6.1 The Internet is a network of autonomous systems. 6.1.1 Explain the abstractions in the Internet and how the Internet functions. [P3] Exclusion Statement (LO 6.1.1): Specific devices used to implement the abstractions in the Internet are beyond the scope of this course and the AP Exam.
6.1.1A The Internet connects devices and networks all over the world.
6.1.1C Devices and networks that make up the Internet are connected and communicate using addresses and protocols.
6.1.1D The Internet and the systems built on it facilitate collaboration.
The Internet is a network of independent but connected devices all over the world. People talk as if "the Internet" and "the World Wide Web" are the same thing, but they are not. The World Wide Web is the collection of interlinked website documents (such as HTML files) that you can view with a web browser by typing addresses like http://bjc.berkeley.edu/website/privacy.html.
Most web pages are written with HTML (hypertext markup language) and interpreted by your browser using HTTP (hypertext transfer protocol).
A URL, or Uniform Resource Locator, is an address for accessing specific web data located on a server (a computer hosting data for others to access). URLs can be broken into three parts:
The protocol is not visible in the location bar of some browsers (like Chrome).
protocol—the standard for communication between browsers and servers (usually "http" or "https")
domain name—the name of the server that hosts the data
path—the location of the data in a hierarchy of folders on the server
For example, the URL shown above tells a browser to use the http protocol to access the bjc.berkeley.edu server and then go to the website folder and open the privacy.html file.
But the Internet is more general than the World Wide Web. It also supports email, file transfers, mobile apps, texting (a.k.a. SMS or Short Message Service), and many other ways that computers communicate behind the scenes.
The Internet is a massive network of computers that communicate, facilitating communication around the globe. They do this primarily by using a pair of protocols (standards for communication) that you will learn more about in another lab:
IP (Internet Protocol), an addressing system that finds paths to distant computers
TCP (Transmission Control Protocol), a reliable transmission system that sends and tracks binary sequences of data that are split into small packets sent separately
The algorithms that ensure data reach their destinations must continue to work even as the Internet grows. So, the Internet was designed to be:
Redundant: There are multiple pathways among the physical connections of the Internet to create redundancy. Even if one pathway is unavailable, there is still another way to transmit a message from sender to receiver (as shown right).
Hierarchical: There are two hierarchical Internet addressing systems, domain names (as shown below) and IP addresses. These address hierarchies works much like the postal system, which locates people first by state, then city, then street, then house number, then apartment, and then finally person.
The next two pages of this lab are about these two ideas.
Describe the parts of this URL for the Snap! logo:
