what is the difference between Web and internet
web is Information shared over the internet using the Hypertext Transfer Protocol (HTTP),
internet:International network of connected computers
To reach 50 million people:
Radio took … years
TV took … years
Internet took just … years
Radio took 38 years
TV took 13 years
Internet took just 4 years
Problems created by internet own success
More computers are linked (1984 – 1000 hosts)
Large volume of traffic (success of e-mail)
DNS (Domain Name System)
Distributed and scalable mechanism for resolving host names into IP addresses
what is networking
When two or more devices are connected for data sharing or resources, we call it networking
difference between networking and internetworking
- In networking (LAN) all devices are compatible with each other
- It may or may not be the case in internetworkingo- Differences in hardware and software make
systems incompatible
The internet exists today because of a suite of interrelated communications protocols
true of false
true
……. and …… use TCP/IP protocols to connect to the internet
Web browsers and servers
TCP/IP stand for
Stands for Transmission Control Protocol/Internet Protocol
IP takes care of the communication with ….
TCP takes care of the communication between ….
other computers
between your application software (i.e. your browser) and your network software
Domain names and IP addresses are not permanently attached
True or false
true
You can’t own a domain name and move it from one host to another
True or false
false
Two computers in a network or internetwork can have identical names
True or false
false
Browser
The software that requests resources (data or documents) from the web server.
The resource format is usually HTML (Hyper Text Markup Language) but can also be PDF, image, etc.
The program in the browser that interprets HTML/CSS/JavaScript is called ……
the rendering engine
URL stands for
Uniform Resource Locator
How do web pages work?
- You type in a URL, which is the address of the HTML file on the internet.
- The browser asks the web server that hosts the document to send that document.
- The web server responds to the browser with HTML file that was requested.
- The browser reads the HTML, sees the embedded resources and asks the server for those as well.
- The web page is loaded when all the resources are fetched and displayed.
….. is a program running on a computer that delivers web pages in response to requests.
web server
html Describes the ……. and ……. of a web page
content and structure
error 503
Service Unavailable: This is a catch-all error message for a variety of problems, but all of them mean that the website is incapable of contact by your browser
How Cookies Work
- The first time a Web page is requested, no cookie is included, so the server creates a cookie and returns it
- For later visits to the same website, the request will contain the cookie generated at the previous visit
- The server updates the cookie (if needed) and returns it with the page
- This way the server ”remembers” the client from one visit to the next
Cookie Format
Name: name of cookie
Value: contents of cookie – can be an array of values
Domain: domain of the server that is to receive the cookie
Expires: When cookie will expire
Path: Path in server from which cookie can be sent
Secure: Does cookie require secure server using https
Default is no
Cookie Storage
-Temporary cookies (session cookies)
o-stored only for your current browsing session and is deleted from your computer when you close the browser
-Persistent cookies
o-stored as a file on your computer, and it remains even when you close the browser
o-can be read by the Web site that created it when you visit that site again
Cookie Originator
-First-party cookie
o-originates on or is sent to the Web site you are currently viewing
o-these cookies are commonly used to store information, such as your preferences when visiting that site
-Third-party cookie
o-originates on or is sent to a Web site different from the one you are currently viewing
o-common use for this type of cookie is to track your Web page use for advertising or other marketing purposes
