Transcript File - MBA 506

The Internet:
What is it? How does it work?
There are supposedly at least 14 billion pages on the internet and, as per
Smithsonian, “from every single one of these pages you can navigate to any other
in 19 clicks or less.”
A History of Internet Connectivity: 1970s
December 1969
June 1974
June 1970
December 1970
July 1976
August 1972
July 1977
Source: http://som.csudh.edu/cis/lpress/history/arpamaps/
A History of Internet Connectivity: TODAY!
How many Internet Users are there?
http://www.internetlivestats.com/internet-users/
1993!!!
So what is this thing we call….the Internet
Internet Service Providers
• You first connect to an ISP and then to the Internet!!
• The ISP then connects you to the Internet
• Remember the YouTube example about crazy Aunt Ruth
Step 2
What do these Big Cables look like?
Interactive Cable Map!!!: http://www.submarinecablemap.com/
Video: Here's what
it takes to lay
Google's 9,000km
undersea cable
Anatomy of a URL
• URL: uniform resource locator.
Identifies resources on the internet
along with the application protocol
needed to retrieve it
• Protocol: set of rules for
communication—sort of like grammar
and vocabulary in a language like
English
• Other Protocols:
•
SMTP, FTP, IMAP
Host Names, Domain Names, Domain
• hostname: the place/computer you
are looking for on a network
• domain name and domain: name of a
network associated with an
organization, and the type of network
•
In the USA, we use: org-name.org-type
• Example: http://mis320.weebly.com
•
•
•
•
http = Hypertext Transfer Protocol
mis320 = hostname
weebly = domain name
.com = Commercial organization
Path and File Names
• Path: a folder location
• File: the file within the folder
•
files are usually written in the hypertext
markup language (HTML), which is
basically the language of the web
• Example:
• tech/index.html
• Tech = technology folder
• index.html = name of file
IP Addresses
• IP Address: where you live on the Internet;
Unique series of numbers that identify
computers on the Internet
•
•
•
you get an IP address from the organization you
are connected to the internet through
At home, your ISP assigns you an IP address
At WWU, Western’s ISP assigns you one
• No two computers have the same IP address
• IPv4 Examples: (composed of 4 segments) WE
ARE RUNNING OUT!!!
•
•
•
72.246.51.15 = www.nasa.gov
152.91.56.138 = www.gov.au
208.185.127.40 = www.about.com
• IPv6 Examples: (composed of 8 segments)
•
•
3ffe:1900:4545:3:200:f8ff:fe21:67cf
21DA:D3:0:2F3B:2AA:FF:FE28:9C5A
The Domain Name Service
• People don’t remember IP Addresses
do they use words (google.com,
wwu.edu, etc.)
•Domain Name Service: a distributed
database that looks up the host and
domain names that you enter and
returns the actual IP address for the
computer that you want to
communicate with
Watch it all come together
What do we know so far….
 how to read a Web address
 every device connected to the Net
needs an IP address
 the DNS can look at a Web address
and find the IP address of the machine
that you want to communicate with
• But..
How does a Web page, an e-mail, or an iTunes
download actually get from a remote computer to
your desktop????
TCP/IP
• Webpages, videos, pictures, are TOO
BIG!!!!
•TCP: works its magic at the start and
endpoint of the trip—on both your
computer and on the destination
computer you’re communicating with
•
•
TCP slices up the web page into small
chunks of data called packets
Packets: smaller pieces of information
containing part of an entire transmission
• IP: route the packets to their final
destination
A Packet’s Tale
HOA#7: Internet Security