Introduction to TCP/IP 4/11/40 page 1 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 4/11/40 page 2
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 Standardie high-level protocols 4/11/40 page 3 TCP/IP Internetworking Token Ring Private Nets and Internet Router FDDI 4/11/40 page 4
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 Ethernet Bridge Hub Router Switch ATM Switch 4/11/40 page 5 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 Frame Relay Switch Modem CSU/DSU TA/NT1 Comm. Multiplexor ATM Switch S stat mux 4/11/40 page 6
TCP/IP Networking Software TCP/IP protocol suites define a set of universal communication services Services can be implemented in a standardied manner in the networking software, normally bundled with OS TCP/IP Comm. Software Internet TCP/IP Comm. Software 4/11/40 page 7 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 Disssertation Bob Metcalfe) 1982/83 TCP/IP as a core protocol 1983 4.2 BSD Unix with TCP/IP from UCB 4/11/40 page 8
Internet growth Year #Hosts 69 4 84 1024 87 28174 90 313000 91 617000 92 1.1M 93 2.0M 94 3.8M 95 6.6M 96 12.8M 1/97 16M 4/11/40 page 9 Internet Technical Bodies ISOC - Internet Society. Professional society to promote the use of Internet for research and scholar communication and collaboration IAB - Internet Archtecture Board. Technical oversight and coordination, falls under ISOC IETF - Internet Engineering Task force. Current protocols and specifications for standardiation. Meets 3 times a year, organied in working groups IRTF - Internet Research Task force. Research oriented for future. 4/11/40 page 10
Internet Administrations DDN - the USA Defense Data Network is the government organiation that has overall responsibilty for administrating the Internet DDN NIC (Network Information Center) assigns unigues names and addresses collects and distributes information about TCP/IP protocols IANA Internet Assigned Numbers Authority assigns valur for network parameters, name of services, identifiers NOC (Network Operations Center) manages communication links 4/11/40 page 11 IAB Standard Tracks RFC Circulated technical documents call Request For Comments Internet Draft Revision RFC Proposed Standard Draft Standard Official Standard protocol specifications should be stable technically and should have no bugs or holes. at least 2 independence and interoparable implementation that test all specification funcions have had significant field use and clear communinity interest in production use. 4/11/40 page 12
Protocol Status Levels All TCP/IP protocol have one of the following five status levels Required Recommended Elective Limited use Not recommended 4/11/40 page 13 Internet documents RFC number with RFC XXXX, more than 1700 nows updated RFCs are published with ne RFC numbers not all RFCs describe protocols. not all RFCs are used ftp://ds.internic.net STD (STandDard) official Internet standard FYI (For Your Information) RFCs series that do not contain protocol specifications 4/11/40 page 14
Sample Documents RFC FYI 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) 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) 4/11/40 page 15 TCP/IP Architectural Layers Network Applications Application End-to-end Services Routing Network Interface Transmission Transport Internet Network Physical 4/11/40 page 16
TCP/IP and OSI OSI Application Presentation Session Transport Network Data Link Physical TCP/IP Application Transport Internet Network Physical 4/11/40 page 17 TCP/IP majors protocols Application TELNET SMTP T NFS NTP SNMP NNTP DNS BOOTP DHCP HTTP X-windows Transport TCP UDP Internet Network Physical IP Network Driver Software 4/11/40 page 18
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 -- Try its best to delivery data, no need to establish connection (e.g. UDP) 4/11/40 page 19 Client- Relationships TELNET TELNET Client )73 3URWRFRO 7(/1(7 3URWRFRO 7(/1(7 3URWRFRO Client TELNET TELNET Client One application component, called, provides a welldefined services for application components running, called client Clients make a request for a services by transmitiing data to the server. Cleint Cleint )73 3URWRFRO )73 3URWRFRO s reply by sending data back to the client How the server knowns type of services? 4/11/40 page 20
Port Assignments s are known by ports number 20, TELNET 23, SMTP 25, HTTP 80 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 Unix store general used port in /etc/services Applications 1 2 3 4 ( ) ( ) ( ) ( ) Transport Network access 4/11/40 page 21