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Introduction to TCP/IP
What is TCP/IP
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Transmission Control Protocol/Internet Protocol
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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
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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
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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
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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)
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IANA Internet Assigned Numbers Authority
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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)
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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
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Required
Recommended
Elective
Limited use
Not recommended
Internet documents
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RFC
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STD (STandDard)
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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
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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
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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)
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Client-Server Relationships
FTP
Server
TELNET
Server
TELNET
Client
FTP
Cleint
FTP Protocol
TELNET Protocol
FTP
Client
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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
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Port numbers are generally allocated by
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0 --not used
1-255 --Reserved ports for well-known services
256-1023 --Other reserved ports
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1024-65535 --user-defined server ports
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FTP 20, TELNET 23, SMTP 25, HTTP 80
Unix stores general used ports in /etc/services
directory
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() () () ()
Transport
Network access