Computer Networks v4 cs.sjtu 12/21/12 6 Internet ftp://ftp.cs.sjtu.edu.cn/ybzhang 61 / 110
Computer Networks v4 cs.sjtu 12/21/12 ftp://ftp.cs.sjtu.edu.cn/ybzhang 62 / 110
Computer Networks v4 cs.sjtu 12/21/12 OSI ftp://ftp.cs.sjtu.edu.cn/ybzhang 63 / 110
Computer Networks v4 cs.sjtu 12/21/12! 1 () / TPDU / 2 () Tnbm P482 Fig. 6-1 ftp://ftp.cs.sjtu.edu.cn/ybzhang 64 / 110
Computer Networks v4 cs.sjtu 12/21/12 ftp://ftp.cs.sjtu.edu.cn/ybzhang 65 / 110
Computer Networks v4 cs.sjtu 12/21/12 TCP/IPFTPTelnet TCP/IPSNMPDNS ftp://ftp.cs.sjtu.edu.cn/ybzhang 66 / 110
Computer Networks v4 cs.sjtu 12/21/12 ftp://ftp.cs.sjtu.edu.cn/ybzhang 67 / 110
Computer Networks v4 cs.sjtu 12/21/12! TPDU LISTEN () CONNECT CONNECTION REQ SEND DATA RECEIVE () DATA TPDU DISCONNECT DISCONNECTION REQ ftp://ftp.cs.sjtu.edu.cn/ybzhang 68 / 110
Computer Networks v4 cs.sjtu 12/21/12 Berkeley Sockets SOCKET BIND LISTEN ACCEPT CONNECT SEND RECEIVE CLOSE ftp://ftp.cs.sjtu.edu.cn/ybzhang 69 / 110
Computer Networks v4 cs.sjtu 12/21/12 IP ftp://ftp.cs.sjtu.edu.cn/ybzhang 610 / 110
Computer Networks v4 cs.sjtu 12/21/12 6 Internet ftp://ftp.cs.sjtu.edu.cn/ybzhang 611 / 110
Computer Networks v4 cs.sjtu 12/21/12 ftp://ftp.cs.sjtu.edu.cn/ybzhang 612 / 110
Computer Networks v4 cs.sjtu 12/21/12 ftp://ftp.cs.sjtu.edu.cn/ybzhang 613 / 110
Computer Networks v4 cs.sjtu 12/21/12 TSAP Transport Service Access Point TSAP TCPTCP NSAPNetwork Service Access PointNSAPIPIP ftp://ftp.cs.sjtu.edu.cn/ybzhang 614 / 110
Computer Networks v4 cs.sjtu 12/21/12 TSAP 1208 2 1 1 2 TSAP 1522 TSAP 1836 NSAP NSAP 1 3 4 2 Tnbm P494 Fig. 6-8 TSAPNSAP ftp://ftp.cs.sjtu.edu.cn/ybzhang 615 / 110
Computer Networks v4 cs.sjtu 12/21/12 1. 21522TSAP LISTEN 2. 1 CONNECT1208TSAP 1522TSAP 3. 1 4. 2 5. ftp://ftp.cs.sjtu.edu.cn/ybzhang 616 / 110
Computer Networks v4 cs.sjtu 12/21/12 TSAP well-known TSAP TSAP name server directory server TSAP114 TSAP ftp://ftp.cs.sjtu.edu.cn/ybzhang 617 / 110
Computer Networks v4 cs.sjtu 12/21/12 TSAP initial connection protocol 1 2 1 2 TSAP (a) (b) Tnbm P496 Fig. 6-9 12 ftp://ftp.cs.sjtu.edu.cn/ybzhang 618 / 110
Computer Networks v4 cs.sjtu 12/21/12 1. 2 TCP 2. 1TSAP CONNECT 3. 2 4. 2 ftp://ftp.cs.sjtu.edu.cn/ybzhang 619 / 110
Computer Networks v4 cs.sjtu 12/21/12 ftp://ftp.cs.sjtu.edu.cn/ybzhang 620 / 110
Computer Networks v4 cs.sjtu 12/21/12 ftp://ftp.cs.sjtu.edu.cn/ybzhang 621 / 110
Computer Networks v4 cs.sjtu 12/21/12 TPDU CRACC ftp://ftp.cs.sjtu.edu.cn/ybzhang 622 / 110
Computer Networks v4 cs.sjtu 12/21/12 t 1 2 CR(seq=x) ACC(seq=y,ACK=x) DATA(seq=x,ACK=y) 1x (seq=x)21 y (seq=y,ack=x)1 TPDU 2(seq=x,ACK=y) (a) Tnbm P501 Fig. 6-11 CRConnection Request ACCConnection Accepted ftp://ftp.cs.sjtu.edu.cn/ybzhang 623 / 110
Computer Networks v4 cs.sjtu 12/21/12 TPDU CRACC ftp://ftp.cs.sjtu.edu.cn/ybzhang 624 / 110
Computer Networks v4 cs.sjtu 12/21/12 1 TPDU t 1 CR(seq=x) ACC(seq=y,ACK=x) REJECT(ACK=y) (b)cr 2 Tnbm P501 Fig. 6-11 1 TPDU1 22 1 TPDUTPDU y(seq=y,ack=x)1 21 TPDU ftp://ftp.cs.sjtu.edu.cn/ybzhang 625 / 110
Computer Networks v4 cs.sjtu 12/21/12 TPDU CRACC ftp://ftp.cs.sjtu.edu.cn/ybzhang 626 / 110
Computer Networks v4 cs.sjtu 12/21/12 t 2 CRACC 1 CR(seq=x) ACC(seq=y,ACK=x) DATA (seq=x,ack= z) REJECT(ACK=y) (c)crack 2 Tnbm P501 Fig. 6-11 2 CR 2y 21 2 1 ytpdu TPDU2 2zy TPDU ftp://ftp.cs.sjtu.edu.cn/ybzhang 627 / 110
Computer Networks v4 cs.sjtu 12/21/12 ftp://ftp.cs.sjtu.edu.cn/ybzhang 628 / 110
Computer Networks v4 cs.sjtu 12/21/12 AB BA ftp://ftp.cs.sjtu.edu.cn/ybzhang 629 / 110
Computer Networks v4 cs.sjtu 12/21/12 1 DR CR ACC DATA DATA 2 Tnbm P502 Fig. 6-12 1 TPDU 21 TPDU2 TPDU DISCONNECT ftp://ftp.cs.sjtu.edu.cn/ybzhang 630 / 110
Computer Networks v4 cs.sjtu 12/21/12 AB BA? ftp://ftp.cs.sjtu.edu.cn/ybzhang 631 / 110
Computer Networks v4 cs.sjtu 12/21/12 AB A? B AB ftp://ftp.cs.sjtu.edu.cn/ybzhang 632 / 110
Computer Networks v4 cs.sjtu 12/21/12 TPDU DR ftp://ftp.cs.sjtu.edu.cn/ybzhang 633 / 110
1 1 DR ACK DR DR ACK 2 DR Tnbm P505 Fig. 6-14(a) Computer Networks v4 cs.sjtu 12/21/12 1 DR 21 DR DR1 2 DR ACK2 1 ACK ftp://ftp.cs.sjtu.edu.cn/ybzhang 634 / 110
Computer Networks v4 cs.sjtu 12/21/12 TPDU DR ftp://ftp.cs.sjtu.edu.cn/ybzhang 635 / 110
1 DR ACK ACK DR DR Tnbm P505 Fig. 6-14(b) 2 DR TPDU 2 TPDU Computer Networks v4 cs.sjtu 12/21/12 1 DR 2 1 DR DR 1 2 DR ACK2 1 ACK ftp://ftp.cs.sjtu.edu.cn/ybzhang 636 / 110
Computer Networks v4 cs.sjtu 12/21/12 TPDU DR ftp://ftp.cs.sjtu.edu.cn/ybzhang 637 / 110
Computer Networks v4 cs.sjtu 12/21/12 3 1 1 DR DR ACK DR DR DR ACK 2 DR DR DR 2 1 DR DR 1 2 DR DR Tnbm P505 Fig. 6-14(c) ftp://ftp.cs.sjtu.edu.cn/ybzhang 638 / 110
Computer Networks v4 cs.sjtu 12/21/12 TPDU DR ftp://ftp.cs.sjtu.edu.cn/ybzhang 639 / 110
4 DR Computer Networks v4 cs.sjtu 12/21/12 1 DR DR N DR 2 DR Tnbm P505 Fig. 6-14(d) DR 1 DR 21 DR DR TPDU n ftp://ftp.cs.sjtu.edu.cn/ybzhang 640 / 110
Computer Networks v4 cs.sjtu 12/21/12 ftp://ftp.cs.sjtu.edu.cn/ybzhang 641 / 110
Computer Networks v4 cs.sjtu 12/21/12 PDU ftp://ftp.cs.sjtu.edu.cn/ybzhang 642 / 110
B m2 A ACK Computer Networks v4 cs.sjtu 12/21/12 TPDU A B 1 <8> A8 2 <ack=15,buf=4 > B4 3 <seq=0,data=m0> Am0A3 4 <seq=1,data=m1> Am1A2 5 <seq=2,data=m2> Am2A1 6 <ack=1,buf=3> Bm0,m13 7 <seq=3,data=m3> Am3A1 8 <seq=4,data=m4> Am40 9 <seq=2,data=m2> m2am2a0 10 <ack=4,buf=0> Bm40 11 <ack=4,buf=1> Bm41 12 <ack=4,buf=2> Bm4B2 13 <seq=5,data=m5> Am5A1 14 <seq=6,data=m6> Am60 15 <ack=6,buf=0> Bm60 16 <ack=6,buf=4> Bm64 1 ftp://ftp.cs.sjtu.edu.cn/ybzhang 643 / 110 Tnbm P509 Fig. 6-16
Computer Networks v4 cs.sjtu 12/21/12 ftp://ftp.cs.sjtu.edu.cn/ybzhang 644 / 110
Computer Networks v4 cs.sjtu 12/21/12 ftp://ftp.cs.sjtu.edu.cn/ybzhang 645 / 110
Computer Networks v4 cs.sjtu 12/21/12 ftp://ftp.cs.sjtu.edu.cn/ybzhang 646 / 110
Computer Networks v4 cs.sjtu 12/21/12 ftp://ftp.cs.sjtu.edu.cn/ybzhang 647 / 110
Computer Networks v4 cs.sjtu 12/21/12 TPDU TPDU ftp://ftp.cs.sjtu.edu.cn/ybzhang 648 / 110
Computer Networks v4 cs.sjtu 12/21/12 ftp://ftp.cs.sjtu.edu.cn/ybzhang 649 / 110
Computer Networks v4 cs.sjtu 12/21/12 S1 TPDU S0 TPDU TPDU ftp://ftp.cs.sjtu.edu.cn/ybzhang 650 / 110
Computer Networks v4 cs.sjtu 12/21/12 ftp://ftp.cs.sjtu.edu.cn/ybzhang 651 / 110
Computer Networks v4 cs.sjtu 12/21/12 S0TPDU TPDU S1 TPDU ftp://ftp.cs.sjtu.edu.cn/ybzhang 652 / 110
Computer Networks v4 cs.sjtu 12/21/12 6 Internet ftp://ftp.cs.sjtu.edu.cn/ybzhang 653 / 110
Computer Networks v4 cs.sjtu 12/21/12 Internet TCPUDPInternet UDP (User Datagram Protocol) TCP (Transmission Control Protocol ) ftp://ftp.cs.sjtu.edu.cn/ybzhang 654 / 110
Computer Networks v4 cs.sjtu 12/21/12 UDP (User Datagram Protocol) UDP UDP RPCRemote Procedure Call RTPReal-Time Transport Protocol ftp://ftp.cs.sjtu.edu.cn/ybzhang 655 / 110
Computer Networks v4 cs.sjtu 12/21/12 UDP UDP DNSSNMP UDP ftp://ftp.cs.sjtu.edu.cn/ybzhang 656 / 110
Computer Networks v4 cs.sjtu 12/21/12 UDP UDPIP ftp://ftp.cs.sjtu.edu.cn/ybzhang 657 / 110
Computer Networks v4 cs.sjtu 12/21/12 UDP 0 8 16 31 UDP UDP UDP UDP Tnbm P526 Fig. 6-23 UDP UDPUDP 0 UDPUDP UDP 8 UDP010 ftp://ftp.cs.sjtu.edu.cn/ybzhang 658 / 110
Computer Networks v4 cs.sjtu 12/21/12 UDP UDP UDP IP IP ftp://ftp.cs.sjtu.edu.cn/ybzhang 659 / 110
Computer Networks v4 cs.sjtu 12/21/12 UDP (User Datagram Protocol) UDP UDP RPCRemote Procedure Call RTPReal-Time Transport Protocol ftp://ftp.cs.sjtu.edu.cn/ybzhang 660 / 110
Computer Networks v4 cs.sjtu 12/21/12 RPC - get-ip-address UDPDNS RPC RPCUDP ftp://ftp.cs.sjtu.edu.cn/ybzhang 661 / 110
Computer Networks v4 cs.sjtu 12/21/12 RPC 1. Client stub 2. Client stub 3. OS 4. OS Server stub 5. Client CPU Server CPU Client Server stub stub 1 5 Client Server 2 4 Operating System Operating System 3 Network Tnbm P528 Fig. 6-24 RPC Stub ftp://ftp.cs.sjtu.edu.cn/ybzhang 662 / 110
Computer Networks v4 cs.sjtu 12/21/12 RPC 1. Client stub 2. Client stubmarshal 3. 4. 5. Server stub 6. ftp://ftp.cs.sjtu.edu.cn/ybzhang 663 / 110
Computer Networks v4 cs.sjtu 12/21/12 RPC RPC/ RPC RPC OSIRPC ftp://ftp.cs.sjtu.edu.cn/ybzhang 664 / 110
Computer Networks v4 cs.sjtu 12/21/12 UDP (User Datagram Protocol) UDP UDP RPCRemote Procedure Call RTPReal-Time Transport Protocol ftp://ftp.cs.sjtu.edu.cn/ybzhang 665 / 110
Computer Networks v4 cs.sjtu 12/21/12 RTP UDPRTP RTP RTP RTP UDP IP OS Tnbm P529 Fig. 6-25(a) RTP ftp://ftp.cs.sjtu.edu.cn/ybzhang 666 / 110
RTP Computer Networks v4 cs.sjtu 12/21/12 UDPUDP RTP RTP RTP 8 bit-8 khzpcmgsmmp3 RTP ftp://ftp.cs.sjtu.edu.cn/ybzhang 667 / 110
Computer Networks v4 cs.sjtu 12/21/12 RTP 0 1 2 3 4 7 8 9 15 16 31 Ver. P X CC M Payload type Sequence number Timestamp Synchronization source identifier Contributing source identifiers Tnbm P531 Fig. 6-26 RTP ftp://ftp.cs.sjtu.edu.cn/ybzhang 668 / 110
RTP Computer Networks v4 cs.sjtu 12/21/12 P4 X CC0-15 Mvideo 8 bitmp3 RTP ftp://ftp.cs.sjtu.edu.cn/ybzhang 669 / 110
Computer Networks v4 cs.sjtu 12/21/12 RTPRTCP RTCPRealtime Transport Control Protocol RTCP RTCP RTCP ftp://ftp.cs.sjtu.edu.cn/ybzhang 670 / 110
Computer Networks v4 cs.sjtu 12/21/12 Internet TCPUDPInternet UDP (User Datagram Protocol) TCP (Transmission Control Protocol ) ftp://ftp.cs.sjtu.edu.cn/ybzhang 671 / 110
Computer Networks v4 cs.sjtu 12/21/12 TCP Connection Orientation End to End Communication Complete Reliability IPTCPIP Full Duplex Communication Stream Interface Reliable Connection Startup Graceful Connection Shutdown ftp://ftp.cs.sjtu.edu.cn/ybzhang 672 / 110
Computer Networks v4 cs.sjtu 12/21/12 TCP TCP TCP TCP TCP TCP TCP ftp://ftp.cs.sjtu.edu.cn/ybzhang 673 / 110
Computer Networks v4 cs.sjtu 12/21/12 TCP port TCPTSAP well-known port 1024 socket IP + ftp://ftp.cs.sjtu.edu.cn/ybzhang 674 / 110
Computer Networks v4 cs.sjtu 12/21/12 TCP 21 FTP 23 TELNET 25 SMTP 53 DNS 80 HTTP 110 POP-3 E-mail Tnbm P534 Fig. 6-27 TCP ftp://ftp.cs.sjtu.edu.cn/ybzhang 675 / 110
Computer Networks v4 cs.sjtu 12/21/12 A C 202.120.26.35 user1 port 500 user2 port 501 1 166.1.11.15 connection 1: (202.120.26.35, 500)-(166.1.11.15, 25) 2 port 25 connection 2: (202.120.26.35, 501)-(166.1.11.15, 25) B 202.120.26.37 user3 port 500 3 connection 3: (202.120.26.37, 500)-(166.1.11.15, 25) ftp://ftp.cs.sjtu.edu.cn/ybzhang 676 / 110
Computer Networks v4 cs.sjtu 12/21/12 TCP TCP TCP TCP TCP TCP TCP ftp://ftp.cs.sjtu.edu.cn/ybzhang 677 / 110
Computer Networks v4 cs.sjtu 12/21/12 TCP 0 4 8 16 31 032 Tnbm P537 Fig. 6-29 TCP 32 ftp://ftp.cs.sjtu.edu.cn/ybzhang 678 / 110
Computer Networks v4 cs.sjtu 12/21/12 TCP URG ACK PSH RST SYN FIN URG ACK PSH RST SYN FIN ftp://ftp.cs.sjtu.edu.cn/ybzhang 679 / 110
Computer Networks v4 cs.sjtu 12/21/12 TCP 0 4 8 16 31 IP IP 00000000 = 6 TCP Tnbm P539 Fig. 6-30 TCP ftp://ftp.cs.sjtu.edu.cn/ybzhang 680 / 110
Computer Networks v4 cs.sjtu 12/21/12 MSS 0 65535536 nn<=14 RFC1323 = *2 RFC1106 NAK ftp://ftp.cs.sjtu.edu.cn/ybzhang 681 / 110
Computer Networks v4 cs.sjtu 12/21/12 TCP TCP TCP TCP TCP TCP TCP ftp://ftp.cs.sjtu.edu.cn/ybzhang 682 / 110
TCP TCP Computer Networks v4 cs.sjtu 12/21/12 3-way handshake TCPSYNFIN 1 2 SYN (seq=x) SYN (seq=y, ACK=x+1) x y SYN (seq=x+1, ACK=y+1) Tnbm P540 Fig. 6-31(a) TCP ftp://ftp.cs.sjtu.edu.cn/ybzhang 683 / 110
Computer Networks v4 cs.sjtu 12/21/12 TCP TCP ~ 1 2 SYN(seq=x) SYN(seq=y) SYN(seq=y, ACK=x+1) SYN(seq=x, ACK=y+1) Tnbm P540 Fig. 6-31(b) ftp://ftp.cs.sjtu.edu.cn/ybzhang 684 / 110
Computer Networks v4 cs.sjtu 12/21/12 ULP A ULP B 1 Close to B Connection Closed 8 ULP A Closing 4 5 Closed to B Connection Closed 9 TCP A 2 FIN SEQ 151 SEQ 188,ACK 152 3 FIN SEQ 188;ACK 152 6 7 ACK 189 TCP B TCP [7] ULPupper layer protocol ftp://ftp.cs.sjtu.edu.cn/ybzhang 685 / 110
Computer Networks v4 cs.sjtu 12/21/12 1 TCP ATCP B 2 TCP AFIN1SEQ=151 TCP 3 TCP BTCP AFIN SEQ151SEQ=188ACK=152 4 TCP Bclose 5 TCP B 6 TCP BFIN1SEQ=188ACK=152 7 TCP AACK=189 8 TCP A 9 TCP B ftp://ftp.cs.sjtu.edu.cn/ybzhang 686 / 110
Computer Networks v4 cs.sjtu 12/21/12 TCP TCP TCP TCP TCP TCP TCP ftp://ftp.cs.sjtu.edu.cn/ybzhang 687 / 110
Computer Networks v4 cs.sjtu 12/21/12 TCP TCP TCPTCP window advertisement ftp://ftp.cs.sjtu.edu.cn/ybzhang 688 / 110
Computer Networks v4 cs.sjtu 12/21/12 kill ftp://ftp.cs.sjtu.edu.cn/ybzhang 689 / 110
Computer Networks v4 cs.sjtu 12/21/12 TCP 1~1000 1001~2000 2001~2500 1000 2000 2500 2501~3500 3501~4500 3500 4500 4500 =2500 1000=1500 2000=500 2500=0 2000 2500=2000 3500=1000 4500=0 1000 4500=1000 ftp://ftp.cs.sjtu.edu.cn/ybzhang 690 / 110
Computer Networks v4 cs.sjtu 12/21/12 TCP TCP TCP TCP TCP TCP TCP ftp://ftp.cs.sjtu.edu.cn/ybzhang 691 / 110
Computer Networks v4 cs.sjtu 12/21/12 TCP Tnbm P548 Fig. 6-36 ICMP ftp://ftp.cs.sjtu.edu.cn/ybzhang 692 / 110
Computer Networks v4 cs.sjtu 12/21/12 TCP ftp://ftp.cs.sjtu.edu.cn/ybzhang 693 / 110
Computer Networks v4 cs.sjtu 12/21/12 ftp://ftp.cs.sjtu.edu.cn/ybzhang 694 / 110
Computer Networks v4 cs.sjtu 12/21/12 nn n ftp://ftp.cs.sjtu.edu.cn/ybzhang 695 / 110
Computer Networks v4 cs.sjtu 12/21/12 ftp://ftp.cs.sjtu.edu.cn/ybzhang 696 / 110
Computer Networks v4 cs.sjtu 12/21/12 64K 1/2 ftp://ftp.cs.sjtu.edu.cn/ybzhang 697 / 110
Computer Networks v4 cs.sjtu 12/21/12 64KB 1024(1K) 44 40 36 1 32 (KB) 28 24 2 20 16 12 8 4 0 0 2 4 6 8 10 12 14 16 18 20 22 24 Tnbm P550 Fig. 6-37 Internet ftp://ftp.cs.sjtu.edu.cn/ybzhang 698 / 110
Computer Networks v4 cs.sjtu 12/21/12 TCP TCP TCP TCP TCP TCP TCP ftp://ftp.cs.sjtu.edu.cn/ybzhang 699 / 110
Computer Networks v4 cs.sjtu 12/21/12 TCP ftp://ftp.cs.sjtu.edu.cn/ybzhang 6100 / 110
Computer Networks v4 cs.sjtu 12/21/12 TCP TCP ftp://ftp.cs.sjtu.edu.cn/ybzhang 6101 / 110
Computer Networks v4 cs.sjtu 12/21/12 TCP 0.3 T 0.3 T1 T2 0.2 0.2 0.1 0.1 0 0 10 20 30 40 50 ms 0 0 10 20 30 40 50 ms (a) ftp://ftp.cs.sjtu.edu.cn/ybzhang Tnbm P551 Fig. 6-38 (b) TCP 6102 / 110
Computer Networks v4 cs.sjtu 12/21/12 6-33(a) TCP TCP 6-33(b) ftp://ftp.cs.sjtu.edu.cn/ybzhang 6103 / 110
Computer Networks v4 cs.sjtu 12/21/12 TCP RTT Round-Trip Timer ftp://ftp.cs.sjtu.edu.cn/ybzhang 6104 / 110
Computer Networks v4 cs.sjtu 12/21/12 RTT RTT RTT 0 M 0 RTT = αrtt 0 + (1 - α)m 0 RTT 0 ftp://ftp.cs.sjtu.edu.cn/ybzhang M 0 αrtt 0 M 0 α = 7/8 6105 / 110
Computer Networks v4 cs.sjtu 12/21/12 βrtt RTTββ= 2 D =αd 0 + ( 1 -α) RTT 0 - M 0 = RTT + 4*D ftp://ftp.cs.sjtu.edu.cn/ybzhang 6106 / 110
Computer Networks v4 cs.sjtu 12/21/12 TCP ftp://ftp.cs.sjtu.edu.cn/ybzhang 6107 / 110
Computer Networks v4 cs.sjtu 12/21/12 ftp://ftp.cs.sjtu.edu.cn/ybzhang 6108 / 110
Computer Networks v4 cs.sjtu 12/21/12 Thanks jdyu@cs.sjtu.edu.cn ftp://ftp.cs.sjtu.edu.cn/ybzhang 6109 / 110