1.4: The magic of packet switching
The dance of the electrons
When you type a Uniform Resource Locator into a browser, the following steps occur:
- The browser breaks the URL into three parts:
- The protocol (http)
- The domain and host name (www.stthomas.edu)
- The path and file name (cojo258/index.html)
- The browser communicates with a name server to translate the domain and host name, www.stthomas.edu, into an IP address in hexidecimal numbers.
- The browser then forms a connection to the Web server at that IP address.
- After the HTTP protocol, the browser sends a GET request to the server, asking for the file http://courseweb.stthomas.edu/mjodonnell/cojo258 (with index.html assumed to be the page name).
- The server sends the HTML text for the index.html Web page to the browser.
- The browser reads the HTML tags and formats the page onto your screen.
All of this happens through the magic of packet switching. Large files are broken up into packets containing metadata that allows the file to be reassembled at the receiving end. The packets might take different routes over the distributed network.