Transcript What happens when you request a Web page?

Retrieving a Web page
IT skills:
IT concepts: Web client (browser), Web server,
network connection, URL, mobile client, peer-topeer application
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Where does this topic fit?
• Internet concepts
– Applications
– Technology
– Implications
• Internet skills
– Application development
– Content creation
– User skills
Client and server
Client
Server
Uniform resource locator (URL)
What happens next?
Establish a temporary connection
Client
Server
Request the page
Request
Client
Server
Send the page to the client
Request
Client
page
Server
Client displays the page
Request
Client
page
Server
Drop the connection
Request
Client
page
Server
Data flow
Client
Web
client
program
Server
Request
Web
server
program
Page
Memory
Requested
page
Display
Memory
The Internet
Requested
page
Storage
What if the requested page is not found?
Pages with links
1. Get first page
Client
Server 1
Server 2
Mobile Web clients
Memory in peer-to-peer applications
Operating system
Client program
Server program
Summary: retrieving a Web page
request
page
Client
1.
2.
3.
4.
5.
Server
Establish a temporary connection between the client and server
Client sends the request to the server
Server returns the requested page or an error message
Client displays whatever the server returns
Disconnect
Questions
request
page
Client
Server
Without looking back, do you recall the steps in retrieving a
Web page?
1.
2.
3.
4.
5.
1. Does a URL show both the computer to connect to and the name
of the file to retrieve or just the file name? Explain your answer.
2. What happens if the user accidentally misspells the URL?
3. Can one server be handling requests from more than one client
at a time? Explain your answer.
4. Do the terms client and server refer to hardware or software?
Explain your answer.