1. Introduction to TCP/IP

2. 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

3. 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

4. TCP/IP Internetworking
Token
Ring
Router
Private Nets
and Internet
For many businesses, today’s networks are mixture of old and new technologies. IBM networks might be operating virtually in parallel with the newer LAN interconnected networks, electronic commerce, and messaging systems. Local networks, public data networks, leased lines, and high-speed mainframe channels have all been used on an opportunistic basis with little regard for overall integration and consistency. Application migrating from central hosts to distributed servers has resulted in new networking requirements and changing traffic patterns.
The approach to computer communications in most organizations is changing rapidly in response to new technologies, evolving business requirements, and the need for “instant” knowledge transfer. To meet these requirements, the internetwork, whatever form it takes, must be flexible, scalable, and adaptable to suit any organizational level (branch, region, headquarters).
Internetworks tie LANs and WANs, computer systems, software, and related devices together to form the corporate communications infrastructure. An internetwork moves information anywhere within a corporation and to external suppliers and customers. By serving as the organization’s information highway, the internetworks has become a key strategic asset and a competitive advantage.
FDDI

5. 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
Most of the network administrator’s tasks deal with local area networks (LANs). Major characteristics of LANs follow:
The network operates within a building or floor of a building. The geographic scope for ever more powerful LAN desktop devices running more powerful applications is for less area per LAN.
LANs provide multiple connected desktop devices (usually personal computers) with access to high-bandwidth media.
An enterprise purchases the media and connections used in the LAN; the enterprise can privately control the LAN as it chooses.
LANs rarely shut down or restrict access to connected workstations; local services are usually always available.
By definitions, the LAN connects physically adjacent devices on the media. LAN devices include
Bridges that connect LAN segments and help filter traffic
Hubs that concentrate LAN connection and allow use of twisted pair copper media
Ethernet switches that offer full-duplex, dedicated bandwidth to segments or desktops
Routers that offer many services including internetworking and broadcast control
ATM switches that provide high-speed cell switching
Ethernet
Switch
ATM
Switch
Bridge
Hub
Router

6. 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
Most of the network administrator’s wide-area network(WAN) tasks deal with remote access to distributed locations. Major characteristics of WANs follow:
The network operatesbeyond the local LAN’s geographic scope. It uses the services of telecommunications carriers like Regional Bell Operating Companies (RBOCs).
LANs provide serial connections (usually over a LAN-to-WAN device) with access to lower speed bandwidth.
An enterprise pays the carrier or service provider for connections used in the WAN; the enterprise can choose which services it uses; carriers are usually regulated by tariffs.
WANs rarely shutdown, but since the enterprise must pay for services used, it might restrict access to connected workstations. All WAN services are not available in all locations.
By definitions, the WAN connects devices separated by wide areas. WAN devices include
Routers that offer many services including internetworking and WAN interface controls
X.25 or Frame Relay switches that connect to public data communications services
Modems that interface voice-grade services; Channel Service Units / Data Service Units (CSU/DSU) that interface T1/E1 services; Terminal Adapters / Network Termination 1 (TA/NT1) that interface Integrated Services Digital Network (ISDN) services
Communication servers that concentrate dial-in and dial-out user communications
Multiplexors that share a WAN facility among several demand channels
Asynchronous Transfer Mode (ATM) switches that provide high-speed cell switching S
X.25 or
Frame Relay
Switch
Modem
CSU/DSU
TA/NT1
Comm.
Server
ATM
Switch
Router
Multiplexor
stat
mux

7. 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
Internet
TCP/IP
Comm.
Software
TCP/IP
Comm.
Software

8. 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
BSD Unix with TCP/IP from UCB (univ. of Berkley)

9. Internet growth Year #Hosts 69 4 84 1024 87 28174 90 313000 91 617000 M M M M M M

10. 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.

11. 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)
assigns unique names and addresses
collects and distributes information about TCP/IP protocols
IANA Internet Assigned Numbers Authority
assigns value for network parameters, name of services, identifiers
NOC (Network Operations Center)
manages communication links

12. IAB Standard Tracks RFC Internet Draft Proposed Standard
Circulated technical documents call Request For Comments
RFC
Internet Draft
Revision RFC
protocol specifications should be stable technically and should have no bugs or holes.
Proposed Standard
at least 2 independent and interoperable implementations that test all specification funcions
Draft Standard
Official Standard
have had significant field use and clear community interest in production use.

13. Protocol Status Levels
All TCP/IP protocols have one of the following five status levels
Required
Recommended
Elective
Limited use
Not recommended

14. Internet documents RFC STD (STandDard) FYI (For Your Information)
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
STD (STandDard)
official Internet standard
FYI (For Your Information)
RFC series that do not contain protocol specifications

15. 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)
FYI
0023 Guide to Network Resource Tool. EARN Staff. March (Format:TXT= bytes) (Also RFC1580)
0028 Netiquette Guidelines. S. Hambridge. October (Format: TXT=46185 bytes) (Also RFC1855)

16. TCP/IP Architectural Layers
Application
Network
Applications
End-to-end
Services
Transport
Internet
Routing
Now you have reviewed the evolution leading to the modern networks. You have seen the use of a model and been introduced to the operations and functions at each layer. The remaining three chapters of this Introduction to Internetworking (I2I) module will proceed as follows:
Applications and Upper Layers - Network applitions layers and how they provide application, data presentation, and session functions; also the upper layer that provides end-to end services between hosts using transport layer services.
Physical and Data Link Layers - Data transmission services provided by lower layer functions, with specific variations for LAN and WAN framing and media.
Network Layer and Path Determination - Routing using Layer3 services of the network layer, and other processes; thi is the primary domain of the router.
Network Interface
Network
Transmission
Physical

17. TCP/IP and OSI OSI TCP/IP Application Presentation Session Transport
Network
Data Link
Physical
Application
Transport
Internet
Network
Physical

18. TCP/IP majors protocols
Application
FTP TELNET SMTP TFTP NFS NTP SNMP NNTP
DNS BOOTP DHCP HTTP X-windows
Transport
TCP UDP
Internet IP
Network
Network Driver Software
Physical

19. 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)

20. Client-Server Relationships
FTP Protocol
FTP
Server
FTP
Client
One application component, called Server, provides well- defined 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 Protocol
TELNET
Server
TELNET
Server
TELNET Protocol
TELNET
Client
TELNET
Client
FTP Protocol
FTP
Cleint
FTP
Server

21. Port Assignments Port numbers are generally allocated by
Applications
Transport
Network access
( ) ( ) ( ) ( )
Servers are known by ports number
FTP 20, TELNET 23, SMTP 25, HTTP 80
Port numbers are generally allocated by
0 --not used
Reserved ports for well-known services
Other reserved ports
user-defined server ports
Unix stores general used ports in /etc/services directory