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1、Internet Protocol,Overview,1.0TCP/IP and the DoD Model 2.0IP Addressing 3.0Subnetting,1.0TCP/IP and the DoD Model,1.1Comparison of Dod and OSI Model 1.2The TCP/IP protocol suite 1.3The Process / Application layer Protocols 1.4The Host-to-Host Layer Protocols 1.5The Internet Layer Protocols,1.1Compar
2、ison of DoD and OSI Model (1),The TCP/IP suite was created by the DoD The DoD model is a condensed version of the OSI model,Application,Presentation,Session,Transport,Network,Data Link,Physical,Process / Application,Host-to-Host,Internet,Network Access,DoD Model,OSI Model,Node-to-node application co
3、mmunication Controls user-interface specifications,Setting up the level of transmission service for applications,Takes care IP address and designate protocols for logical transmission of packets over the entire network,Oversees hardware addressing and defines protocols for the physical transmission
4、of data,1.1Comparison of DoD and OSI Model (2),TCP/IP Model,OSI Model,1.2The TCP/IP Protocol Suite,Process / Application,Telnet,TCP,UDP,IP,ICMP,ARP,LAN Technologies: Ethernet, Fast Ethernet, Token Ring, FDDI,WAN Technologies: Serial Lines, Frame Relay, ATM,RARP,Host-to-Host,Internet,Network Access,F
5、TP,TFTP,SMTP,LPD,SNMP,NFS,X Window,BootP/ DHCP,DNS,IGMP,1.3The Process / Application Layer Protocols,Telnet Telephone Network FTP Protocol TFTP Trivial Protocol NFS Network SMTP Simple Mail Transfer Protocol LPD Line Printer Daemon X Window writing a GUI-based client/server applications DNS Domain N
6、ame Service (DNS) BootP Bootstrap Protocol DHCP Dynamic Host Configuration Protocol,1.4The Host-to-Host Layer Protocols,To shield the upper-layer applications from the complexities of the network TCP (Transmission Control Protocol) Break down data from upper layers into Segment Numbers and sequences
7、 each segment Connection-oriented virtual circuit required User Datagram Protocol (UDP) Break down data but not sequence the segment Thin protocol which doesnt take up much bandwidth on a network Connectionless no virtual circuit required, thus unreliable For sending little message and reliability a
8、ccomplished at the upper layers,1.4aTransmission Control Protocol (TCP),Connection-oriented Session is established before exchanging data Virtual circuit required Reliable Delivery Sequence numbers Acknowledgments (ACKs) Doesnt trust the lower layers and runs its own CRC Uses Port Numbers as Endpoin
9、ts to Communicate,1.4bTCP Three-Way Handshake,Application,Transport,Internet,Network,Data,Application,Transport,Internet,Network,Data, ACK (+start byte),ACK,1.4cTCP Segment Format,1.4dUser Datagram Protocol (UDP),Connectionless No session is established Does Not Guarantee Delivery No sequence number
10、s No acknowledgments Low overhead Reliability Is the Responsibility of the Application Doesnt trust the lower layers and runs its own CRC Uses Port Numbers as Endpoints to Communicate,1.4eUDP Segment Format,Low overhead No sequence number No Acknowledgement number No windows size,Transport,Applicati
11、on,Internet,Network,1.4fPorts Numbers (1),TCP and UDP must use port numbers to communicate with the upper layers. Port numbers keep track of different conversations crossing the network simultaneously.,0 . . . 65535,0 . . . 65535,TCP Ports 20,21,UDP Port 69,TCP Port 80,Windows Sockets Interface,TCP
12、Protocol No. 6,UDP Protocol No. 17,IP,TCP Port 25,UDP Port 53,UDP Port 110,UDP Port 161,1.4gPort Numbers (2),No. below 1024 Well-known port no. defined in RFC 1700 Usually in destination port to tell the receiving host the purpose of the intended connection No. 1024 and above used by upper layers (r
13、andomly chosen) to set up sessions with other hosts Used by TCP to use as source and destination addresses in the TCP segment Usually in Source port to differentiate between sessions with different source hosts,1.5The Internet Layer Protocols,For routing and providing a single network interface to t
14、he upper layer layers. All network paths through the model go through IP. Protocols works at the Internet Layer: Internet Protocol (IP) essentially is the Internet Layer, and other protocols found here merely exist to support it. Internet Control Message Protocol (ICMP) Address Resolution Protocol (
15、ARP) Reverse Address Resolution Protocol (RARP),1.5aInternet Protocol (IP),Addresses and Routes Packets according to the Routing Table Fragments and Reassembles Datagrams / Packets Connectionless No session is established Nonguaranteed “Best Effort” Delivery Reliability Is the Responsibility of High
16、er-Layer Protocols and Applications,1.5bIP header,* Protocol number: 01 ICMP, 06 TCP, 17 UDP, etc.,1.5cInternet Control Message Protocol (ICMP),Management Protocol and messaging service provider for IP. In router solicitation, ICMP is used to send the following events and messages (in the Data area): Destination Unreachable Buffer Full Hops Ping Traceroute,1.5dAddress Resolution Protocol (ARP),Successful Mapping of an IP Address to a Hardware Address ARP Uses a Local Broadcast
