and the questions are...

1. (1.5 points) Refer to the list of e-commerce models we discussed in the first two classes (see lecture #1 notes, jan 26). Pick three e-commerce models and for each one, find an example URL. Explain how your example fits the model. You CANNOT use the examples discussed in class (ebay and amazon).

2. (1.5 points) In class, we discussed domain names and IP addresses. We mentioned that the URL of the CIS department web server www.sci.brooklyn.cuny.edu. It's IP address is 146.245.250.131.
   Go to the http://www.dnsstuff.com/ web site, where you can look up IP addresses of domain names (and vice versa). There are many things you can do on this web site. Find the column labeled Hostname Tests and the section labeled DNS lookup. Enter www.sci.brooklyn.cuny.edu in the text field and click on Lookup (don't worry about the dropdown menu to the rigth of the text field -- you can leave that on the default value (A)).
   You'll see a results page, which first shows how the domain name search was perfomed (i.e., through a series of domain name servers), followed by a table containing the resolution and the IP address of the host name that you entered, in this case 146.245.250.131. Click on the IP address and you get even more information!

   Your assignment is to look up 3 other sites and report the domain names and IP addresses. At least one should be another Brooklyn College web site. As we discussed in class, the IP address fields are divided into domain, subnet and host. Be sure to include in your homework the names and IP addresses of the three sites you used, and identify the domain, subnet and host for each IP address.

3. (2 points) In class, we discussed connection-oriented and connectionless networks. Describe each and explain the differences between them. Give an example of an internet protocol employed by each.