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 1970 December 1970 August 1972 June 1974 July 1976 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 BIG Cable Step 1 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