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What is the Internet? What is the Internet? A global network of networks What is the Internet? A global network of networks, including their wires, fibers, and routers (switches) What is the Internet? A global network of networks, including their wires, fibers, and routers (switches)
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What is the Internet? • A global network of networks
What is the Internet? • A global network of networks, including their wires, fibers, and routers (switches)
What is the Internet? • A global network of networks, including their wires, fibers, and routers (switches)
What is the Internet? • A global network of networks, including their wires, fibers, and routers (switches) • The computers connected to each network
What is the Internet? • A global network of networks, including their wires, fibers, and routers (switches) • The computers connected to each network • A book of “IP” addresses that tells each computer where all the others are
IP??? • IP = Internet Protocol – routes the packets • TCP = Transmission Control Protocol arrives in reliable order TCP/IP describes the rules for transmitting small packets of bits (0s and 1s) from one computer to another.
What’s in the packets… Here are the minimum things each needs: • An address (IP number) • An addressee, e.g., someone@… • Something to indicate order or sequence • A portion of the message (Why not all?…) How would that work here?…
Delivering the message… How would that work here in LC 24?… • We need an address: 24.2.9.7 And right away we’re stuck. What does this mean? How do we find out?… • We need a DNS server, which we’ll use in reverse… going from “number” to “name”
Delivering the message… How would that work here in LC 24?… • We need an address: 24.2.9.7 And right away we’re stuck. What does this mean? How do we find out?… • We need a DNS server, which we’ll use in reverse… going from “number” to “name”
The LC “DNS” server… Our hypothetical LC addresses, by analogy with IP addresses, are quadruples: LC (room) # . side of room . row # . seat # where left/right side (from front) is 1/2, row is from the front, and seat is from the aisle.
The LC “DNS” server… Our hypothetical LC addresses, by analogy with IP addresses, are quadruples: LC (room) #.side of room . row # . seat # where left/right side (from front) is 1/2, row is from the front, and seat is from the aisle. So where is 24.2.9.7?…
Now… • You try it….
Pieces of the message… • Splenda works • As well • As sugar • For packet • Switching
Each computer on the Internet is uniquely identified so that it can be addressed. It may have: • a name – for example, www.albany.edu But it must have: • an IP address – 169.226.1.110
The translation or resolution of the name to the address is done by a “domain name server” (DNS), the white pages of the Internet. There are thousands of DNSs around the world, and they all know that: 169.226.1.110 = www.albany.edu and vice versa.
The domain name has 2 parts – the host and top level domain (TLD). www.albany.edu albany = host (really University at Albany) .edu = top level domain= education
Domain categories Other top level domain categories in the U.S.: • .com – businesses • .edu – educational institutions • .gov – government agencies • .mil – military units • .net – networks • .org – non-profit organizations
The authority for domains… http://www.icann.org/ ICANN - Internet Corporation for Assigned Names and Numbers Newest TLDs: .mail – a site for anti-spam community .kid -??thoughts??
Next question… When was the Internet?
When was the Internet? 1961 – WOW!! Len Kleinrock (then at MIT) developed theory of “packet switching,” describing how data could behave on a highway where collisions were not only allowed but expected!!
When was the Internet? 1965 – Advanced Research Projects Agency (ARPA) in the Pentagon funded the first experimental connection between a computer at MIT and one in California… over a 1200 bps phone line.
When was the Internet? 1966-69 – ARPA contract awarded to an architectural consulting firm to design and build “ARPANET,” the direct ancestor of today’s Internet, with a starting configuration of four nodes!
When was the Internet? • 8/30/69UCLA • 10/1/69 SRI • 10/29/69 1st message, UCLA to SRI • 11/1/69 UCSB • 12/69 University of Utah
When was the Internet? By 1971, there were 23 “hosts” (computers) at 15 “nodes” in CA, UT, IL, MI, PA, & MA
When was the Internet? 1972 @ as connector for userid and address 1973 – 75% of all ARPANET traffic is email 1975 – first mailing list, MsgGroup, forerunner of listservs 4/12/79 –the “emoticon” :-) smiles
When was the Internet? 1980 – first accidental virus shuts down ARPANET 1984 – number of hosts breaks 1000, William Gibson coins “cyberspace” 1987 – number of hosts breaks 10,000 1989 – number of hosts breaks 100,000 1992 – number of hosts breaks 1,000,000
When was the Internet? 1990 – original ARPANET shut down 1991 – Tim Berners-Lee invents World Wide Web, CERN releases software 1993 – First browser 1994 – Arizona law firm sends first “spam,” first Pizza Hut takes orders online 1995 – Internet becomes commercial, AltaVista goes online in December