r4.dvi

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1 :? PC LAN Web?? ( ) [4] [5] my PC [2] congested service [1]? [3] 1: LAN LAN ( )[1] LAN ( ) PC ( )[2] Web ( )[3] ping ( ) ( )[4] SSL ( ) ( / / )[5] 1

2 1.2 (multiple layered-structure) ( ) (physical layer) [1] A B (0/1 ) 0 1 (datalink layer) [2] ( A B ) (network layer) [3] (transport layer) [4] (sesseion layer) (persentation layer) (application layer) [5] 7 ISO( ) (OSI Open System Interconnect) OSI 7 ( 2) Application Application a) Presentation Presentation Session Session b) Transport Transport c) Network Network Network Network d) Data Link Data Link Data Link Data Link X Y e) Physical Physical Physical Physical 2: OSI ( ) ( ) 3 2

3 (protocol) 0/1 ( ) ( ) ( ) ( ) (interface) 1.3 (packet switching) 1 (packet) 1 ( ) ( 3) A B C D E F AtoF BtoE AtoF AtoF BtoE BtoE 3: ( ) ( ) 1 (best effort)? 4-1 ( ) ( ) (2 1?) a c 1 4 ( ) 3

4 a c ( ) 1 a. 10 b. 10 c. ( )? ( 4) ( ) OK 2 OK 4 OK : 2 TCP/IP 2.1 TCP/IP ( ) TCP IP 2 TCP/IP TCP/IP IPv4 IPv6 IPv4 TCP/IP 5 IP(Internet Protocol) ( ) IP IP 1 : (ACK) ACK 4

5 rwho tftp wall telnet ftp smtp nntp rlogin rcp rexec nis NFS Application Presentation Session UDP TCP Transport Internet Protocol (IP) Network loopback Ethernet Driver PPP Data Link Ethernet Serial/ADSL Physical 5: TCP/IP IP UDP (User Datagram Protocol) TCP (Transmission Control Protocol) UDP TCP TCP/IP UDP TCP 2.2 (1 2 ) TCP/IP ( ) C C C C C C C C C C C C yellow cable Hub Switch 6: Ethernet (Ethernet) LAN ( ) ( 6 ) (UTP Unshielded Twisted-Pair cable) (hub) ( 6 ) (switching hub) UTP 100Mbps 10Gbps 100m / LAN 5

6 WPA(Wi-Fi Protected Access) WPA2(Wi-Fi Protected Access 2) WPS(Wi-Fi Protected Setup) ( LAN ) 2 (UDP ) /* recv.c -- packet receiving example. */ #include <stdlib.h> #include <stdio.h> #include <unistd.h> #include <sys/socket.h> #include <netinet/in.h> 3 int main(int argc, char *argv[]) { int fd, len; char buf[100]; socklen_t fromlen; static struct sockaddr_in adr; struct sockaddr *p = (struct sockaddr*)&adr; adr.sin_family = AF_INET; adr.sin_addr.s_addr = INADDR_ANY; adr.sin_port = htons(atoi(argv[1])); if((fd = socket(pf_inet, SOCK_DGRAM, IPPROTO_UDP)) < 0 bind(fd, p, sizeof(adr)) < 0) { perror("socket"); exit(1); } while(1) { len = recvfrom(fd, buf, 100, 0, 0, &fromlen); if(len < 0) { perror("recv"); exit(1); } write(1, buf, len); } } #include... main fd ( ) len fromlen buf adr fd bind ( ) OS ( ) recvfrom OS recvfrom buf recvfrom write IP ifconfig 4 2 LAN WEP(Wireless Encription Privacy) 3 send/recv 4 GSSM /sbin/ifconfig MacOS X ifconfig Windows ipconfig 6

7 % /sbin/ifconfig em0: flags=8843<up,broadcast,running,simplex,multicast> mtu 1500 options=3<rxcsum,txcsum> inet netmask 0xff broadcast ether 00:0f:ea:10:4c:71 media: Ethernet autoselect (1000baseTX <full-duplex>) status: active lo0: flags=8049<up,loopback,running,multicast> mtu inet netmask 0xff em0 ( ) inet(ip IP IP ( ) % cc -o recv recv.c %./recv ( ) /* send.c -- packet sending example. */ #include <stdlib.h> #include <stdio.h> #include <unistd.h> #include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> int main(int argc, char *argv[]) { int fd, len; char buf[20]; struct sockaddr_in adr; struct sockaddr *p = (struct sockaddr*)&adr; adr.sin_family = AF_INET; adr.sin_addr.s_addr = INADDR_ANY; if((fd = socket(pf_inet, SOCK_DGRAM, IPPROTO_UDP)) < 0 bind(fd, p, sizeof(adr)) < 0) { perror("socket"); exit(1); } adr.sin_port = htons(atoi(argv[1])); adr.sin_addr.s_addr = inet_addr(argv[2]); while((len = read(0, buf, 20)) > 0) { if(sendto(fd, buf, len, 0, p, sizeof(adr)) < 0) {perror("send");exit(1);} } } sendto IP 7

8 % cc -o send send.c recv % send IP hello. this is a pen.... recv ( Ctrl-C ) send % less t aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb ccccccccccccccccccccccccccccccccccccccccccccccccccccccccc ddddddddddddddddddddddddddddddddddddddddddddddddddddddddd aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb... % cat t t t t send recv ( ) aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb ccccccccccccccccccccccccccccccccccccccccccccccccccccccccc ddddddddddddddddddddddddddddddddddddddddddddddddddddddddd... aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb bbbbbbbbbbbbbbbbbbb?...??? ( 4096 ) 4-2 send/recv 5 1 a. ( IP ) b. 5 GSSM Windows/Mac OS X Web ( ) 8

9 c IP IP TCP/IP IP IP IP TCP/IP 1980 IPv ( 7 ) IP address network part host part netmask : IP 32 IP (network part) (host part) 1 LAN (netmask) ( 7 ) 8 IP (global IP address) IP ( ) IP 1 ( ) IP ICANN 9 JPNIC 10 ( ) 6 : recv.c send.c ( 32 ) (16 ) 9 Internet Corporation for Assigned Names and Numbers 10 JaPan Network Information Center 9

10 IP IP (private address) GSSM 10.*.*.* utogw IP 11 GSSM Web Web utogw NAT (Network Address Translation) LAN NAT ( ) IPv6 IP IP? 8 C GSSM (switch) (hub) 1 LAN LAN LAN 1 ( ) TCP/IP (router) LAN ISP (Internet Service Provider) ISP WAN ( ) A B WAN 13 A B 11 utogw GSSM IPv6 13 ISP IX (Internet exchange) 10

11 C C C C LAN WAN IX WAN WAN WAN 8: ISP(NTT KDD ) ISP NTT KDD ( ) 1 (RTT Round-Trip Time) RTT? ( ) Web URL Royalty Hotel // ( ) RTT ping 15 % /sbin/ping royaltyhotel.com.br PING royaltyhotel.com.br ( ): 56 data bytes 14 Web 15 GSSM utogw rlogin /sbin/ping ping 14 11

12 64 bytes from : icmp_seq=0 ttl=109 time= ms 64 bytes from : icmp_seq=1 ttl=109 time= ms 64 bytes from : icmp_seq=2 ttl=109 time= ms ^C Ctrl-C % RTT 280msec 140msec 4-3 Royalty Hotel 1 ( ) a. ( ) b. 16 c. 2.5 (3 ) IP TCP/IP IP IP (routing) IP? IP (LAN ) ( N ) (routing table) 9 4 N1 N5 16 traceroute 17 1 (aggregation) 17 12

13 N1:* 1 N2:* 2 B N3:* 3 C N4:* 3 C N5:* 3 C N1:* 1 A N2:* 2 N3:* 3 C N4:* 3 C N5:* 3 C N1 1 2 A B N2 N5 h1 2 D C N3 N4 N1:* 1 N2:* 1 N3:* 1 N4:* 3 N5:* 3 C C C N1:* 4 N2:* 1 N3:* 3 A B N4:* 3 D N5:* 3 D 9: A N5:h1 3 C C 3 D D N5 ping RTT traceroute ( ) 18 % traceroute royaltyhotel.com.br traceroute to royaltyhotel.com.br ( ), 64 hops max, 40 byte packets 1 plalagw ( ) ms ms ms ( ) ms ms ms ( ) ms ms ms ( ) ms ms ms 5 i s99.a049.ap.plala.or.jp ( ) ms ms ms 6 i s99.a049.ap.plala.or.jp ( ) ms i s99.a049.ap.plala.or.jp ( ) ms ms ( ) ms ms ms ( ) ms ms ( ) ms ( ) ms ms ms 10 ae-5.r21.tokyjp01.jp.bb.gin.ntt.net ( ) ms ms ms 11 as-2.r21.snjsca04.us.bb.gin.ntt.net ( ) ms ms ms 12 ae-2.r06.snjsca04.us.bb.gin.ntt.net ( ) ms ms ms 13 te3-3-10g.ar3.sjc2.gblx.net ( ) ms ms te6-4-10g.ar4.lax1.gblx.net ( ) ms ( ) ms ms ms 15 static datacenter1.com.br ( ) ms static datacenter1.com.br ( ) ms static datacenter1.com.br ( ) ms 16 static datacenter1.com.br ( ) ms ms ms 17 static datacenter1.com.br ( ) ms ms ms 18 GSSM traceroute Windows tracert ) 13

14 ( * * * ) GSSM plala (ISP ) 10 plala NTT NTT ( 120 ) Gbl X ( 300 ) traceroute 1 ( ) a. b. b. GSSM ( ) (4 ) UDP TCP TCP/IP TCP UDP 2 UDP IP UDP UDP TCP TCP IP ( ) TCP UDP (port number) (well-konwn ports) TCP UDP ( IANA ) Unix /etc/services TCP UDP netstat -a 19 a b GSSM PC 14

15 % netstat -a Active Internet connections Proto Recv-Q Send-Q Local Address Foreign Address (state) tcp4 0 0 sma.nfsd smp.798 ESTABLISHED tcp4 0 0 sma.nfsd smri ESTABLISHED tcp4 0 0 sma smr04.x11 ESTABLISHED tcp4 0 0 sma.canna smm ESTABLISHED tcp4 0 0 sma.nfsd smr ESTABLISHED tcp4 0 0 sma.canna smri ESTABLISHED tcp4 0 0 sma.nfsd smri ESTABLISHED tcp4 0 0 sma.nfsd smri ESTABLISHED tcp4 0 0 sma.nfsd smr ESTABLISHED tcp4 0 0 sma.nfsd utogw.788 ESTABLISHED tcp4 0 0 localhost.smtp *.* LISTEN udp4 0 0 localhost.ntp *.* udp4 0 0 sma.ntp *.* udp4 0 0 localhost.1019 localhost.1022 % tcp4 udp4 IPv4 TCP UDP. /etc/services TCP ( ) 2.7 / / (5 7 ) OSI 7 3 TCP/IP 2.8 DNS IP IP ( ) (domain name) IP DNS (Domain Name System). ( ) utogw.gssm.otsuka.tsukuba.ac.jp utogw.gssm.otsuka.tsukuba.ac.jp 15

16 DNS (TLD Top-Level Domain) ( ) TLD ( ) 3 IP DNS ( Web ) nslookup % nslookup Server: utogw.gssm.otsuka.tsukuba.ac.jp Address: Non-authoritative answer: Name: Addresses: , , IP 3 IP 3 16

r4.dvi

r4.dvi 11 4 2010.5.11 1 1.1 :???? ( : ) ( 1)? 1:? Google Web www.museuhistoriconacional.com.br ping % /sbin/ping www.museuhistoriconacional.com.br PING museuhistoriconacional.com.br (200.198.87.5): 56 data bytes