on Networking - TSHS - Tahoma Senior High School

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					FIT100
FIT100




         2
                    Naming Computers I
FIT100
 People name computers by a domain
   name -- a hierarchical scheme that
   groups like computers
        .edu All educational computers
        .washington.edu All computers at UW
           dante.washington.edu A UW computer
        .ischool.washington.edu iSchool computers
        .cs.washington.edu CSE computers
Peers
           june.cs.washington.edu A CSE computer


  Domains begin with a “dot” and get “larger” going right 3
FIT100
• What is the Tahoma naming
  scheme?
    Look at our website URL
    ComputerPropertiesComputer
     Name




                                    4
FIT100




         5
                Naming Computers II
FIT100
 Computers are named by IP address,
   four numbers in the range 0-255
      cse.washington.edu: 128.95.1.4
      ischool.washington.edu: 128.208.100.150
    Remembering IP addresses would be
     brutal for humans, so we use domains
    Computers find the IP address for a
     domain name from the Domain Name
     System -- an IP address-book computer

 A computer needs to know IP address of DNS server!   6
FIT100
• http://whatismyip.com/




                           7
FIT100




         8
                                      Domains
FIT100
.edu .com .mil .gov .org .net domains
  are “top level domains” for the US
    Recently, new TLD names added
    Each country has a top level domain
     name: .ca (Canada), .es (Spain), .de
     (Germany), .au (Australia), .at (Austria),
     .us
      The FIT book contains the complete list
                                                9
FIT100




         10
                   Logical vs Physical
FIT100
There are 2 ways to view the Internet
     • Humans see a hierarchy of domains
       relating computers -- logical network
     • Computers see groups of four number IP
       addresses -- physical network
     • Both are ideal for the “users” needs
• The Domain Name System (DNS)
  relates the logical network to the
  physical network by translating
  domains to IP addresses                       11
FIT100




         12
               Client/Server Structure
FIT100
The Internet computers rely on the
  client/server protocol: servers
  provide services, clients use them
      • Sample servers: email server, web server, ...
      • UW servers: dante, courses, www, student,…
      • Frequently, a “server” is actually many
        computers acting as one, e.g. dante is a
        group of more than 50 servers
   Protocol: Client packages a request, and sends it to
   a server; Server does the service and sends a reply13
FIT100




         14
                     World Wide Web
FIT100
 World Wide Web is the collection of
   servers (subset of Internet computers)
   & the information they give access to
     • Clearly, WWW  Internet
     • The “server” is the web site computer and
       the “client” is the surfer’s browser
     • Many Web server’s domain names begin
       with www by tradition, but any name is OK
     • Often multiple server names map to the
       same site: MoMA.org and www.MoMA.org
                                               15
FIT100




         16
              Client/Server Interaction
FIT100
For Web pages, the client requests a
  page, the server returns it: there’s no
  connection, just two transmissions
           Server                               Client
  Server            Server             Client            Client
                             request
 Server    Client             reply             Server    Client

  Server            Server             Client            Client
           Server                               Client


 Servers serve many clients; clients visit many servers 17
FIT100




         18
                     Dissecting a URL
FIT100
Web addresses are URLs, Uniform
 Resource Locator, IP address + path
     •URLs are often redirected to other
      places: http://mshess.com
     goes to
      http://tshs.tahomasd.us/sites/hess/



                                            19
                                     Dissecting a URL
FIT100
 Web addresses are URLs, Uniform
  Resource Locator, IP address + path
           • URLs are often redirected to other places;
             e.g. http://mshess.com goes to
                 http://tshs.tahomasd.us/sites/hess/index.html

protocol          = http://
Web server        = tshs
domain            = tahomasd.us
path              = sites/hess/       directories (folders)
file              = index
file extension    = .html                      hypertext markup language
                                                                           20
FIT100




         21
                  WWW vs. Internet
FIT100
• WWW is the part of the Internet that
  uses the http protocol
    Web servers and the Web pages they
     store and serve
    Web browsers are the clients
• Internet is all the wires, routers,
  gateways, servers—all using TCP/IP
  to transfer packets
                                          22
         Your UW Storage Space
FIT100




                             23
         Your Web Files
FIT100




                      24
FIT100




         25
                                   HTTP

FIT100
• Hypertext Transfer Protocol
   Understands how to interpret URLs
    •Uniform Resource Locators
   Divides URL into server and pathname
                                                          HTTP

FIT100




 http://faculty.washington.edu/daclem/LIS549sp08/index.html
                                                             HTTP

  FIT100




    http://faculty.washington.edu/daclem/LIS549sp08/index.html

PROTOCOL
(Web)
                                                             HTTP

  FIT100




    http://faculty.washington.edu/daclem/LIS549sp08/index.html

PROTOCOL SERVER
                                                             HTTP

  FIT100

                 Read Right to Left


    http://faculty.washington.edu/daclem/LIS549sp08/index.html

PROTOCOL SERVER
                                                             HTTP

  FIT100

                 Read Right to Left


    http://faculty.washington.edu/daclem/LIS549sp08/index.html

PROTOCOL SERVER

           1. Domain: edu
                                                             HTTP

  FIT100

                 Read Right to Left


    http://faculty.washington.edu/daclem/LIS549sp08/index.html

PROTOCOL SERVER

           1. Domain: edu
           2. Subdomain: washington
                                                             HTTP

  FIT100

                 Read Right to Left


    http://faculty.washington.edu/daclem/LIS549sp08/index.html

PROTOCOL SERVER

           1. Domain: edu
           2. Subdomain: washington

           3. Server: faculty
                                                             HTTP

  FIT100




    http://faculty.washington.edu/daclem/LIS549sp08/index.html

PROTOCOL SERVER                         PATHNAME

           1. Domain: edu
           2. Subdomain: washington

           3. Server: faculty
                                                             HTTP

  FIT100

                                        Read Left to Right


    http://faculty.washington.edu/daclem/LIS549sp08/index.html

PROTOCOL SERVER                         PATHNAME

           1. Domain: edu
           2. Subdomain: washington

           3. Server: faculty
                                                             HTTP

  FIT100

                                        Read Left to Right


    http://faculty.washington.edu/daclem/LIS549sp08/index.html

PROTOCOL SERVER                         PATHNAME

           1. Domain: edu               4. Account: daclem
           2. Subdomain: washington

           3. Server: faculty
                                                             HTTP

  FIT100

                                        Read Left to Right


    http://faculty.washington.edu/daclem/LIS549sp08/index.html

PROTOCOL SERVER                         PATHNAME

           1. Domain: edu               4. Account: daclem
           2. Subdomain: washington 5. Folder: LIS549sp08

           3. Server: faculty
                                                              HTTP

  FIT100

                                        Read Left to Right


    http://faculty.washington.edu/daclem/LIS549sp08/index.html

PROTOCOL SERVER                         PATHNAME

           1. Domain: edu               4. Account: daclem
           2. Subdomain: washington 5. Folder: LIS549sp08

           3. Server: faculty           6. File: index.html
                                                              HTTP

  FIT100

                                        Read Left to Right


    http://faculty.washington.edu/daclem/LIS549sp08/index.html

PROTOCOL SERVER                         PATHNAME

           1. Domain: edu               4. Account: daclem
           2. Subdomain: washington 5. Folder: LIS549sp08

           3. Server: faculty           6. File: index.html
             Finding Server and Pathname
FIT100
         http://courses.washington.edu/wtcampus/autumn/


         •    Finding the Server:
               1. Domain: edu
               2. Subdomain: Washington
               3. Server: courses
         •    Finding the Pathname:
               4. Account: wtcampus
               5. Directory: autumn
                   whois Information
FIT100
• You can use:
  http://whois.domaintools.com/
  to find out who owns a domain and
  where the company is located, etc.

For example, let’s search:
   IP address: 17.112.152.32
                                   41
                      Activity
FIT100
• Dissecting URLs….




                             42
FIT100




         43
                                    Networks
FIT100
• Servers
    Your own home computer
     • If you’re sharing files with someone else
    A single computer in a UW department
    A cluster of many computers (Dante)
     • Server software distributes the “load”
       among the servers
     • Server “farm” is across campus

                                                   44
FIT100




         45
         SSH Secure File Transfer (SFTP)
FIT100
• Copy files between two computers
• Use it at home or anywhere
                   Why use SFTP?
FIT100
  Advantages:
  • Secure, encrypted transfers
  • Remote access from anywhere
  • Network space (storage/backup)
         SFTP Client/Server Model
                              Local CPU


FIT100
         Keyboard



                    Input                  Output
                                                      Monitor

          Mouse




              Local storage
              space

                              Hard Drive
                                                                        Remote CPU
                                                                dante.u.washington.edu



                                           SFTP
                                           UPLOAD
                                           DOWNLOAD


                                            Your UW account directory
                                               UW NetID:________            Hard Drive
                                              Password :_________
                      SFTP Interface
FIT100
     Local Computer      Remote Server

				
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