CS 352 © 2013-2016 Paul Krzyzanowski 1 Peer-to-Peer (P2P) Application Architectures • No reliance on a central server • Machines (peers) communicate with each other • Pools of machines (peers) provide the service • Goals client server – Robustness • Expect that some systems may be down – Self-scalability • The system can handle greater workloads as more peers are added peers February 15, 2016 CS 352 © 2013-2016 Paul Krzyzanowski 2 Peer-to-Peer networking “If a million people use a web site simultaneously, doesn’t that mean that we must have a heavy-duty remote server to keep them all happy? No; we could move the site onto a million desktops and use the Internet for coordination. Could amazon.com be an itinerant horde instead of a fixed central command post? Yes.” – David Gelernter The Second Coming – A Manifesto See http://edge.org/conversation/the-second-coming-a-manifesto February 15, 2016 CS 352 © 2013-2016 Paul Krzyzanowski 3 Peer to Peer applications • P2P targets diverse solutions – Cooperative computation – Communications (e.g., Skype) – Exchanges, digital currency (bitcoin) – DNS (including multicast DNS) – Content distribution (e.g., BitTorrent) – Storage distribution • P2P can be a distributed server – Lots of machines spread across multiple datacenters Today, we’ll focus on file distribution February 15, 2016 CS 352 © 2013-2016 Paul Krzyzanowski 4 Four key primitives • Join/Leave – How do you join a P2P system?
    [Show full text]
  • You Are Not Welcome Among Us: Pirates and the State
    International Journal of Communication 9(2015), 890–908 1932–8036/20150005 You Are Not Welcome Among Us: Pirates and the State JESSICA L. BEYER University of Washington, USA FENWICK MCKELVEY1 Concordia University, Canada In a historical review focused on digital piracy, we explore the relationship between hacker politics and the state. We distinguish between two core aspects of piracy—the challenge to property rights and the challenge to state power—and argue that digital piracy should be considered more broadly as a challenge to the authority of the state. We trace generations of peer-to-peer networking, showing that digital piracy is a key component in the development of a political platform that advocates for a set of ideals grounded in collaborative culture, nonhierarchical organization, and a reliance on the network. We assert that this politics expresses itself in a philosophy that was formed together with the development of the state-evading forms of communication that perpetuate unmanageable networks. Keywords: pirates, information politics, intellectual property, state networks Introduction Digital piracy is most frequently framed as a challenge to property rights or as theft. This framing is not incorrect, but it overemphasizes intellectual property regimes and, in doing so, underemphasizes the broader political challenge posed by digital pirates. In fact, digital pirates and broader “hacker culture” are part of a political challenge to the state, as well as a challenge to property rights regimes. This challenge is articulated in terms of contributory culture, in contrast to the commodification and enclosures of capitalist culture; as nonhierarchical, in contrast to the strict hierarchies of the modern state; and as faith in the potential of a seemingly uncontrollable communication technology that makes all of this possible, in contrast to a fear of the potential chaos that unsurveilled spaces can bring.
    [Show full text]
  • Kent State University
    FOUNDATION OF PEERPEER--TOTO--PEERPEER SYSTEMS A Course on Foundations of PeerPeer--toto--PeerPeer Systems & Applications LECT-07, S-1 FP2P08S, [email protected] Javed I. Khan@2008 CS 6/75995 Kent State Foundation of PeerPeer--toto--PeerPeer University Applications & Systems Dept. of Computer Science www.cs.kent.edu/~javed/classwww.cs.kent.edu/~javed/class--P2P08/P2P08/ LECTLECT--77 2 1 FOUNDATION OF PEERPEER--TOTO--PEERPEER SYSTEMS Vibrant Systems: Gnutella Family LECT-07, S-3 FP2P08S, [email protected] Javed I. Khan@2008 Classification [*Eberspacher & Schollmeier 2005] FOUNDATION OF Client-Server Peer-to-Peer PEERPEER--TOTO--PEERPEER SYSTEMS 1. Server is the central 1. Resources are shared between the peers entity and only 2. Resources can be accessed directly from other peers provider of service 3. Peer is provider and requestor (Servent concept) and content. Network managed Unstructured P2P Structured P2P by the Server Centralized P2P Pure P2P Hybrid P2P DHT-Based 2. Server as the higher performance system. 1. All features of Peer-to- 1. All features of Peer-to- 1. All features of Peer-to- 1. All features of Peer-to- Peer included Peer included Peer included Peer included 3. Clients as the lower performance system 2. Central entity is 2. Any terminal entity can 2. Any terminal entity can 2. Any terminal entity can necessary to provide the be removed without loss be removed without loss be removed without loss service of functionality of functionality of functionality Example: WWW 3. Central entity is some 3. No central entities 3. dynamic central 3. No central entities kind of index/group Examples: Gnutella 0.4, entities 4.
    [Show full text]
  • Get Real: Print This
    Get Real: Print This http://www.corante.com/getreal/archives/032237print.html from Get Real by Marc Eisenstadt January 11, 2005 BitTorrent, eXeem, Meta-Torrent, Podcasting: "What? So What?" SUMMARY: The index that facilitates the sharing of files on a large scale is also the Achilles heel of peer-to-peer file-sharing, because it is vulnerable to litigation and closure. So what happens if the index is itself distributed? I try to get my head around the latest in peer-to-peer file sharing, and explain a bit about what I've learned, including the fact that BitTorrent's power rests in its 'swarm' distribution model, but not necessarily in your end-user download speed. What has this got to do with podcasting? (Answer: invisible P2P plumbing helps the podcasting wheel go round). [Warning: lengthy article follows]. First, some history (skip ahead to the next section if you're already bored with the Napster, Gnutella, KaZaa, and BitTorrent saga). Napster opened our eyes to the power of distributed file sharing on a massive scale. But it was closed down by lawsuits to stop it from listing copyrighted works for which the owners would naturally have preferred to collect royalties (there are thousands of commentaries on the pros and cons of such royalties, but that's not the focus of this posting). Successive generations of tools such as Gnutella, KaZaa, and now BitTorrent have created their own buzz, their own massive followings, their own headaches, and their own solutions to others' headaches. Here's my rundown of the 'big ideas' (and the people behind them): Napster (Shawn Fanning): This was the Mother of big-time peer-to-peer (P2P) file transfers, i.e.
    [Show full text]
  • Title: P2P Networks for Content Sharing
    Title: P2P Networks for Content Sharing Authors: Choon Hoong Ding, Sarana Nutanong, and Rajkumar Buyya Grid Computing and Distributed Systems Laboratory, Department of Computer Science and Software Engineering, The University of Melbourne, Australia (chd, sarana, raj)@cs.mu.oz.au ABSTRACT Peer-to-peer (P2P) technologies have been widely used for content sharing, popularly called “file-swapping” networks. This chapter gives a broad overview of content sharing P2P technologies. It starts with the fundamental concept of P2P computing followed by the analysis of network topologies used in peer-to-peer systems. Next, three milestone peer-to-peer technologies: Napster, Gnutella, and Fasttrack are explored in details, and they are finally concluded with the comparison table in the last section. 1. INTRODUCTION Peer-to-peer (P2P) content sharing has been an astonishingly successful P2P application on the Internet. P2P has gained tremendous public attention from Napster, the system supporting music sharing on the Web. It is a new emerging, interesting research technology and a promising product base. Intel P2P working group gave the definition of P2P as "The sharing of computer resources and services by direct exchange between systems". This thus gives P2P systems two main key characteristics: • Scalability: there is no algorithmic, or technical limitation of the size of the system, e.g. the complexity of the system should be somewhat constant regardless of number of nodes in the system. • Reliability: The malfunction on any given node will not effect the whole system (or maybe even any other nodes). File sharing network like Gnutella is a good example of scalability and reliability.
    [Show full text]
  • Essay the Evolution and Revolution
    Essay The Evolution and Revolution of Napster* By PETER JAN HONIGSBERG** As I TURNED the corner onto Seventh Street from Mission Street in San Francisco on that Monday morning, October 1, 2000, I knew I was watching history unfold. The satellite dishes, the neon-bright lights set atop the media vans, and members of the press fidgeting anxiously had replaced the homeless who usually encamp near the main en- trance to the Federal Court of Appeals building. As many as two hun- dred members of the national and international media had arrived that day, some as early as 4:15 A.M., although the music industry's law- suit against Napster was scheduled to begin at 11:00 A.M.I A television reporter was interviewing a balding man in a blue striped suit, the artificial lamps barely making a dent in the gray, dull natural light. I. Piracy-the Word of the Day While I watched the reporters lining up at the door to the court- house, I could not help but see the "P" word flashing overhead. The five major record companies ("the majors") and the Recording Indus- try Association of America ("RIAA")-the association that represents the companies-had paid their publicity agents and lawyers well. Piracy was the word of the day. Actually, at least where Napster was concerned, it was the word of the entire millennium year of 2000, and continued to be the word after the Ninth Circuit issued its unanimous * Just like the technology upon which this essay is based, the essay itself will be out of date the moment the typing stops.
    [Show full text]
  • Ahistory of ONLINE GATEKEEPING
    Harvard Journal of Law & Technology Volume 19, Number 2 Spring 2006 A HISTORY OF ONLINE GATEKEEPING Jonathan Zittrain* TABLE OF CONTENTS I. INTRODUCTION..............................................................................253 II. TWO KINDS OF GATEKEEPERS .....................................................254 III. EARLY APPLICATIONS OF GATEKEEPING ONLINE: SUPPLEMENTS TO EXISTING PRIVATE MONITORING AND ENFORCEMENT REGIMES ..............................................................257 IV. LIMITED GATEKEEPING CONTINUES AS THE INTERNET MATURES: COPYRIGHT INFRINGEMENT, ISPS, AND OSPS............263 V. LIMITED GATEKEEPING IS TESTED AS THE INTERNET DEVELOPS FURTHER: COPYRIGHT INFRINGEMENT, PEER- TO-PEER SERVICES, AND RENEWED CONSIDERATION OF DUTIES TO PREEMPT OR POLICE ...................................................271 VI. GATEKEEPING ON THE GRID: GROKSTER AS FORBEARANCE..............................................................................286 VII. THE END OF REGULATORY FORBEARANCE?: FROM KRAAKMAN’S GATEKEEPERS TO LESSIG’S GATEKEEPERS ...........294 VIII. CONCLUSION............................................................................298 I. INTRODUCTION The brief but intense history of American judicial and legislative confrontation with problems caused by the online world has demon- strated a certain wisdom: a reluctance to intervene in ways that dra- matically alter online architectures; a solicitude for the collateral damage that interventions might wreak upon innocent activity; and, in the balance, a refusal
    [Show full text]
  • Improving Gnutella Protocol: Protocol Analysis and Research Proposals
    Improving Gnutella Protocol: Protocol Analysis And Research Proposals Igor Ivkovic Software Architecture Group (SWAG) Department of Computer Science University of Waterloo Waterloo, Ontario N2L 3G1 Canada +1 (519) 888-4567 x3088 [email protected] ABSTRACT phenomenon called Napster [1]. Fanning envisioned This paper presents an analysis of the Gnutella protocol, a Napster as a service that allows users of his system to list type of the peer-to-peer networking model, that currently the MP3-encoded music files that they are willing to share provides decentralized file-sharing capabilities to its users. and let other users download them through the Napster The paper identifies the open problems that are related to network. The central computer would then at all times have the protocol and proposes strategies that can be used to an up-to-date master list of files that people are willing to resolve them. share, and the list would be updated by the users’ software as they log on and off the system. Initially, the paper explains the basics of the peer-to-peer networking, and then compares the two types of this Fanning’s idea required an network infrastructure of networking standard: centralized and decentralized. The servers for the centralized peer-to-peer data access and data Gnutella protocol is classified as a decentralized model, storage, and a corresponding bandwidth for allowing a and its characteristics and specifications are described large number of user connections. After his idea is accordingly. implemented, Napster at one point attracted over 30 million users with over 800 thousand of them accessing the The issues that are outstanding for the protocol are listed network simultaneously [1].
    [Show full text]
  • Shoutcast Audio and Video Streaming Guide
    SHOUTcast Audio And Video Streaming Guide Created By David Childers www.scvi.net Creative Common License This body of work is released under the Attribution-ShareAlike version 3.0, Creative Common License. The work may be freely distributed or modified for commercial or non commercial purposes. If this work is modified, compliance with the Attribution-ShareAlike version 3.0, Creative Common License is required. These requirements include: - Any derivatives of this work must be attributed to David Childers. - Alterations, transforming, or building upon this work requires distributing the resulting work only under the same, similar or a compatible license. For the complete legal code, please refer here: www.creativecommons.org/licenses/by-sa/3.0/legalcode Front cover picture: Series modulator using two tetrodes. This image has been (or is hereby) released into the public domain by its author, Cadmium at the wikipedia project. This applies worldwide. http://en.wikipedia.org/wiki/File:Seriesmod.png About The Author David Childers is the Content Manager and Senior Editor for the International Broadcasting portal www.BroadcastingWorld.net. He is also the webmaster of the SHOUTcast video streaming information resource, www.scvi.net. He is very active in the Internet broadcast industry. Mr. Childers work has been cited in several national and International publications, such as: Five Essays on Copyright In the Digital Era Turrer Publishing Research On High-Profile Digital Video Production Digital Content Association of Japan Video Podcasting in Perspective: The History, Technology, Aesthetics and Instructional Uses of a New Medium Journal of Educational Technology Systems Video Podcasting: When, Where and How it's Currently used for Instruction The National Convention of the Association for Educational Communications and Technology IP Packet Charging Model For Multimedia Services National University of Rwanda Preservation of audiovisual mediums : Problems and challenges.
    [Show full text]
  • G T Ll Gnutella
    + = GtllGnutella What is Gnutella? • Invented March 2000 – byypp Justin Frankel and Tom Pepper • Peer-to-peer system • Became the first large-scale, fully decentralized system on the Internet • A message-based protocol • UTCPUses TCP Key ideas • Every node should interpret and respond to qqyueries as they wish • Allows more than one intelligence to be applied on the query Communication system • Message-based • Uses TCP broadcast • Time-to-live (TTL) = 7 (~10 000 nodes) • Decrements for each host the message passes • Excess traffic is simply forgotten How does it work? (1) • Ad hoc backbone – make nodes with fast network connections wander toward the centre of the network to handle the traffic • Create cells connected by high-speed backbone •Not gggpeographicall y How does it work? (2) • Response from green follows the same path back to blue • A direct HTTP connection is established between green and blue • Pseudo anonymity Traffic problems • Reflector – maintains an index of files stored on nodes to which it is connected (breaches key idea) • Host lists resulted in sparseness and small clusters • Host caches as startinggp point for Gnutella user – hand off a list of hosts you should connect to – tell new hosts about hosts theyyy saw recently – overcrowding Network problems (1) • Firewalls of NAT-devices • Solution: – PUSH REQUEST Network problems (2) • “Double firewall” – “arch enemyyp of productivity ” • No solution • PING packets with payload Windup • The first real P2P system • Message broadcasting • Lacking service discovery mechanism • Disastrous host caching programs • Pseudo anonymity and misuse • Problems related to firewalls, NAT-devices.
    [Show full text]
  • When Code Isn't Law
    Columbia Law School Scholarship Archive Faculty Scholarship Faculty Publications 2003 When Code Isn't Law Tim Wu Columbia Law School, [email protected] Follow this and additional works at: https://scholarship.law.columbia.edu/faculty_scholarship Part of the Intellectual Property Law Commons, and the Science and Technology Law Commons Recommended Citation Tim Wu, When Code Isn't Law, VIRGINIA LAW REVIEW, VOL. 89, P. 679, 2003; UNIVERSITY OF VIRGINIA SCHOOL OF LAW PUBLIC LAW & LEGAL THEORY RESEARCH WORKING PAPER NO. 03-10 (2003). Available at: https://scholarship.law.columbia.edu/faculty_scholarship/1290 This Working Paper is brought to you for free and open access by the Faculty Publications at Scholarship Archive. It has been accepted for inclusion in Faculty Scholarship by an authorized administrator of Scholarship Archive. For more information, please contact [email protected]. UNIVERSITY OF VIRGINIA SCHOOL OF LAW 2003 SPRING PUBLIC LAW AND LEGAL THEORY RESEARCH PAPERS SERIES WHEN CODE ISN’T LAW TIM WU WORKING PAPER NO. 03-10 This Paper Can Be Downloaded Without Charge From The Social Science Research Network Electronic Paper Collection Http://Ssrn.Com/Abstract_Id=413201 101 102 Virginia Law Review Vol. 89:nnn 2003] Compliance & Code 103 VIRGINIA LAW REVIEW VOLUME 89 JUNE 2003 NUMBER 4 ARTICLE WHEN CODE ISN’T LAW Tim Wu* INTRODUCTION...................................................................................104 I. A THEORY OF CODE, CHANGE, AND AVOIDANCE ...........................110 A. Reactions to Law in General Theories of Regulation .............110 B. When Groups Get Sick of Complying.....................................112 1. Avoidance Mechanisms ...................................................112 2. Change Mechanisms........................................................116 3. Summary: The Change/Avoidance Choice .......................118 C.
    [Show full text]