計(jì)算機(jī)網(wǎng)絡(luò) Internet 歷史 現(xiàn)狀與未來(lái)PPT課件

1、計(jì)算機(jī)網(wǎng)絡(luò)（Internet）歷史，現(xiàn)狀與未來(lái),計(jì)算機(jī)網(wǎng)絡(luò),Transportation service: move objects horse, train, truck, airplane . Communication network: move information bird, fire, telegraph, telephone, 計(jì)算機(jī)網(wǎng)絡(luò)Internet ,Communication networks can be classified based on the way in which the nodes exchange information:,A Taxonomy of

2、 Communication Networks,Communication Network,SwitchedCommunication Network,BroadcastCommunication Network 廣播，電視,Circuit-SwitchedCommunication Network 電話,Packet-SwitchedCommunication Network,Datagram Network,Virtual Circuit Network,Internet,The example,通話在 C 到 D (只經(jīng)過(guò)一個(gè)本地交換機(jī)) 的連接上進(jìn)行 通話在 A 到 B (經(jīng)過(guò)四個(gè)交換

3、機(jī)) 的連接上進(jìn)行 思考：電話交換對(duì)于計(jì)算機(jī)是否適合？ 效率/成本 應(yīng)用實(shí)時(shí),(,(,(,(,交換機(jī),交換機(jī),交換機(jī),交換機(jī),用戶線,用戶線,中繼線,中繼線,B,D,C,A,Circuit Switching （電路交換-電話）,A node (switch) in a circuit switching network,Circuit Switching: Multiplexing/Demultiplexing,Time divided in frames and frames divided in slots Relative slot position inside a frame de

4、termines which conversation the data belongs to Needs synchronization between sender and receiver In case of non-permanent conversations Needs to dynamic bind a slot to a conservation How to do this?,Timing in Circuit Switching,propagation delay between Host 1 and Node 1,propagation delay between Ho

5、st 2 and Node 1,報(bào)文,在發(fā)送端，先把較長(zhǎng)的報(bào)文劃分成較短的、固定長(zhǎng)度的數(shù)據(jù)段。,Packet Switching （分組/包交換） 1961,Computer networks self-development-packet switching,分組交換網(wǎng)以“分組”(也稱 包)作為數(shù)據(jù)傳輸單元 依次把各分組發(fā)送到接收端（假定接收端在左邊）。,Computer networks development-packet switching,最后，在接收端把收到的數(shù)據(jù)恢復(fù)成為原來(lái)的報(bào)文。 這里我們假定分組在傳輸過(guò)程中沒(méi)有出現(xiàn)差錯(cuò)，在轉(zhuǎn)發(fā)時(shí)也沒(méi)有被丟棄。,數(shù) 據(jù),數(shù) 據(jù),數(shù) 據(jù),Pack

6、et Switching （分組/包交換） 1961,Data are sent as formatted bit-sequences, so-called packets Packets have the following structure: Header and Trailer carry control information (e.g., destination address, check sum) Each packet is passed through the network from node to node along some path (Routing) At ea

7、ch node the entire packet is received, stored briefly, and then forwarded to the next node (Store-and-Forward Networks) Typically no capacity is allocated for packets,Router A,Router B,Router C,Router D,Router E,Packet Switching - Example,Router F,Timing of Datagram Packet Switching,Packet 3,Packet

8、3,Packet 1,Packet 2,Packet 1,Packet 2,Packet 1,Packet 2,Packet 3,processing delay of Packet 1 at Node 2,Host 1,Host 2,Node 1,Node 2,propagation delay between Host 1 and Node 2,transmission time of Packet 1 at Host 1,Packet Switching （分組/包交換） 1961,A node in a packet switching network,Packet Switching

9、: Multiplexing/Demultiplexing,Data from any conversation can be transmitted at any given time How to tell them apart? Use meta-data (header) to describe data Datagram Packet Switching Each packet is independently switched Each packet header contains destination address No resources are pre-allocated

10、 (reserved) in advance Example: IP networks,Use Queuing models to Describe the behavior of queuing systems Evaluate system performance,Model: Queuing System,Queuing System,Queue,Server,Customers,Response Time vs. Arrivals,Internet 歷史(1) Sep69 1st IMP in UCLA, Oct69 2nd IMP in SRI Internet 之父- L. Kle

11、inrock1999 1969,History of the Internet (2),History of the Internet (3),Sep69 1st IMP in UCLA Oct69 2nd IMP in SRI 22:30 29Oct69 LOGIN from UCLA to SRI CLA We sent an “L” - did you get the “L”? YEP! We sent a “O” - did you get the “O”? YEP! We sent an “G” - did you get the “G”? Crash!,歷史的網(wǎng)絡(luò)（4）,1961-

12、1972：早期的分組交換原理 1961:讓排隊(duì)理論表明，分組交換的有效性 1964: Baran -軍事網(wǎng)分組交換 1967:阿帕網(wǎng)由高級(jí)研究計(jì)劃局（Licklider，羅伯茨）1969:第一網(wǎng)絡(luò)節(jié)點(diǎn)的操作 1972:網(wǎng)絡(luò)有15個(gè)節(jié)點(diǎn)阿帕網(wǎng)公開(kāi)展示NCP （網(wǎng)絡(luò)控制協(xié)議）第一主機(jī)協(xié)議第一封電子郵件程序,History of the Internet (5),1972-1980: Internetworking, research networks 1970:ALOHAnet satellite network in Hawaii (Abramson) 1973:Metcalfes PhD th

13、esis proposes Ethernet 1974:Cerf and Kahn - 2004 A.M. Turing Award -define todays Internet architecture minimalism, autonomy no internal changes required to interconnect networks best effort service model stateless routers decentralized control 1979:ARPAnet has 200 nodes, 56 kbps Late 70s: proprieta

14、ry architectures: DECnet, SNA Late 70s: switching fixed length packets (- ATM),History of the Internet (6),1980s new protocols, a proliferation of net 1983:deployment of TCP/IP. (Critical separation; Cohen) 1982:SMTP e-mail protocol defined 1983:DNS defined for name-to-IP-address translation mid-198

15、0s: IETF active 1985:FTP protocol defined 1988:TCP congestion control new national networks: Csnet, BITnet, Minitel , NSFnet (1.5 Mbps,10,000 computers), NSI (NASA), ESNet(DOE), DARTnet, TWBNet (DARPA), 100,000 hosts connected to confederation of networks,History of the Internet (7),1990s: commercia

16、lization, the WWW Early 1990s: ARPAnet decommissioned 1991: NSFnet (45 Mbps) - commercial use of NSF (decommissioned, 1995) Late 1990s: multiple private backbones 50 million computers on Internet 100 million+ users backbone links running at 1 Gbps Early 1990s: WWW hypertext Bush 1945, Nelson 1960s H

17、TML, http: Berners-Lee 1994: Mosaic, later Netscape late 1990s: commercialization of the WWW,Internet 提供的服務(wù),Shared access to computing resources telnet (1970s) Shared access to data / files FTP, NFS, AFS (1980s) Communication medium over which people interact email (1980s), on-line chat / messaging

18、(1990s) audio, video (1990s) replacing telephone network? A medium for information dissemination USENET (1980s) WWW (1990s) replacing newspaper, magazine? audio, video (1990s) replacing radio, CD, TV?,Internet Physical Infrastructure,Classification by Coverage,模型, 協(xié)議, 分層,Protocol Architecture,Dont N

19、eed All Layers Everywhere,Protocol Data Unit - PDUs,Network Components (Examples),Fibers,Coaxial Cable,Links,Interfaces,Switches/routers,Ethernet card,Wireless card,Large router,Telephone switch,Growth of the Internet,Today: backbones run at 2.4/10/100 Gbps, 500 millions computers in 150 countries,中

20、科院高能物理所 1993年3月64Kbps 1986.8.25 Email TJU:1995年3月22日 2009年7月 網(wǎng)民 3.4億 WWW站 306萬(wàn) CN域名 1296萬(wàn) 國(guó)際出口帶寬 748 Gbps 連接美國(guó)、俄羅斯、法國(guó)、英國(guó)、德國(guó)、日本、韓國(guó)、新加坡等 寬帶接入速度遠(yuǎn)遠(yuǎn)落后于發(fā)達(dá)國(guó)家,Internet 在中國(guó),趨勢(shì): 網(wǎng)絡(luò)時(shí)代,每一件事務(wù)都是數(shù)字的: 聲音, 視頻, 音樂(lè), 畫(huà)片 每一件事務(wù)都是在線的: 銀行, 醫(yī)療, 航空, 天氣情況, 公路交通, 每個(gè)人之間都是相互聯(lián)系的:醫(yī)生,教師,經(jīng)濟(jì)人,母親,兒子, 朋友, 敵人 實(shí)現(xiàn)家庭 教育， 辦公， 購(gòu)物， 娛樂(lè)/網(wǎng)上娛樂(lè) 虛擬

21、工作場(chǎng)所 2000年，美國(guó)有五千五百萬(wàn)人實(shí)現(xiàn)遠(yuǎn)程工作 網(wǎng)絡(luò)制造/電子商務(wù),趨勢(shì): 網(wǎng)絡(luò)時(shí)代,計(jì)算機(jī)集成制造系統(tǒng)/先進(jìn)制造/信息化CIMS (Computer Integrated Manufacturing),1973 Dr. Joseph Harrington 目標(biāo)：市場(chǎng)競(jìng)爭(zhēng) - T, Q, C, S 時(shí)間T（即開(kāi)發(fā)新產(chǎn)品的時(shí)間或成熟產(chǎn)品的上市時(shí)間）、質(zhì)量Q、成本C和服務(wù)S 核心思想 系統(tǒng)的觀點(diǎn) - 全局優(yōu)化 企業(yè)的各個(gè)環(huán)節(jié)，包括市場(chǎng)分析、產(chǎn)品設(shè)計(jì)、加工制造、經(jīng)營(yíng)管理及售后服務(wù)的全部經(jīng)營(yíng)活動(dòng)，是不可以分割的整體. 信息的觀點(diǎn) - 信息集成 企業(yè)的運(yùn)行是信息采集，傳遞，加工處理的過(guò)程. 產(chǎn)品可

22、以看作數(shù)據(jù)的物質(zhì)表現(xiàn).,目標(biāo)-提高競(jìng)爭(zhēng)力（CIMS-Internet）,70年代前,降低勞動(dòng)成本,降低產(chǎn)品成本,70年代,提高企業(yè)整體效益,降低產(chǎn)品成本,提出CIMS,80年代,TQCS,CIMS推廣應(yīng)用,90年代,新產(chǎn)品開(kāi)發(fā)，信息、知識(shí),CIMS發(fā)展,2000年代,核心：服務(wù)/用戶,范圍：全球企業(yè)間/供應(yīng)鏈,資源：信息、知識(shí)（無(wú)時(shí)空）,網(wǎng)絡(luò)制造/ 電子商務(wù),網(wǎng)絡(luò)制造,Internet從單純的信息工具變成”E時(shí)代”的關(guān)鍵資源.全球經(jīng)濟(jì)一體化成為制造業(yè)變革的最根本的推動(dòng)力 基于Internet的虛擬制造與虛擬裝配 在相互聯(lián)結(jié)的網(wǎng)絡(luò)上，建立24小時(shí)工作的協(xié)同工作組，大大加快了設(shè)計(jì)進(jìn)度、及時(shí)獲得所需

23、要的零部件，減少庫(kù)存、降低成本，提高質(zhì)量 網(wǎng)絡(luò)制造的本質(zhì)特性就是產(chǎn)品的制造過(guò)程更加分散化，信息的傳遞網(wǎng)絡(luò)化，信息的流動(dòng)伴隨著各項(xiàng)工作的并發(fā)進(jìn)行而同時(shí)發(fā)生,電子商務(wù),信息技術(shù)和Internet引發(fā)的商務(wù)過(guò)程的變化 利用以Internet為核心的信息技術(shù)，進(jìn)行商務(wù)活動(dòng)和企業(yè)資源管理 CIMS是企業(yè)實(shí)施電子商務(wù)的基礎(chǔ) 企業(yè)實(shí)施電子商務(wù)是CIMS發(fā)展的主要標(biāo)志和主要內(nèi)容,競(jìng)爭(zhēng)環(huán)境改變,核心 產(chǎn)品競(jìng)爭(zhēng),電子商務(wù)產(chǎn)生背景,服務(wù)競(jìng)爭(zhēng),范圍 單個(gè)企業(yè),全球多企業(yè),資源 人、財(cái)、物,信息、知識(shí),管理重心遷移,生產(chǎn)管理,供應(yīng)/營(yíng)銷鏈管理,集中內(nèi)部資源,整合外部資源,離散管理,集約管理,商務(wù)模式轉(zhuǎn)化,文秘型管理 關(guān)

24、注后臺(tái)（企業(yè)內(nèi)部） 關(guān)注業(yè)務(wù)記錄（報(bào)表） 地區(qū)性 推銷產(chǎn)品為中心 （賣方市場(chǎng)）,自我服務(wù)型管理 關(guān)注前端（客戶關(guān)系） 要求商業(yè)智能（分析） 全球化 客戶為中心 （買方市場(chǎng)）,傳統(tǒng)商務(wù),電子商務(wù),客戶,供應(yīng)商,合作伙伴,網(wǎng)絡(luò)智能,市場(chǎng)營(yíng)銷,產(chǎn)品/服務(wù) 銷售,產(chǎn)品制造,服務(wù)/支持,e企業(yè)的業(yè)務(wù)體系結(jié)構(gòu),協(xié)同產(chǎn)品商務(wù)( CPC),用戶在互聯(lián)網(wǎng)上參與產(chǎn)品的開(kāi)發(fā)、設(shè)計(jì)及修訂。 在虛擬市場(chǎng)空間中，顧客與生產(chǎn)者及供應(yīng)商一起參與產(chǎn)品生命周期中的每一項(xiàng)技術(shù)及商業(yè)環(huán)節(jié)。 不受地域及時(shí)間的限制，信息可以快速地流動(dòng)。,企業(yè)的發(fā)展趨勢(shì),部門之間的障礙,業(yè)務(wù)過(guò) 程重組 IDS Sheer,業(yè)務(wù)流程,2000年以后,電子商

25、務(wù)工程 IDS Sheer,企業(yè)之間的障礙,網(wǎng)絡(luò)制造-電子商務(wù),網(wǎng)絡(luò)發(fā)展趨勢(shì),趨勢(shì): 融合 趨勢(shì): 泛在（Ubiquitous） 趨勢(shì): 信息爆炸 更多的網(wǎng)絡(luò)業(yè)務(wù)流量 數(shù)據(jù)流量 話聲流量 更快的傳輸介質(zhì)/骨干網(wǎng)（Backbone） 更大的帶寬（Bandwidth） 寬帶無(wú)線網(wǎng)飛速增長(zhǎng)(WLAN) (Wi-Fi) Everything over IP,趨勢(shì): 融合,新聞/廣告-媒體-信息提供者 數(shù)字媒體產(chǎn)品 有線電視 視頻傳輸 電話 聲音傳輸 計(jì)算機(jī) 數(shù)字媒體存儲(chǔ)/處理 信息提供者和信息傳輸者的結(jié)合 電話公司, 有線公司, 娛樂(lè)事業(yè), 和計(jì)算機(jī)公司的結(jié)合,Trend:,趨勢(shì): 更快的傳輸介質(zhì),局

26、域網(wǎng)：1 Gbps over 4-pair UTP-5 up to 100 m, 10Gbps being discussed Was 1 Mbps (1Base-5) in 1984 骨干網(wǎng)：光纖DWDM ( Dense Wavelength Division Multiplexing) OC-768 = 40 Gbps over a to 65 km, 1600 Gbps - 10 Tbps Was 100 Mbps (FDDI) in 1993 無(wú)線網(wǎng)：54 /500 Mbps(100-2km-50km) wireless networks, 2.5 Gbps to 5km using

27、light Was 1 Mbps (IEEE 802.11) in 1998,Why Optical Networks? DWDM optoelectricl metro network,Trend:寬帶無(wú)線網(wǎng)飛速增長(zhǎng),Trend:寬帶無(wú)線網(wǎng)(Wi-Fi)飛速增長(zhǎng),Trend: Wireless / Mobile,Integration of 3G and WLAN- offer possibility of achieving anywhere, anytime, high speed and low expense Internet access,Future Internet Resea

28、rch and Experimentation,Todays Internet,Millions of users Web, email, low-quality audio ratio between peek and average rate is 3:1 for audio, and 15:1 for data traffic However, packet-switching needs to deal with congestion: More complex routers Harder to provide good network services (e.g., delay a

29、nd bandwidth guarantees) In practice they are combined: IP over SONET, IP over Frame Relay,Virtual-Circuit Packet Switching,Hybrid of circuit switching and packet switching Data is transmitted as packets All packets from one packet stream are sent along a pre-established path ( = virtual circuit) Gu

30、arantees in-sequence delivery of packets However: Packets from different virtual circuits may be interleaved Example: ATM networks MPLS?,Virtual-Circuit Packet Switching,Router A,Router B,Router C,Router D,Router E,1. Connection Establishment,2. Information Transfer,3. Circuit Disconnect,Virtual Cir

31、cuit Packet Switching-Example,Router F,Timing of Virtual-Circuit Packet Switching,Host 1,Host 2,Node 1,Node 2,propagation delay between Host 1 and Node 1,VC establishment,VC termination,Data transfer,Asynchronous Transfer Mode: ATM,1990s/00 standard for high-speed (155Mbps to 622 Mbps and higher) Br

32、oadband Integrated Service Digital Network architecture Goal: integrated, end-end transport of carry voice, video, data meeting timing/QoS requirements of voice, video (versus Internet best-effort model) “next generation” telephony: technical roots in telephone world packet-switching (fixed length p

33、ackets, called “cells”) using virtual circuits,ATM reference model,How far along are we?,Standardization bodies - ATM Forum, ITU-T We may never see end-to-end ATM (1997) ATM - too complex - too expansive Backbone: - 1995 vBNS (ATM) - 1998 Abilene (SONET) - 2000 IP over DWDM Internet technology + ATM

34、 philosophy but ATM ideas continue to powerfully influence design of next-generation Internet ex: MPLS, admission ctl., resource reservation, .,Best of Both Worlds,Multiprotocol label switching (MPLS) MPLS + IP form a middle ground that combines the best of IP and the best of virtual circuit switchi

35、ng technologies ATM and Frame Relay cannot easily come to the middle so IP has!,Label Encapsulation,MPLS Encapsulation is specified over various media types. Top labels may use existing format, lower label(s) use a new “shim” label format.,Label Substitution,Have a friend go to B ahead of you using

36、one of the previous two techniques. At every road they reserve a lane just for you. At every intersection they post a big sign that says for a given lane which way to turn and what new lane to take.,We are at an Impasse,ISPs are unlikely candidates for architectural change We cant test new architect

37、ures - Despite sizable investments in testbeds We cant deploy new architectures - And things are getting worse, not better Yet there are pressing requirements for which the current architecture is not well suited,GENI (Global Environment for Network Innovations) - NSF 2005 (1),What is GENI? GENI is

38、a facility concept being explored by the US computing community back to an NSF workshop in 2005 focus on architectural research, and provide the experimental infrastructure needed to support that research focus on the research agenda (and infrastructure needs) of the optical, wireless, sensor network, and distributed systems communities,GENI (Global Environment for Network Innovations) (2),The goal of GENI Goal: a Future Internet that meets the demands of 21st century to increase the quality and quantity of experimental research outcomes in networking and distributed s