internet - waseda university7 what’s the internet: “nuts and bolts” view millions of connected...
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Introduction of the Internet
System of Internet
What can be done using Internet
Merit of Internet
Technologies in the Internet
Protocol
Routing
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Stand Alone
Computers are used to be standing alone.
X
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Connect two machines
Sharing the information between two machines.
Copying files etc.
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Local Area Network (LAN)
Connecting machines.
Hub
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The Internet
Connecting LANs globally.
Company A
University B
Agency CLab. D
Provider E
domain
domain
domain
domain
domain
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What’s the Internet: “nuts and bolts” view
millions of connected computing devices: hosts, end-systemspc’s workstations, serversPDA’s phones, toasters
running network apps
communication linksfiber, copper, radio, satellite
routers: forward packets (chunks) of data thru network
local ISP
companynetwork
regional ISP
router workstationserver
mobile
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DomainThe name of organization connected to the internet.
waseda.jp!: Waseda University
waseda.ac.jp
ntt.co.jp!! : NTT
kantei.go.jp! : Japanese government
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Structure of Domain Name
Domain name is consisted by the name, attributes and nationality of organization.
http://www.internic.net/faqs/authoritative-dns.htmlWhat is waseda.ac.jp?
“waseda” is the name of organization, “ac” represents academia, and “jp” means japan.
Nationalityca:Canada�uk:United Kingdom�fr:France�au:Australia etc.
Attributesco:company�go:government�ne:internet provider
NameYou can name it!
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Address
You need address to send a message to the computer on the receiver side.
Use IP address or domain name. IP address
Handled by computers. 164.125.25.10Consisted by network number and computer number.
Domain nametractable for human beingcomputer!-----!aoni.waseda.jpmail!! [email protected]!! -----!www.waseda.ac.jp
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Example of address
NTT
Waseda
Fukushima government
waseda.ac.jp
ntt.co.jp
pref.fukushima.jp
router
den.ntt.co.jp(210.173.163.201)
aoni.waseda.jp
(202.225.207.18)
www.abc.pref.fukushima.jp
URL
mail address
Domain name
Domain name
Domain name address
address
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What you can do using internet
Browsing（World Wide Web: WWW）E-mailFTP: file transferBBS (electric bulletin board)File SharingBlogMusic DownloadChatMultimedia player (Video, music）
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WWWSystem to make and look homepages.
Using hyper link.
Browsers
Netscape Navigator
Internet Explorer
Making Home pages
Use HTML (Hyper Text Markup Language)
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A Simple HTML Example
<html>! <head> ! <TITLE> A Simple HTML Example </TITLE>! </head> ! <body> ! !<H1> HTML is Easy To Learn </H1> ! !<P>Welcome to the world of HTML. This is the first paragraph. While short it is still a paragraph!</P> ! !<P>And this is the second paragraph.</P> ! !<P>This is an example of link.! !! <A HREF="http://www.f.waseda.jp/toyoizumi>Click it!</A> ! !</P> ! !<P>This is also an example of inline image. Can you find where the original is?<BR>! !! <IMG SRC=http://www.waseda.jp/sils/img/ph_title.jpg>! !</P> </body> </html>
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Result of the Simple HTML Example
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E-mail on Waseda-net Portal
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FTPTransfer (get or put) files via network. This is the most basic tool for uploading your file on the internet.
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Upload Your HTML
1. Find your ftp server of waseda net.
ftp.aoni.waseda.jp
4. Use a ftp tool named ffftp to connect the server.
5. Upload the file onto the server.
6. Check your first home page at
www.yyyy.waseda.jp/xxx
BBS and Community
Chat
http://www.microsoft.com/japan/mac/column/contents/messenger.asp
File Sharing
Blog
http://blog.livedoor.jp/takapon_ceo/
Music Store
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Multimedia Player
Play movies or music on the internet.
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Advantages of internet
You can access global information without going there.You can communicate with people all over the world.You can do business world wide. You don’t have to consider the national border. Distance education and distance medical care.Reduced cost of transportation.
How P2P works
http://www.ascii.co.jp/bookmart/pdf/47561/4756145485.pdf
P2P network are supposed to work without central administraion.
Music Downloading
Pick one of your favorite pop musics you have.
Write it down on a piece of paper.
For example : Pussycat dolls, Stickwitu
Suppose you are a PC with the music.
Commercial Model- iTunes Music Store Type
download
query
Server Client ModelNapster type
You should register the music to the central server.
register
download
query
P2P Model- Winny, eDonkey type
No central server. The information are dynamically spread in the network.
Search and Transfer Music
Pick one of the pop music you would like to search.
Ask your neighbor to search.
If you are asked by neighbor, but you don’t have the music, ask your next neighbor again.
If you have the file, send the music (the music paper) to the one who asked for it.
P2P NetworkEventually, you could find the file on P2P network.
query
query
query
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Internet Technology
Protocol
Routing
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What is Protocol?Protocol is the rule for communication.
As you need to follow the traffic rule when you drive a car, you need to follow the rule during communication.
Internet employs a protocol called TCP/IP is mainly used.
IP ! Rule for controlling path along internet.
TCP !Rule for transfer data without error.
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Hierarchy
Application
Presentation
Session
Transport
Network
Data link
Physical
Data unit Data unit
Addheader
Removeheader
Communication link
Hierarchical Protcol
Application
Presentation
Session
Transport
Network
Data link
Physical
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What is Routing
You need to decide a path from source to destination in order to transmit your data.
A Ltd.
B University
C officerouter router
router
destination Port #C office 1
B university 2
Routing table
1
2
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Variation of routing
Routing methods
Static routing
You don’t change the route which is decided at the beginning.
Dynamic routing
Depending on the network condition, the optimal route is automatically found and configured.
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Examples of Your Assignments
1. Blog and RSS2. Instant Messaging3. Podcasting4. xDSL/FTTH5. Hot Spot/WiFi/WiMax6. XML7. Auction site8. Wiki/Wikipedia9. Social Networking Site10. Internet telephone11. Waseda-net Portal12. Internet on cell-phone13. Web 2.0