Your SlideShare is downloading. ×
  • Like
Networking And Internet
Upcoming SlideShare
Loading in...5
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×

Now you can save presentations on your phone or tablet

Available for both IPhone and Android

Text the download link to your phone

Standard text messaging rates apply

Networking And Internet

  • 441 views
Published

internet

internet

Published in Technology
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Be the first to comment
    Be the first to like this
No Downloads

Views

Total Views
441
On SlideShare
0
From Embeds
0
Number of Embeds
0

Actions

Shares
Downloads
26
Comments
0
Likes
0

Embeds 0

No embeds

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
    No notes for slide

Transcript

  • 1. Networking and Internet Tian-Li Yu [email_address] Department of Electrical Engineering National Taiwan University
  • 2. Network classifications
    • Scope
      • LAN: local area network
      • MAN: metropolitan area network
      • WAN: wide area network
    • Ownership
      • Closed
      • Open
    • Topology
  • 3. Network topology Ring Bus Star hub
  • 4. Protocols
    • Token ring
      • Popular in ring topology.
      • Token and messages are passed in one direction.
      • Only the machine that gets the token can transmit its own message.
    • CSMA/CD
      • Carrier sense, multiple access with collision detection.
      • Popular in bus topology (Ethernet).
      • Broadcasting.
      • When collision, both machines wait for a brief random time before trying again.
  • 5. Dilbert on token ring Dilbert, Scott Adams
  • 6. Connecting compatible networks
    • Repeater
      • Simply passing through messages.
      • Connecting two compatible networks.
    • Bridge
      • Only passing those messages addressed to the other side.
      • Connecting two compatible networks more efficiently.
    • Switch
      • A bridge with multiple connections.
      • Connecting several compatible networks more efficiently.
  • 7. Repeater, bridge, and switch Textbook, Figure 4.4
  • 8. Connecting incompatible networks
    • Router
      • Building a network of networks, known as an internet .
    Textbook, Figure 4.5
  • 9. Interprocess communication
    • Server-client
      • One server, several clients.
      • Clients initiate communications by sending requests.
      • Server serves.
    • P2P (peer-to-peer)
      • Two processes communicating as equals.
      • The most popular distribution mode nowadays.
  • 10. Interprocess communication (contd.) Textbook, Figure 4.6
  • 11. Distributed systems
    • Infrastructure can be provided by standardized toolkits.
      • Enterprise Java Beans by Sun Microsytems
      • .NET framework by Microsoft
  • 12. The I nternet
    • The most notable example of an internet is the Internet.
    • Original goal was to prevent disruptions caused by local disaster.
    • Now it’s a commercial undertaking.
  • 13. Internet architecture
    • Domain
      • a network or an internet controlled by one single authority.
    • ICANN (Internet corporation for assigned names and numbers)
      • Oversee the registration of domains.
      • Registrar
    • Gateway
      • A router that connects a domain to the rest of the Internet (the Internet cloud).
  • 14. Domains, gateway, and the Internet Textbook, Figure 4.7
  • 15. Connecting to the Internet
    • ISP (Internet service provider)
      • Allow customers to connect their domain to the ISP’s equipment or join the domain already established by the ISP.
    • Different means
      • Telephone (dial-up)
      • Cable
      • DSL
      • Wireless
  • 16. IP addresses
    • IP (Internet protocol) addresses
      • 32 bit in IPv4
      • 128 in IPv6
    • Network identifier (by ICANN)
    • Host address (domain administrator)
    • Dotted decimal
      • 140.112.18.33
  • 17. Host names
    • Mnemonic address made up of two parts
    • Domain name
      • Assigned by a registrar
      • edu.tw
      • Top-level domain
        • By usage: .edu = education
        • By country: .tw = Taiwan
    • Subdomains and individual host names
      • Assigned by domain owner
      • www.ee.ntu .edu.tw
    • Name server & domain name server (DNS)
      • www.ee.ntu.edu.tw  140.112.18.33
  • 18. Internet applications
    • VoIP (voice over Internet protocol)
    • email (electronic mail)
    • FTP (file transfer protocol)
    • telnet & ssh (secure shell)
    • p2p: bittorrent, edonkey, emule…
  • 19. World wide web
    • www, w3, web
    • hypertext, hyperlink, hypermedia.
    • Web page: hypertext document
    • Website: a collection of closely related web pages.
  • 20. Browsers
    • Presenting the web pages downloaded from the Internet.
    • HTTP (hypertext transfer protocol)
    • URL (uniform resource locator)
    Textbook, Figure 4.8
  • 21. Hypertext markup language Textbook, Figure 4.10
  • 22. eXtensible markup language
    • XML
    • Standard style to represent data as text.
    • Restricted mapping each opening to each ending.
    • <x property=“yyy”> …… </x>
    • XHTML
      • HTML that follows XML format.
    <name code=“ISO-8859-1”> Tian-Li Yu </name> <name code=“Big5”> 于天立 </name> <education> <BS> NTUEE, 1997</BS> <MS> UIUCCS, 2003 </MS> <PhD> UIUCCS, 2006 </PhD> </education>
  • 23. Client-side & server-side
    • Client-side
      • Java applets
      • Java scripts
      • Flash
    • Server-side
      • CGI
      • Servlets (jsp, asp)
      • PHP (Personal Home Page, PHP Hypertext Processor)
  • 24. Internet protocol
    • Layers
      • Application: constructs message with address
      • Transport: chops message into packets
      • Network: handles routing through the Internet
      • Link: handles actual transmission of packets
    • Port (not the I/O port)
  • 25. Layers Textbook Figure 4.14
  • 26. TCP/IP suite
    • TCP and IP are two protocols, TCP/IP refers to a collection of protocols more than just TCP and IP.
    • TCP (transmission control protocol)
    • UDP (user datagram protocol)
      • No notification before sending message, no retransmission service, no acknowledge of receiving message.
    • TCP: more reliable, less efficient
    • UDP: more efficient, less reliable
  • 27. Security
    • Attacks
      • Malware (malicious software)
        • Virus, worm, Trojan horse, spyware, phishing)
      • Denial of service
      • Spam
    • Protections
      • Firewall
      • Spam filter
      • Proxy
      • Antivirus, antispyware
  • 28. Encryption
    • sftp (ftps as in the textbook) , https, ssh, ssl
    • Public/private keys
      • Public key  encryption
      • Private key  decryption
    Textbook Figure 4.16
  • 29. Public/private key issues
    • Certificate authority
      • Ensure the public key is given by the trusted one.
    • Authentication
      • Make sure the author of a message is, in fact, the party it claims to be.
      • Use private key to encrypt; public key to decrypt.
  • 30. Exercises
    • Chapter 4: 1, 7, 8, 12, 20, 26, 27, 35, 37, 39, 40, 43, 46.