DESC 384: Business Data Communications
Homework Assignments

Exercise 5-5 from Chapter 5 (page 187). Answer both (a) and (b) in detail, but (c) only in general. Note that (c) is not the same question as (a) or (b).

Note the following clarification:

• "Configuration tables" refers to the kind of information found in figure 5.13. Other than this information, the client computer does not know any addresses.

Suppose you have three friends who share an apartment in downtown Montréal, and each of them has a computer. Your friends want to get Internet access that all three of them can share. Assuming that they have access to a regular phone line, DSL, and cable TV, what would you recommend if your friends want to spend:

• no more than $10 per month per person, and maximum of $50 per person for setup?
• no more than $20 per month per person, and maximum of $100 per person for setup?
• any price for the highest possible speed for residential customers?

All costs must include taxes and any "hidden" fees. Be sure to list the pros and cons of each option you recommend, apart from cost. For each recommendation, specify real services available in Montreal, and calculate current prices for setup and monthly fees. "Setup" includes any setup fees assessed by the provider, plus the cost of routers, switches, or modems, if necessary for your selected option.

Two more questions:

• If you have Internet access at home, what service do you use?
• After this exercise, are you thinking of switching to something else?

Find a news story about one of the following network-based security problems that occurred this year (2009) anywhere in the world: hacker/cracker, network-based fraud, virus/worm/trojan horse, or DoS. Do the following:

1. Briefly but clearly summarize the security problem.
2. Who were the victims? Were the perpetrators identified? If so, who were they?
3. Approximately how much money and time did this problem cost the victims?
4. What security hole was exploited? ("Security hole" means an oversight, breakdown or laxity in security that was taken advantage of.) How can this problem be resolved?
5. What risk is there for similar incidents in the future, both for the current victims and regarding other potential victims?