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Transcript
Introduction to TCP/IP What is TCP/IP Transmission Control Protocol/Internet Protocol TCP/IP refers to an entire suite of networking protocols, developed for use on the Internet TCP and IP are certainly two of the most important TCP/IP Characteristics TCP/IP provides the services necessary to interconnect computers and to interconnect networks, creating the Internet Independence from underlying network topology, physical network hardware, and OS Unique IP Address Universal connectivity throughout the network Standardize high-level protocols TCP/IP Internetworking Token Ring Router Private Nets and Internet FDDI LAN and Devices LANs are designed to : Operate within a limited geographic area Allow multiaccess to high-bandwidth media Control the network privately under local administration Provide full-time connectivity to local services Connect physically adjacent devices Bridge Hub Ethernet Switch Router ATM Switch Wide-Area Networks and Devices WANs are designed to : Operate over geography of telecommunications carriers Allow access over serial interfaces operating at lower speeds Control the network subject to regulated public services Provide full-time and part-time connectivity Connect devices separated over wide, even global areas Router X.25 or Modem Frame Relay CSU/DSU Switch TA/NT1 S Comm. Server Multiplexor stat mux ATM Switch TCP/IP Networking Software TCP/IP protocol suites define a set of universal communication services Services can be implemented in a standardized manner in the networking software, normally bundled with OS TCP/IP Comm. Software Internet TCP/IP Comm. Software TCP/IP and Internet 1957 USSR sputnik, USA established ARPA 1969 ARPA funded ARPANET 1971 Network with 15 nodes 1974 Cerf/Kahn Protocol 1973 Ethernet (Ph.D Dissertation Bob Metcalfe) 1982/83 TCP/IP as a core protocol 1983 4.2 BSD Unix with TCP/IP from UCB (univ. of California @ Berkley) Internet growth Year 69 84 87 90 91 92 93 94 95 96 #Hosts 4 1024 28174 313000 617000 1.1M 2.0M 3.8M 6.6M 12.8M 97 16M Internet Technical Bodies ISOC - Internet Society. Professional society to promote the use of Internet for research and scholar communication and collaboration IAB - Internet Architecture Board. Technical oversight and coordination, falls under ISOC IETF - Internet Engineering Task force. Current protocols and specifications for standardization. Meets 3 times a year, organized in working groups IRTF - Internet Research Task force. Research oriented for future. Internet Administrations DDN - the USA Defense Data Network is the government organization that has overall responsibilty for administrating the Internet DDN NIC (Network Information Center) IANA Internet Assigned Numbers Authority assigns unique names and addresses collects and distributes information about TCP/IP protocols assigns value for network parameters, name of services, identifiers NOC (Network Operations Center) manages communication links IAB Standard Tracks RFC Internet Draft Circulated technical documents call Request For Comments Revision RFC Proposed Standard protocol specifications should be stable technically and should have no bugs or holes. Draft Standard at least 2 independent and interoperable implementations that test all specification funcions Official Standard have had significant field use and clear community interest in production use. Protocol Status Levels All TCP/IP protocols have one of the following five status levels Required Recommended Elective Limited use Not recommended Internet documents RFC STD (STandDard) number with RFC XXXX, more than 1700 now updated RFCs are published with new RFC numbers not all RFCs describe protocols. not all RFCs are used ftp://ds.internic.net official Internet standard FYI (For Your Information) RFC series that do not contain protocol specifications Sample Documents RFC 2030 I D. Mills, "Simple Network Time Protocol (SNTP) Version 4 for IPv4, IPv6 and OSI", 10/30/1996. (Pages=18) (Format=.txt) (Obsoletes RFC1769) 1879 I B. Manning, "Class A Subnet Experiment Results and Recommendations", 01/15/1996. (Pages=6) (Format=.txt) FYI 0023 Guide to Network Resource Tool. EARN Staff. March 1994. (Format:TXT=235112 bytes) (Also RFC1580) 0028 Netiquette Guidelines. S. Hambridge. October 1995. (Format: TXT=46185 bytes) (Also RFC1855) TCP/IP Architectural Layers Network Applications Application End-to-end Services Transport Routing Internet Network Interface Transmission Network Physical TCP/IP and OSI OSI TCP/IP Application Presentation Application Session Transport Transport Network Internet Data Link Network Physical Physical TCP/IP majors protocols Application Transport FTP TELNET SMTP TFTP NFS NTP SNMP NNTP DNS BOOTP DHCP HTTP X-windows TCP UDP Internet IP Network Network Driver Software Physical Communications Protocols A Communication protocol that provides a data transfer service can be either connection-oriented or connectionless Connection-oriented --A connection is generated before the data is exchanged (e.g. TCP) Connectionless -- Tries its best to delivery data, no need to establish connection (e.g. UDP) Client-Server Relationships FTP Server TELNET Server TELNET Client FTP Cleint FTP Protocol TELNET Protocol FTP Client One application component, called Server, provides welldefined services for application components running, called client Clients make a request for services by transmitting data to the server. Servers reply by sending data back to the client How the server knowns type of services ? TELNET Server TELNET Protocol TELNET Client FTP Protocol FTP Server Port Assignments Applications Servers are known by ports number Port numbers are generally allocated by 0 --not used 1-255 --Reserved ports for well-known services 256-1023 --Other reserved ports 1024-65535 --user-defined server ports FTP 20, TELNET 23, SMTP 25, HTTP 80 Unix stores general used ports in /etc/services directory 1 2 3 4 () () () () Transport Network access