Ch 6 Application Layer
What is URL? Describe the parts of a typical web URL.
Character string describing location and access method to a resource on the Internet. First part is the protocol (http). Second part identifies host. Third part specifies port (optional). Fourth part specifies resource on host.
What is a hyperlink?
Link from one page to another.
Describe some changes in the patterns of Internet usage based on changes in the list of most popular websites globally.
2005 - information sites 2008 - social media 2010 - information sites
What are the functions of the application layer? How were the earliest application-layer protocols defined? What application do you spend the most time on?
Enables applications to use TCP and UDP. Primary function is to hide details of TCP and IP from end user applications. Earliest protocols were SMTP, FTP, Telnet. Likely use HTTP the most.
Why is the web gaining popularity as a marketing tool over traditional methods such as yellow pages?
Everyone on the internet all the time on computers and phones. Highly targeted marketing. Cost-effective.
What are the three most popular websites in the world today? What primary service does each site offer?
Google, Facebook, Youtube.
How is FTP different from HTTP?
HTTP - one channel of communication FTP - two channels, one for commands, one for data
What is presence in the context of IM?
Have a friends list and see status of other users.
Provide an overview of the structure of a web page.
Head - meta info Body - content
How has the web been most useful to you?
Looking at memes.
What is instant messaging? How is IM different from e-mail?
No server/mailbox.
What are some important differences between POP and IMAP?
POP - only one MUA can sync with server IMAP - multiple MUAs can sync with server using message IDs. Also allows for much more manipulation of server mailbox.
What is the role of POP/ IMAP in e-mail?
Protocols used by MUAs to manipulate email from MTAs.
Describe the differences between pull and push forms of communication, using the web and e-mail as examples.
Pull - receiver decides what info he/she wants from a resource (browsing a website). Push - sender decides what info and what receivers to target (sending an email).
Using examples from your own life, describe some advantages of e-mail as a communication medium compared to your other choices (such as cell phones, meetings).
Respond at any time, records conversation thread, can search inbox.
In what ways do you use e-mail in your daily life? When do you prefer to use e-mail over the postal system? When do you prefer the postal system over e-mail?
Sending memes.
What is the role of SMTP in e-mail?
Simple Mail Transfer Protocol. Transfer email between MTAs.
What are some potential disadvantages with e-mail as a communication medium? Can you describe some occasions when you have run into these disadvantages of e-mail?
Spam.
What is HTML?
The markup language used for making websites.
What is an inlink? What information about a web page can be inferred from inlinks to the page?
Tracks external hyperlinks linking to your page.
What is FTP?
Transfer files from one computer to another.
What is a killer application?
Very popular application.