Transcript Telecommunications, Copyright Ralph B. Bisland, Jr, 2001

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Title Slide
Internet Concepts
Telecommunications &
Basic Internet
By
Ralph B. Bisland, Jr.
Client/Server Model
• Basic model of how the Internet operates
• Client/Server Model: Consists of at least two
computer systems:
– Client Computer System
– Server Computer System
Internet Concepts: Telecommunications, Copyright Ralph B. Bisland, Jr, 2001
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Client Computer System
 Runs “locally” (probably on a PC)
 May have different versions for different
platforms
 Initiates requests
 Example client command: Send me
“file-a”
Internet Concepts: Telecommunications, Copyright Ralph B. Bisland, Jr, 2001
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Server Computer System
Runs on remote computer that is
permanently connected to the Internet
Tasks Performed:
 Authorizes users
 Stores and manages data
 Responds to requests from clients
Example server action: Here is the file you
requested
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Client/Server Architecture
Client
Computer
Server
Computer
Data
Communication Link
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Communication
• How computers communicate with each
other (telecommunications)
• Can be either analog or digital
– Analog: A representation of
communication using an analog device
– Digital: A representation of communication using
a digital device
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Analog Data
• Any representation of data in which the
amount of a substance or signal is
proportional to the information represented.
• Examples:
– Watches with hour, minute, and second
hands.
– Gasoline flowing through a punp.
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Analog Communication: Example
• Phonograph-Recording involved cutting
groves into the record analogous to the
vibrations that make sounds. Height of
the “bumps” was proportional to the
loudness of the sound. A needle
traveled across the surface of the
record and as it ran across the “bumps”,
it vibrated a diaphragm, producing
vibrations that humans perceive as
sounds.
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Analog Communication: Example
• Early telephones were analog
devices. Speaker caused an
electronic current to be generated
and transmitted over telephone
line. The louder you talked, the
more current was sent over the
line.
Internet Concepts: Telecommunications, Copyright Ralph B. Bisland, Jr, 2001
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Advantage of Analog
• Easy to understand how it works. The pitch
of a human voice is an exact analog of the
force a person applies to stretch their vocal
cords.
Internet Concepts: Telecommunications, Copyright Ralph B. Bisland, Jr, 2001
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Disadvantages
• Impossible to produce an exact analog of all
possible inputs. (All people do not sing the
same way.)
• Media wears out. (Each time a record is
played, part of the “bumps” are worn away).
• Inaccuracies arise because amplifiers are
not perfect.
Internet Concepts: Telecommunications, Copyright Ralph B. Bisland, Jr, 2001
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Disadvantages (ctd)
• Analog signals fade and must be
re-amplified. Amplifications causes
noise to (called distortion) to creep
into the signal. The more times the
signal is amplified, the more
distortion is added.
Internet Concepts: Telecommunications, Copyright Ralph B. Bisland, Jr, 2001
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Digital Communication
• Information is represented by specific
numbers. These numbers are represented
in binary.
• Data is transmitted with a series of 0’s and
1’s.
• Because computers are basically digital
machines, digital communication works best
with them (no conversion to analog is
needed).
Internet Concepts: Telecommunications, Copyright Ralph B. Bisland, Jr, 2001
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A To D Converters
• Most telephone lines are analog lines.
• Since computers are digital machines,
the digital signal must be converted to
an analog for transmission.
• This is done by an A to D converter
• Specific device is called a modem
modulate-demodulate.
• Process is transparent to end users.
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Example Of The Use Of Modems
Communication Line
Computer
A
Modem 1
Digital Data
Modem 2
Analog Data
Computer
B
Digital Data
Internet Concepts: Telecommunications, Copyright Ralph B. Bisland, Jr, 2001
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Morse Code
• Early telecommunication: Morse Code
• Series of dots and dashes (Min=1, Max=6)
Examples of Morse Code
A:
B:
C:
0:
1:
2:
3:
5:
6:
.:
.-...
-.-.
----.----..--...-.....
-....
.-.-.-
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Morse Code (ctd)
• Telegraphs were digital - either a dot or a
dash
• Experienced telegraphers knew when a
“word break” occurred.
• Telegraph operators “translated” message
into Morse code. Receiving telegrapher
decoded message for receiver
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ASCII Codes
• Modern computer systems do not use
Morse Code to transmit data over the
Internet
• Use ASCII codes (8 binary bits = 1 byte)
• Each character has a specific number
associated with it
A = 0100 0001 = 65 (base 10)
B = 0100 0010 = 66 (base 10)
• Digital representation of data
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Advantages/Disadvantages
• Advantage: Do not “wear out”. Since a
number represents a value, the number
does not “fade”.
• Disadvantage: Since most values are
analog, data must be converted into a
number by some A to D process.
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Telecommunications
• Key to understanding how the Internet
works
• Understanding telecommunications and the
UNIX operating system
• Telecommunications:
– The electronic transmission of data (text,
graphics, sound, and video) over any one
of different communications channels,
such as public telephone lines, private
cables, microwave, or satellite.
• Networks connect a set of computer systems
to each other.
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Types Of Networks
• A network is a series of interconnected
computer systems.
• Two types of networks
– Local Area Networks (LANs)
– Wide Area Networks (WANs)
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LANs
Hardware, software, and communications
equipment that allow computers to be
connected within a limited area.
Limited Area: Within a building or a set of
buildings in close proximity.
Analogy: An “in house” telephone system don’t have to use all digits.
Internet Concepts: Telecommunications, Copyright Ralph B. Bisland, Jr, 2001
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WANs
o Same as a LAN except that the computers
can be anywhere.
o Distance is not a problem.
o Difference is how the computers are
connected.
o Largest WAN is the Internet.
o Analogy: A telephone system to call
anywhere.
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What Is The Internet?
A series of interconnected LAN’s and WAN’s
LAN#1
USM
LAN#2
MSU
WAN#1
MILNET
WAN#2
BITNET
LAN#3
Ole’ MS
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More About LAN’s
• Because of costs, LAN technology differ in
speed of transmission, encoding schemes
for data.
• Various LAN technologies are incompatible
• LAN’s probably do not use modems to
communicate between computers.
• LANs just plug a wire connecting one
computer to another
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More About LAN’s (ctd)
• Can not just plug two LAN’s together
• Operate over a limited distance
• May have its own specification for electrical
signals (voltage and frequency)
• Technology for encoding data may be
different
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More about WANs
• WANs (or long haul networks) probably do
use modems to connect computers
together.
• WAN technologies are also incompatible.
• WAN and LAN technologies are
incompatible.
• WANs use special purpose computers to
resolve incompatibilities between different
WANS.
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Routers
• A special purpose computer that connects
two or more networks and routes data to its
final destination.
• Analogy: An intermediate Post Office.
• A router forwards datagrams to another
router, etc. until the datagram can be
delivered to its final destination
• Routers connect “nodes” on networks
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Routers (ctd)
• Since routers are computers, they have a
finite amount of storage space in which to
store queued messages.
• If the storage space is full (the router has too
many messages to store), the messages can
not fit in the storage spaces are thrown
away.
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How To Connect Them All Together
• ARPA (Advanced Research Products
Agency) allocated money to research the
connectivity problem.
• Came up with a new approach called
“internetwork”.
– internet: approach in general
– Internet: experimental prototype
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The Solution
• ARPANET: A large WAN (called a backbone)
that tied many researcher’s computers
together.
• Agreed upon a standard for packaging data
to transmit to other computers.
• Software consisted of two parts:
– IP: Internet Protocol
– TCP: Transmission Control Protocol
• Produced a smooth seamless method of
transmitting data.
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Example Of A Backbone
N2
N1
R1
R2
N3
R6
R3
Internet
N6
R5
R4
N4
N5
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Protocols
• An agreed upon set of rules on how
something is to be done.
• Examples:
– Red and Green traffic lights
– Answering the telephone
– Transmitting data between computer
systems
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IP- Internet Protocol
• IP: The basic rules of how computers
communicate with each other
• Makes Internet appear to be one big
network
• Data is packaged into fixed size bundles
called packets (general term: datagrams)
• The format of the packet follows the IP
protocol
• Internet computers must have IP software
to code/decode data
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IP Addresses
• Every computer connected to the Internet
must have a unique address
• IP Address Syntax: A quadruple set up in
“dotted notation”
• Example IP addresses:
195.31.115.204 = orca
1100 0011 0001 1111 0111 0111 1110 1100
195.31.82.42 = ocean
• All computers on the same network have the
same prefix
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Domain Name System
• Most people can not remember IP address
numbers
• Domain Name System (DNS): A distributed
database that translates IP address numbers into
names
• Example DNS entries:
195.31.115.204 = orca.st.usm.edu
195.31.82.42 = ocean.otr.usm.edu
• Synonyms: computer aliases
195.31.115.204 = www.cs.usm.edu
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How Data Is Transmitted
• Networks usually do not dedicate a single
wire for each pair of communicating
computers
• Multiple computers share underlying
hardware facilities
• Sharing causes delays
• Sharing is economical
• Sharing is accomplished by taking turns
transmitting data
• Accomplished by packet switching
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Packet Switching
• Computer divides data to be transmitted into
packets
• As packets are created, they are are placed
on the network for transmission.
• Each packet contains a “header”
–
–
–
–
–
To IP address
From IP address
Sequence Number
Checksum total
Other stuff
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Packet Switching (ctd)
• As packets are received, they are placed in
order and the computer distributes them to
the designated “receiver”.
• All packets are not the same size, but there
is a maximum size. Size depends upon the
application - may be a large E-mail message
or a single keystroke.
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TCP/Transmission Control Protocol
•
•
•
•
Insures that data is delivered correctly
Works closely with IP
Collectively called TCP/IP protocol suite
TCP is also software to exists on most
computers connected to the Internet
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How TCP Works
• Sometimes because of network volume,
data is lost.
• Sometimes some of the packets are
received and some are not.
• Because of network traffic, all packets in a
transmission may not travel the same route
to the receiver.
Internet Concepts: Telecommunications, Copyright Ralph B. Bisland, Jr, 2001
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How TCP Works (ctd)
• If all packets are received and the checksum
is correct an acknowledgment is sent back to
the sending computer. If not, a message to
retransmit is sent back to the sending
computer
• Retransmission can result in duplicate
packets being received
• If a duplicate packet is received, it is ignored
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Intranets
• Most organizations that are very security
“aware”
• Some organizations want the capability of
the internet, but only for their employees.
• Solution: An intranet (applications restricted
to a local closed LAN)
• A software “firewall” is created on the LAN
allowing no packets in or out.
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Why Protect Your Computer?
•
•
•
•
•
Viruses
E-mail Viruses
Worms
Trojan Horses
Spyware
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Viruses
• Virus: A small piece of computer
code that is piggybacked onto a
real program.
• It might attach itself to a
spreadsheet, etc. Each time the
spreadsheet is opened, the virus
could spread to other programs.
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How Viruses Spread
• Early viruses were pieces of code that were
attached to a common program (word
processor or computer game).
• When the program started up, the virus
loads itself into main memory and looks for
other executable programs to attach itself to.
• If the program was copied to a floppy disk
and loaded onto another computer, it spread.
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How Viruses Spread (ctd)
• This technique worked for a while
because the virus could write itself out
to floppy disks.
• After a while programs became so
sophisticated they could not fit on one
floppy disk.
• Larger programs were now loaded onto
CDs. CDs can not be written to. This
virus spreading technique faded out.
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Boot Sector Viruses
• To spread, a program that contains the virus
must be started up.
• Virus creators needed a program that was
always executed.
• The “boot sector” of a floppy disk or hard disk
contains the first part of the operating system.
It basically loads the operating system into
memory.
• Viruses began infecting the boot sector
program which is executed when the
computer starts up.
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Boot Sector Viruses (ctd)
• This was a fool proof method of
infecting a computer.
• It was particularly bad on college
campuses as students share computer
resources.
• Executable program and boot sector
viruses are not very threatening any
more as operating systems have built in
methods of eliminating this kind of virus.
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Origins of Viruses
• People create viruses.
• They are a program designed to do
something.
• Once written, the virus is “released”.
• The virus may be simply a nuisance (writing
a message on your screen) or highly
destructive (erasing files on your hard drive).
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Why Create A Virus?
• The same thing that drives vandals and
arsonists. Just for the thrill of being able
to do it.
• The thrill of watching things “blow up”.
Some people like to see accidents or
wrecks.
• Bragging rights. “Hey I created the XYZ
virus and it messed up 10,000
computers.”
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E-mail Viruses
• E-mail viruses: Same as viruses, but
they get spread via inbound E-mail
messages.
• The virus usually attacks the users Email address book by sending itself to
every address in the address book.
Internet Concepts: Telecommunications, Copyright Ralph B. Bisland, Jr, 2001
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How E-mail Viruses Work
• Virus is attached to a down loaded E-mail.
• When the E-mail is opened, the virus is
started up.
• Once opened, the virus has access to the
users address book to ship the virus to
unsuspecting friends of the “victim” – and
the return address is “friendly”.
• E-mail viruses can be spread by opening Emails or attachments to E-mails (actually a
Trojan Horse).
Internet Concepts: Telecommunications, Copyright Ralph B. Bisland, Jr, 2001
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Famous E-mail Viruses
• Melissa (1999): Infected many Microsoft
Word documents. Took advantage of a
programming language built into
Microsoft Word – VBA (Visual Basic for
Applications) which could start up other
programs.
• ILOVEYOU (2000): Came as an
attachment sent with E-mail messages.
Internet Concepts: Telecommunications, Copyright Ralph B. Bisland, Jr, 2001
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Worms
• Worms: A small piece of software that
uses security holes in a network to
replicate itself.
• A copy of the worm scans the network
for security holes. When it finds one, it
enters, replicates itself, then tries to find
other security holes.
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Code Red Worm
• Found security holes in Microsoft SQL
Server and later in Windows NT and
Windows 2000 servers.
• Replicated itself over 250,000 times on July
19, 2003.
• Slowed down network traffic with
replications.
Internet Concepts: Telecommunications, Copyright Ralph B. Bisland, Jr, 2001
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Code Red Worm (ctd)
• Code Red worm was designed to:
– Replicate itself for the first 20 days of each
month
– Replace web pages on infected computers
with a page that declares “Infected by
Chinese”.
– Launch a concerted attack on the White
House web server in attempt to overwhelm
it.
Internet Concepts: Telecommunications, Copyright Ralph B. Bisland, Jr, 2001
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Trojan Horses
• Trojan Horses: This is simply a
program that “disguises” itself to do one
thing, but actually does something else
(like erase your hard disk).
• Trojan horses do not replicate them
selves.
Internet Concepts: Telecommunications, Copyright Ralph B. Bisland, Jr, 2001
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Spyware
• Internet jargon for Advertising Supported
Software (aka adware).
• How shareware authors make money.
• Large media companies offer spyware to
place ads in their products in exchange for
part of the revenue from banner sales.
• You don’t pay for the software and the
advertisers get paid.
• You can have the spyware removes but you
usually have to pay a price for doing this.
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Protection from Intruders
• Virus Protection Programs (such as
Norton Anti Virus.)
• Scans your computer for viruses,
worms, and Trojan horses and either
quarantines or deletes them.
• Scans incoming (and outgoing) E-mail
for viruses.
• You must keep virus definitions
updated.
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Firewalls
• A barrier that protects your computer
from the outside world.
• Analogy: One hole that all traffic into
and out of your computer travels – there
all traffic can be monitored.
• It filters incoming (and outgoing) data.
• Firewalls are customizable.
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Customizing Firewalls
• IP Addresses: All traffic from certain IP
addresses can be blocked (blacklists) or
allowed in (whitelists).
• Domain Names: All traffic from specific
domain names (ex. usm.edu) can be blocked
or allowed in.
• Protocols: All traffic to do certain this is
allowed (get web pages, send and receive Email, etc)
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Customizing Firewalls (ctd)
• Ports: Requests come into computers via
ports. Ex. Port 80 for web pages, port 21 for
FTP requests, etc.. The firewall might only
allow web requests on a certain computer to
come from within the company (i.e., an
Intranet).
• Specific word and phrases: The firewall
will sniff each packet for certain words or
phrases and not allow them into the system.
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What Firewalls Protect You From
• Remote Login: Someone is allowed to
connect to your computer and use it.
• Application Backdoors: Some
programs have special features that
allow remote login. Your system has
bugs in it that allow the user to do
something to your computer.
• SMTP Tracking: Gain access to your
address book which allow them to gain
addition addresses to send spam to.
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What Firewalls Protect You From (ctd)
• Operating System Bugs: This may allow
backdoor access to your computer.
• E-mail Bombs: This is usually a personal
attack on a person or organization. A hacker
sends you many, many E-mails until your
system can not accept any more.
• Macros: Some programs (ex. Excel
spreadsheets) allow you to store mini
programs to perform frequently used tasks.
Hackers create their own macros to wreak
havoc on your computer.
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What Firewalls Protect You From (ctd)
• Denial of Service: A hacker sends a
request for service to a server to
connect to it. When the server responds
with an acknowledgement and tries to
establish a connection, it cannot find the
system that made the request. By
inundating a server with these
unanswerable requests, the hacker
causes the server to slow down and
eventually fail. This is very hard to
prevent.
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What Firewalls Protect You From (ctd)
• Viruses: Enough said.
• Spam: Totally harmless, but annoying
stuff. Electronic junk mail. These may
contain a “cookie” that allows backdoor
access to your computer.
• Redirect Bombs: Hackers can use
ICMP (Internet Message Connect
Protocol) to change the path information
and hence sending replys to a different
router. One way to set up denial of
service.
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What Firewalls Protect You From (ctd)
• Source Routing: In most cases packets are
sent from one location to another by routers
along the path. However, the source
providing the packet can arbitrarily specify
the route the packet is to travel. Hackers can
use this to make packets appear to come
from trusted sources or even inside your
network. Most firewalls simply dispose of
these packets.
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How Most Firewalls Are
Configured
• Block all incoming traffic, then only
allow in what you need.
• Example: Block all requests for service
except E-mail, then heavily filter them.
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Proxy Servers
• Proxy Servers are often used with firewalls.
• Used to access web pages by other
computers.
• When a computer requests a web page, it is
retrieved by the proxy server and then sent
to the requesting computer.
• The net effect of this action is that the
remote computer hosting the Web page
never comes into direct contact with
anything on your home network, other than
the proxy server.
Internet Concepts: Telecommunications, Copyright Ralph B. Bisland, Jr, 2001
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Proxy Servers (ctd)
• Proxy servers can monitor access to web
pages.
• Proxy servers can also make web access
more efficient.
• If you access a web page it is places the
code to create the web page into a special
type very fast memory called cashe
memory.
• The next time you request the page acess is
from cashe memory and not disk.
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DMZ
• Demilitarized Zone.
• If you want to place stuff for all users to
have access to, you can set up a DMZ.
• Things to place in a DMZ:
– Web Pages
– Online business
– FTP site for download and upload
• DMZs are just outside your firewall.
• Analogy: The front yard of your house
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How Computers Are Physically Connected
• No matter how sophisticated a network is, it
must be “physically” connected to the other
computers in the network.
• Bandwidth: The amount of data that can
travel through a circuit expressed in bits per
second. Measure of capacity, not speed.
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Methods of Connecting Computers
•
•
•
•
•
•
•
•
•
Telephone Lines
ISDN (Integrated Services Digital Network)
DSL (Digital Subscribers Line)
Ethernet Lines
Fiber
Radio Waver
Satellites
Cable TV
WAP (Wireless Access Protocol)
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Telephone Line
• Data is transmitted over copper wire.
• Most used because its everywhere.
• Slow in relation to other methods of
data transmission.
• Must use a telephone modem to convert
digital data to analog data and then
analog data back to digital data.
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Telephone Lines (ctd)
• Transmission speed is measured in bits per
second (bps). Old terminology: baud rate.
• Most common transmission rates are:
– 300 bps
– 2400 bps (1)
– 9600 bps (4)
– 14400 bps (6)
– 28800 bps (12)
– 57600 bps (aka 56000) (24)
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ISDN
• Integrated Services Digital Network
• A special type of phone line that can be used for
voice or data (or both)
• Good for organizations that need both voice and
data lines
• Has both analog and digital transmission of data
• Approximately 5 times faster than a 28800
modems
Internet Concepts: Telecommunications, Copyright Ralph B. Bisland, Jr, 2001
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DSL
• Digital Subscribers Line
• Replaces ISDN (much faster and cheaper)
• The DSL signal is mixed in with your
normal phone signal at the phone
companies central office (CO).
• Handles both analog (telephone) and digital
(data) transmission without interfering with
each other.
• Speed: 1.5 - 2 MB/sec
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DSL (ctd)
• Inside your home you must have an external
DSL modem which is connected to a
“splitter”. The “splitter” device separates the
signal.
• Your modem must be connected to your
computer via a NIC (Network Interface Card).
• The signal is sent out to your local phone
company which acts as your ISP.
• Must be close to the source for fast
transmission.
Internet Concepts: Telecommunications, Copyright Ralph B. Bisland, Jr, 2001
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DSL (ctd)
Phone
Company
Splitter
Telephone
Internet
DSL
Modem
Computer
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T1 And T3 Links


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Used to transmit data between LANs and WANs
Very fast method of transmitting data
Use high speed leased telephone lines
Relatively expensive method of transferring data
T1 Link: Capable of sending information at 1.544
MB/sec
 Consists of 28 voice channels of 64 Mbps
 24 - 8 bit packets are transmitted followed by a
synchronization bit (193 bits)
 T3 Link: Capable of sending information at 44.54
MB/sec (28 T1 channels)
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Ethernet Connection
Developed by Digital Equipment Corporation
(DEC) and Xerox Corporation.
Ethernet refers to the wires and the
electronic signals used to transmit data
Only able to transmit at short distances
before signal fades
Analogy: Throw a rock into a pond.
Speed: 100 MB/sec
Mostly used on LANs
Cheap,reliable, and simple.
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Ethernet Connection (ctd)
• Transmission speed much faster than telephone
lines
• Three types of Ethernet lines
– Thick cable - Approximately 1600 feet, 20 mbps
– Thin cable - Approximately 600 feet, 10 mbps
– Twisted pair - Approximately 300 feet, 4-16
mbps
• An Ethernet modem is needed to connect a
computer to an Ethernet line.
• PCMCIA: Personal Computer Memory Card
International Association
– People Can’t Memorize Computer Industry
Acronyms 
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Optical Fiber Connections
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Based on fiber optics technology
Transmits data as pulses of light
Digital transmission
Requires optical modem
Very fast transmission of data
 100 MB per second
 USM campus has fiber cables connecting
some buildings
Internet Concepts: Telecommunications, Copyright Ralph B. Bisland, Jr, 2001
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Cable
• Data is transmitted through a TV cable.
• Speed up to 2MB per second.
• Useful because it is at least 100 times faster
than telephone lines and almost every home
has a cable hookup. Since most telephone
modems transmit at 28.8 KB, cable is about
200 times faster.
• Cable needs a modem to separate the video
from the data.
Internet Concepts: Telecommunications, Copyright Ralph B. Bisland, Jr, 2001
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WAP
• Wireless Access Protocol
• Client computer does not have to be
“physically” connected to the network.
• Uses a beacon to transmit data.
• Range: About 500 yards
• Transmission is done through radio waves.
• Speed: 11MB (soon to be 50MB).
Internet Concepts: Telecommunications, Copyright Ralph B. Bisland, Jr, 2001
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ATM
• Asynchronous Transfer Mode
• A transfer mode in which information is
organized into cells (53 byte packets) and is
asynchronous in the sense that recurrence
of cells containing information from an
individual user is not periodic.
• Used to transmit voice, video, text, pictures.
• Smaller cells so video does not flicker when
transmitted.
• Transmission of information can start at any
time.
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Gigabit Ethernet
• Since most Internet traffic begins and ends
with some type Ethernet connection, a
group of users developed a set of standards
that could be used on LAN and WANs.
• Only works on fiber optic cables.
• Can run at 10 gigabits/sec.
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Point to Point Protocol
• PPP: Point-To-Point Protocol
• Function of PPP: Most modems assume
that a dumb terminal (VDU + keyboard) is
used to connect to a host computer systems
and provides only limited "services".
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Point to Point Protocol (ctd)
• PPP allows the host computer to
recognize the "computer" connection.
• It allows more functionality.
• In order to use some of the Internet
features (i.e. transmitting graphics),
you must have PPP protocols.
Internet Concepts: Telecommunications, Copyright Ralph B. Bisland, Jr, 2001
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Post Office Protocol
• Post Office Protocol Version 3 is usually
written as PoP2.
• Works like an old time Post Office. People
did not get mail delivery at their homes (too
expensive). Their mail went to a Post Office
and when the people were near the Post
Office they went in and picked up their mail.
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Post Office Protocol (ctd)
• PC usually can not serve as a mail
server – they are not connected to the
Internet, they don’t have ginormus
memory to store queued up mail, etc.
• The PoP server provided the function of
storing messages for the user. When
the user logs on to their computer and
checks their mail, all of the queued up
mail is delivered.
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Who Owns The Internet?
Nobody - The Internet simply exists!!!!
The Internet exists like a common carrier (i.e.
the telephone company)
Some (but not many) Federal Laws exist to
police it in the U. S.
Example: Telephone company can not
dictate to a organization how to run their
business. (You can have a phone if you run
your business a particular way.)
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Who Owns The Internet? (ctd)
Almost no requirements that you
must obey certain rules to connect
to the Internet.
Local network administrators are
generally responsible for managing
it.
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Internet Society
U. S. governing body of the
Internet: Internet Society (well, kind
of anyway)
Acts as a clearinghouse and gentle
guardian to help maintain
cooperation among Net members particularly on technical standards.
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Connecting To The Internet
• Full time IP connection
– Computers that reside on a LAN that is
connected to the Internet via a router.
– Could be connected to the Internet via a
dedicated telephone line
• Dial up access to a computer on the internet
– Connected to the Internet via a terminal
emulation package
– Not running TCP/IP - can not run programs
directly from a PC
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Connecting To The Internet (ctd)
• Running Internet protocols over
dial-up
– Runs programs from PC via PPP
• Cable
• WAP: Through cell phones or PDAs
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Internet Service Providers (ISPs)
 Your “ramp” onto the Internet
 Local Internet Service Providers:
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USM (Faculty, Students, & Staff)
Netdoor
Comcast (cable)
Cybergate
Megagate
 Look in your Yellow Pages under ISPs
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Typical Connection To The Internet
Client
User #1
Client
User #2
Internet
Service
Provider
The
Internet
Client
User #3
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Internet2
• A consortium of 205 universities working in
partnership with government and industry to
develop and deploy advanced network
applications and technologies, accelerating
the growth of tomorrow’s Internet.
• Internet2 is creating a partnership of
academia, industry, and government that
fostered the Internet in it’s infancy.
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Goals of Internet2
• Create a leading edge network
capability for the national research
community.
• Enable revolutionary Internet
applications.
• Ensure the rapid transfer of new
network services and applications to the
broader Internet community.
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USM’s Connection To The Internet
• USM uses Internet 2
– Uses a WAN connection
– Trunks to:
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•
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•
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Gulf Coast Research Lab
Gulf Park campus
Marine Education Center
Jackson County campus
Keesler AFB campus
Stennis Space Center
JCJC
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USM’s Connection to the Internet
• USM uses its state contract for its local
service provider
• Aberline is its Internet 2 PVC
(Permanent Virtual Circuit) provider
• Cost to USM
– About $50,000 per year
– Plus the T! lease line cost per mile (in 2000
it was $7/mile/month – about $700 per
month).
• Post Office analogy
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How USM Is Connected To The World
• Currently in the process of redesigning it.
• Now an ATM is used.
• Going to a Gigabit network backbone
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ATM Design (current)
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•
•
From orca to a primary router in TEC bldg.
From there to an Ethernet bridge in TEC bldg.
From there to a core campus ATM Switch in TEC bldg.
From there to a campus ATM router in TEC bldg.
From there to a campus primary ATM router in the FCH
bldg.
From there to a campus firewall.
From there to a core campus ATM Switch in the WFS bldg.
From there to a campus core Router in the WFS bldg.
From there through a campus core ATM Switch in WFS out
to PoP link in Jackson.
From there to the outside world.
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Gigabit Design (future)
• From orca to a 10/100 switch in the TEC bldg.
• From there to one of either the primary or secondary
router in either TEC or FCH bldg.
• From ther to a Gigabit switch in the TEC bldg.
• From there to a core Gigabit switch in the FCH bldg.
• From there to the campus Firewall.
• From there to a campus core ATM Switch out to PoP
line in Jackson.
• From there to the outside world.
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Operating Systems
• A program that allows the hardware of
the computer to be used.
• Some functions of an operating system:
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Scheduling programs for execution
Memory management
File management
Communications
• Common Operating Systems
– Disk Operating System (DOS) -- IBM PC (and clones) based
Microsoft Disk Operating System (MS-DOS)
– Windows/Windows 95/Windows NT/MR/XP - IBM PC (and
clones) Based
– OS X - Macintosh based
– UNIX - Mainframe/Minicomputer based (multiuser systems)
– Linux: PC version of UNIX
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Using Computers On The Internet
• When you wish to use the Internet, you may
use it in two different ways
– By using client programs from your PC.
• All the "dirty work" (behind the scenes stuff) is
handled by your client program.
• Easy to use.
• Limited to what you can do (Only what menus allow)
• Inflexible.
– By using a PC to connect to a mainframe and
using UNIX commands to access Internet
resources.
• Much more powerful and flexible.
• Must learn some UNIX commands.
• Harder to use.
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