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1 ICMP 0466-XX (ipv4) 2001:200:0:8803::53 (ipv6) (FQDN: Fully Qualified Domain Name) ( /MAC ID 00:11:24:79:8e:82 Port Port = = Port v63ffe:501:100c:d210:2a0:24ff:fe29:314d v v6128bitv432bit () 1

2 : 2001:200:0:8803::53/64 (64bit) : 200 : 0 : 8803 : 0 : 0 : 0 : 53 = 2001:200:0:8803::/64 (64bit) 2001:200:0:880 3::53/ :200:0:880 3::1/ :200:0:880 3::100/64 ABCARP BCA A D E 203. Address Netmask 0xffffffe N1 B C DEBCN1 Prefix Length /27 Address & Netmask Network (bit) Subnet /27 R N R N A B C D E N N1 N / /16 2

3 Network Address Translation,LAN Internet global network Router xdsl private network XXX 20 (ex /24) 21 (ex /24) # /8 ( ) ARP A A ARP Address Resolution Protocol IEEE802.3(Ethernet), 802.5(token ring), (Wireless) ARP 32bit ARP RARP 48bit MAC ARP ARP Ethernet driver A Ethernet driver ARP ARP Ethernet Broadcast ARP Ethernet driver A A 3

ARP(PC UNIX) ping ARP ARP(Windows) MAC Routing Table Lookup A Dst NH I/F B B N1 C B N1 D B N1 N1 Routing Table Lookup Dst NH I/F A A N1 C C N2 D D N3 B AD N3 N2 C D () interface interface interface

4 ARP(PC UNIX) ping ARP ARP(Windows) MAC Routing Table Lookup A Dst NH I/F B B N1 C B N1 D B N1 N1 Routing Table Lookup Dst NH I/F A A N1 C C N2 D D N3 B AD N3 N2 C D () interface interface interface interface PtoP ID Ethernet I/F / IF-a /8 --- IF-b / IF-b IF-a IF-b R I/F / IF-b /8 --- IF-a / IF-a IF-a IF-b R N1 N2 N / / /24 4

5 netstat -rn %netstat -rn Routing tables Internet: Destination Gateway Flags Refs Use Netif Expire default UGSc vx UH 0 56 lo link#1 UC 0 0 de0 => /25 link#2 UC 0 0 vx0 => Destination: Gateway : Netif : Expire :routing table next hop default Ether = Enet = Ether next hop next hop = Enet = match /17 match /20 match / / / N1 (Route aggregation) EN1N2 D A D E N / (Route aggregation) / IF-a / IF-a / IF-a / / I/F / Class A/B/C/D VLSM/CIDR Variable Length Subnet Mask Classless Inter Domain Routing Rv1/IGRP Classfull v6 5

6 Mobility!=?! Mobility : A A B B C C 1 () () 16bit(65536) Wellknown(11023) ftp 21 telnet 23 dns 53 http 80 6

7 7 Ethernet Ethernet

8 8 Ethernet Internet Control Message Protocol +

9 ICMP: Network Unreachable ICMP: Port Unreachable Host B Router!! Host B Host A Header 20byte ICMP Router ICMP message Router Host B Host A Header 20byte ICMP Router ICMP message Host B traceroute traceroute(1) Van Jacobson UDP TTL1 TTL=0ICMP time exceed 1 TTL=1 ICMP Time Exceed traceroute(2) traceroute(3) TTL1 TTL TTL02ICMP Time Exceed 2 ICMP Port Unreachable TTL=1 TTL=2 TTL=1 TTL=4 TTL=3 TTL=2 ICMP Time Exceed ICMP Port Unreachable 9

10 traceroute n windowstracert -d gen@kneuklid% tracert Tracing route to [ ] over a maximum of 30 hops: 1 * * * Request timed out. 2 <1 ms <1 ms <1 ms cisco11.fujisawa.wide.ad.jp [ ] 3 2 ms 1 ms 1 ms foundry2.otemachi.wide.ad.jp [ ] 4 2 ms 2 ms 2 ms as6461.nspixp2.wide.ad.jp [ ] 5 2 ms 8 ms 3 ms so cr2.nrt3.jp.mfnx.net [ ] ms 113 ms 114 ms so cr1.sjc3.us.mfnx.net [ ] ms 105 ms 105 ms pos9-1.mpr1.pao1.us.mfnx.net [ ] ms 104 ms 103 ms pos9-0.mpr2.pao1.us.mfnx.net [ ] ms 119 ms 119 ms bpr1-so paloaltopaix.cw.net [ ] ms 119 ms 122 ms agr1-loopback.santaclara.cw.net [ ] ms 119 ms 119 ms dcr1-so santaclara.cw.net [ ] ms 120 ms 120 ms cable-and-wireless-internal-isp.santaclara.cw.net [ ] ms 117 ms 117 ms bbr02-g6-0.sntc05.exodus.net [ ] ms 118 ms 118 ms bbr01-p7-0.sntc03.exodus.net [ ] ms 117 ms 117 ms dcr04-g1-2.sntc03.exodus.net [ ] ms 121 ms 121 ms csr01-ve240.sntc03.exodus.net [ ] ms 107 ms 107 ms google-exodus.exodus.net [ ] ms 105 ms 105 ms exbi2-1-1.net.google.com [ ] ms 106 ms 106 ms [ ] Trace complete. traceroute TTL ( ) (/)UDP () + / 10

11 OSI Web /UDP / LAN IM xdsl/ () 16bit(65536) (FAX) FAX FAX( ) UDP/ UDP(User Datagram Protocol) CL (Connectionless) (Transmission Control Protocol) CO (Connection Oriented) Virtual Circuit 11

12 UDP ftp client #2048 transport layer ftp service #21 UDP dns service #53 #23 telnet service UDP Ethernet network layer physical layer Ethernet UDP UDP ICMP Port Unreachable UDP NFS, T, SNMP DNS, / / RTP Real-time Transport Protocol UDP,etc. RTP/UDP Vo DVTS 12

13 5(1024 Internet Explorer, 80, TracerouteTTL 12 state diagram 3Way Handshake SYN SYN + ACK PiggyBack ACK 13

14 FIN FIN FIN + ACK FIN + ACK FIN FIN + ACK FIN ACK FIN + ACK MSL(TIME_WAIT) CLOSING FIN CLOSING FIN FIN + ACK FIN + ACK CLOSING FIN+ACK FIN MSL TTL 3012 RST RST *) UDPICMP Port Unreachable ACK ACK 14

15 PiggyBack ACK ACK SYN SYN PiggyBack Data+ACK FIN+ACK SYN SYN+ACK ACK () () 15

16 ACK ACK MSS1/2 MSS1/2 16

17 RTT Network Packet loss Back-off 64sec 1byte Back-off 5>, 6, 12, 24, 48, 60, 60, 60 (sec) 2 2set 75sec10 RST telnet, rlogin, ssh http, Vo ftp, scp SYNFIN UDP : hostahost B permit hostb to hosta deny all to hosta hostassh permit all to hostb port=22 deny all to hostb 17

18 : : 1: http 2: QoS: Quality of Service Address, Port MPLS Cut through QoS Routing 18

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untitled ()IP OSI ( ) (TCP/IP)TCP UDP ( ) IP + IP TCP / Web TCP/UDP IP / LAN IM xdsl/ () (FAX) 6bit(6556) FAX FAX ( ) UDP/TCP UDP(User Datagram Protocol) CL (Connectionless) TCP(Transmission Control Protocol) CO