2001研-第一讲

11 12 13 OSI14 15 16 Internet

11

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11 20Internert20 21

11 1 ,(

11 1 1989-1993 EL-The Mercury roject NIIDL 1994-1998Digital Library Initiative DL 1995, American Memory1990-1995 19966000500 =104TB 1998DL

11 2G8, 3 19936204 830DL 3TB 5 4200288010006 CICOCLC12 IBM DL

11 2 170819991.9620035.02

11 Internet web

11 1 2 34bitbps

11 5 (Information) I=log21/P I P =

11 6(Signal)/

11 78()

11 9 101924(Nyquist) =2Blog2V(bps) BV 01V=2=2B (bps)3000Hz6000bps3000Hz14000bpsVV

11 11Shannon C=Blog2(1+S/N) B/s C(B SNS/N

11 1RC 2CBS/N 3n0N=n0BBC=lim[Blog21+S/n0B]1.44S/n0Sn0 BCC 4C=I/TI=TBlog21+S/N ITBT 10 log10S/N(dB) 10dBS/N1020dBS/N10030dBS/N1000

11 12 8(a) (b)

11 13 4KHz4K (Baseband) (Broadband) ()

11 1000-2000Hz

EMBED Word.Document.8 \s

EMBED Word.Document.8 \s

_1001114643.doc

_1001114656.doc

Modem

B

Modem

A

EMBED PBrush

EMBED PBrush

EMBED PBrush

11 1A/D----D/A--

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11 212 345

12 125075 3 >10Gbps)

12 1 502 35786>=3,120 20--302000MHz

13 OSI

13 OSI OSI/RM(1) (2) (3)

13 OSI(4) (5) (6) (7) OSI

14 (1) (LAN) Mbps--100Mbps(MAN) 1M bps 100M(WAN) bpsM bps

14 (2) EthernetTokenRingX.25X.25TCP/IPTCP/IP

14 (3) NovellNetWare NTWindows NT UNIXUNIX (4) (public network)(private network)

14 (5)

14

1

2

3

4

5

14 123456

14 1/(CSMA/CD)CSMA/CD(Carrier Sense Multiple Access / Collision Detect)CSMA/CDCSMA/CD

14 1OSI (1) (repeater) (2) (bridge) (3) (router) (4) (gateway)()

14 2 ISOOSITCP/IPIP(Internet Protocol)IP

14 1Ethernet 10BASE-510Mbps500 2Ethernet 10BASE-210Mbps200 T

14 3Ethernet 10BASE-T10--100Mbps 3541RJ-452AUIBNC 35

14 1FDDI 2ATMcell53BytesATM 3/

15 1 2ChinaPACChinaDDNChinaFRN 34

15 1ChinaGBN19933 ATMB-ISDN2ChinaNet1995ChinaPACChinaDDN

15 3CERNET1994 8

15 4CSTNET 86Internet 90ChinaPACInternet 93 93NCFC94Internet CASNETCSTNET

15 1 2EDI3POS4ISDNB-ISDN

16 Internet 1 InternetInternet -- InternetARPANET(ARPA)Internet150InternetInternetInternet

16 Internet 2Internet(1) (E-mail) (2) (Telnet)) Internet

16 Internet 2(3) (FTP)FTPInternet(4) Internet(Archie)(Gopher)(WAIS)(WWW)(5) (USENET)(6)

16 Internet 3 TCP/IPInternetTCP/IPTCP(Transmission Control Protocol)IP(Internet Protocol)TCP/IPTCP/IP(1) TCP/IP()

16 Internet 4

16 Internet 5 TCP/IP DNS(Domain Name System)IPFTP(File Transfer Protocol)TELNET(Telecommunication network)SMTP(Simple Mail Transfer Protocol)TFTP(Trivial File Transfer Protocol) TCP(Transmission Control Protocol)UDP(User Data-gram Protocol)

16 Internet 5 IP(Internet Protocol)ICMP(Internet Control Message Protocol)IPARP(Address Resolution Protocol)IPRARP(Reverse ARP)IP;

16 Internet 6IP 1 IP InternetTCP/IPInternetIP 1IP IP(IP)IPIP

16 Internet 6 Internet32(IP)IPDDNNICIP(net-id)(host-id)net-idhost-idIP 5ABCDEABC

16 Internet 7 IP

10 net-id host-id

012 8 16 24 31

110 net-id host-id

0 net-id host-id

C

A

B

16 Internet 82IP 32IP8 IP 11000000 00000000 00000001 00000001192.0.1.1 IPIP A B C(Xnet-id, Yhost-id) X1.Y2.Y3.Y4 X1.X2.Y3.Y4 X1.X2.X3.Y4 126 16384 2097152 16777214 65534 254IP 1.0.0.1 128.1.0.1 192.0.1.1IP 1.0.0.254 128.1.0.254 192.0.1.254IP 126.255.255.1 191.254.255.1 223.255.254.IP 126.255.255.254 191.254.255.254 23.255.254.254

16 Internet2(DNS) InternetDNS()IP Internet(DNSDomain Name System)()InternetDNSIPIPDNS() ..

16 Internet ()Internet() uestc.edu.cn (..)panda.uestc.edu.cnpandapanda()

16 Internet

root domain

com

edu

net

au

cn

edu

uestc

16 InternetInternet()com ru be in edu es fl il gov ch de jp mil gb ie no net at it se org ca nl cn int dk hk()tw ()au fr

16 InternetInternet1 ()host(X.25DDNFRM)InternetIP16Kbit/s2Mbit/sInternet

16 Internet2 ()(MODEM)MODEMISP300bps14.4Kbps(33.6Kbps56Kbps)(Shell Acount)(PPP/SLIP)Internet

16 Internet(1) Shell Acount ISP(ISP)ISPISPISPInternetInternetIPE-mailInternetInternet

16 Internet(2) (PPP/SLIP) ISPPPP/SLIP(ISP)PPP/SLIPTCP/IPMODEMISP(ISPInternet)PPP/SLIPISPInternetInternet

16 InternetPPP/SLIPInternetIPTCP/IPIPPPP(Point to Point Protocol)SLIP(Series Line Internet Protocol) ISPPPP/SLIPPPPSLIPPPP

16 InternetWWW 1WWW WWWInternetWeb()WWW()WWW Web WebWeb Web 3D Web Web

16 Internet () WebWWW WWW(Page)InternetWebWeb

16 Internet(Hyperlink)WWWInternetWeb5.4.1WWW HomePageWWWWeb Web Web (URL)http://www.pku.edu.cn/

16 Internet WEB

16 Internet2(HTML) (HTMLHyper Text Markup Language)WWW3(HTTP) (HTTPHyper Text Transfer Protocol)WebWWW(Client)Web(Server)HTTPHTTPWebWebHTTP

16 Internet4(URL) (URLUniversal Resource Locator)WWWHTMLURLHyperlink()URL()URLURLWWWURL Internet URL Internet gopherHTTP

16 Internet URL :/// URL http://www.computerworld.co.cn/http://www.microsoft.com/backofficehttp:// www.microsoft.com/catalog/oders.htmftp://ftp.netscape.com/ftp://orion.bureau.gov/stars/alpha/starlist.txt http ftp news telnet gophor wais IPIP

16 Internet5Web Web Web Web Web TCP/IP Internet HTTPFTP gopher Web NetscapeNetscape Navigator() MicrosoftInternet Explorer() Web HTML WebWeb/WebWebWebWebURLWebWeb(HTML)Web Web (HTML)HTML

16 InternetHTMLWeb1HTMLHTML(HyperText Markup Language)WWWHTMLHTMLURLInternetWebInternet

16 Internet2HTML(1) HTMLHTMLHTML()()

16 Internet NAME/NAMENAMENAME/NAMENAME()NAME/NAMENAME h1/h1h15.4.2Hnimgsrc:img img src = filename.gif src, (filename.gif,)br

16 Internet(2) HTML

16 Internet(3) HTML HTMLHTML

..HTML ... ...

(4) HTMLHTMLASCIIDOSHTML.HTMWindows 95Windows NTUNIX.HTML

16 Internet3Web HTMLWebHTML

Internet

Internet

Web Internet Web Web

Internet

16 Internet Web

MSN Web

Microsoft Web

Internet Web

HTMLWeb5.4.24Web5.4.25WebMicrosoft Web5.4.26Web

16 Internet1 1999714CNNICInternet99.71999630146400241M CNNIC) http://www.sina.com.cn ) http://www.sohu.com ( http://www.sohoo.com.cn ) )263: http://www.263.net

16 Internet) http://www.yahoo.com)http://www.nease.net (netease.com, 163.com ) )163: http://www.163.net ): http://gbchinese.yahoo.com ): http://www.cpcw.com ): http://www.online.sh.cn )21cn: http://www.21cn.com )chinabyte: http://www.chinabyte.com ): http://www.cctv.com http://www.cnnic.net.cn19

16 Internet2 (1) YAHOO http://www.yahoo.com/ YAHOOInternet (2) ALTAVISTA http://www.altavista.digital.com/ ALTAVISTA 199512ALTAVISTAALTAVISTA

16 Internet(3) LYCOS http://www.lycos.com/ LYCOS (4) http://www.searchenginewatch.com/

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2001研-第一讲