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Getting Connected. CECS 5030 with Cathie Norris, Jennifer Smolka & Gerald Knezek. The Internet Today. Worldwide network of networks Government agencies, educational institutions, hospitals, and commercial organizations. The Internet Today. Phenomenal growth - 1 million/month - PowerPoint PPT Presentation
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Getting ConnectedCECS 5030
with Cathie Norris, Jennifer Smolka & Gerald Knezek
The Internet Today
Worldwide network of networks
Government agencies, educational institutions, hospitals, and commercial organizations
The Internet Today
Phenomenal growth - 1 million/month
End of 2001 – 500 million users
Largest connection of networks in the world
How the Internet Works
Local connection via modem, leased-line, ISDN, etc.
Router at provider’s point-of-presence
How the Internet Works
Small providers buy from big providers NorthwestNet NorthwestNexus
Big providers interconnect with each other MCI Sprint AT&T
MCI AT&T
NWNET NWNEXUS
The Internet uses TCP/IP
Share common protocol TCP/IP
Transmission Control Protocol/Internet Protocol
“/” means it operates at two levels
TCP IP
The Internet uses TCP/IP
Created more than thirty years ago by the Department of Defense Advanced Research Projects Agency (DARPA)
TCP/IP is the still the basis for the Internet
The Internet uses TCP/IP
IP Address – unique identifier
IP resides in the Network Layer
TCP resides in the Transport Layer
TCP/IP
Network Protocols Internet Protocol (IP)• Every computer on the Internet has a
unique number which is the destination point• Where you are and how I get there
Transmission Control Protocol (TCP)• How is my data getting between you
and me
TCP/IP
Application Protocols Terminal Emulation (Telnet) HyperText Transfer Protocol (HTTP) File Transfer Protocol (FTP) Simple Mail Transfer Protocol (SMTP) Simple Network Management Protocol
(SNMP) Domain Name Service (DNS)
TCP/IP in the OSI Model
ApplicationPresentationSessionTransportNetworkLogical LinkPhysical
FTP, Telnet
TCP UDPIP ARP
LLCEthernet, WAN, Token Ring, FDDI
SNMP TFTPNFS
Seven Layer Open System Interconnect Model
TCP/IP in the OSI Model
ApplicationPresentationSessionTransportNetworkLogical LinkPhysical
FTP, Telnet
TCP UDPIP ARP
LLCEthernet, WAN, Token Ring, FDDI
SNMP TFTPNFS
Internet Protocol (IP)
IP is a connectionless service that provides basic datagram delivery services.
IP takes care of addressing, or making sure the routers know what to do with your data when it arrives.
Internet Protocol (IP)
Not everything is sent over the Internet is not sent as a BATCH – or complete file
Sent over as packet of smaller pieces
256 characters or 512 characters (maybe longer)
Internet Protocol
Every computer on the Internet has a unique address.
Information sent across IP networks is broken up into bite-sized pieces, called packets.
The information within a packet is usually between 1 and about 1500 characters long.
IP Envelopes
From: 192.112.36.5
To: 128.174.5.6IP Packet
DATA
Internet Protocol
Some addressing information goes at the beginning of your message; this information gives your network enough information to deliver the packet of data.
Internet addresses consist of four numbers each less than 256.
192.112.36.5 128.174.5.6
Internet Protocol
IP Addresses Class A Networks: 128.x.x.x Class B Networks: 146.79.x.x Class C Networks: 192.100.10.x
IP addresses are running out - Extensions to the current IP address protocol will be required - IPng
Transmission Control Protocol
Reliable TCP takes the information you want to
transmit and breaks it into pieces. TCP numbers each piece so receipt can
be verified and the data can be put back in the proper order.
Acknowledgments
TCP Packet Encapsulation
DATA
To: 128.174.5.6
Bytes 1 to 500
TCP Packet
From: 192.112.36.5To: 128.174.5.6
IP Packet
SLIP and PPP
Extensions of IP over voice-grade modem lines:
Serial Internet Protocol (SLIP) Point-to-Point Protocol (PPP)
Allow internet access from the PC in your home by dialing up over modems to an Internet host.
TCP/IP Applications/Services
Terminal Emulation (Telnet)
File Transfer Protocol (FTP)
HyperText Transfer Protocol (HTTP)
Simple Mail Transfer Protocol (SMTP)
Simple Network Management Protocol (SNMP)
Domain Name Service (DNS)
Terminal Emulation (Telnet)
Telnet is the login and terminal emulation program for TCP/IP environments
Primary function is to allow users to log into remote host systems
Requires username and password
How to Telnet
Open your DOS prompt Type telnet Your telnet window opens...
Uses for Telnet Today
Use of Telnet has diminished in recent years
Still being used to: Connect to routers Remote management of
servers Access to home system
while traveling
File Transfer Protocol (FTP)
Important for building web pages
Primary mode of moving complete file from one computer to another
FTP is a program for transferring files in TCP/IP environments (ASCII or Binary)
File Transfer Protocol (FTP)
Client – when you want information
Server – when you have the information
Typically, a user at a client computer downloads files from a remote server
FTP Terms: DOS
GET (MGET): You are downloading a file (or files) from another computer to your desktop
PUT (MPUT): You are uploading a file (or files) from your desktop to another computer
File Transfer Protocol (FTP)
Must logon to server
Requires username and password to access normal file system
Anonymous FTP allows access to anyone to a special file system (e.g. ftp.microsoft.com)
FTP Terms: DOS
CD: Change Directory Move up or down the directory structure
MD: Make Directory New storage space
FTP Transparent
Often FTP commands are transparent through your browser or through a FTP
program like WS FTP.
HyperText Transfer Protocol
Primary application protocol that underlies the world wide web
Provides user access to the files that make up the web
Anywhere – anyplace – anytime
HyperText Transfer Protocol
Defines HOW they get there, not what they look like
Files can be in many different formats (text, graphics, audio, video, etc.)
Hypertext markup language (HTML) is the standardized language for creating web pages
Simple Mail Transfer Protocol
SMTP is the electronic mail transfer protocol used in TCP/IP environments
Provides a store-and-forward mail capability between host computer mail systems on the network
MIME (Multimedia Internet Mail Exchange) has become the standard for document attachments
Domain Name Service
DNS is a TCP/IP service that maps network address numbers, for example, 123.456.789, to an easy to remember name, such as:
Internet and TCP/IP applications such as telnet, FTP and SMTP access DNS to locate names you’ve specified and resolves them to a numeric address and inserts it into a message for transport.
www.microsoft.com
Domain Name Service
The address information is stored at many locations in a hierarchical structure, not at one central depository
Each site has a domain server that maintains information about the local nodes
Central Hub
Node Node
Node Node
Client/Server Architectures
Two-tier “Fat” Client: User Interface + Application Database Server Example: File servers, SQL Servers
Client/Server Architectures
Three-tier “Thin” Client: User Interface only Application Server Database Server Examples: Mail servers, Business
applications
Client/Server Architectures
Application Programming Interfaces SQL, ODBC APPC TP Monitors RPC
Interface Definition Languages DCE CORBA Microsoft OLE
References
From Networking 101Jim Cabral, Puget Technology Group, Inc. &
Tammy Ruth, Children’s Hospital and Medical Center
[email protected] [email protected]
www.pugettech.com