Design Project Two: Frequently-Asked Questions

Last updated: $Date: 2008-04-27 20:49:16 -0400 (Sun, 27 Apr 2008) $

Q: Do I really need to stay within 5,000 words?

A: Yes. We expect you to adhere to the word limit. That said, we're not going to penalize you for being just a few words over the limit -- we're mostly concerned with the quality of your report. If your report contains 5,000 + X words, and you're worried whether X counts as "just a few," you should probably cut some words. Remember to print the word count at the end of your final report.

Q: Do the figure captions count against the word limit?

A: Yes. Don't skimp on captions to lower your word count however; appropriate captions are important for clarity.

Q: Can the MIT host acquire multiple IP addresses?

A: No. Your server at MIT has only a single interface, and will have a single IP address. You may find you need to implement Network Address Translation (NATing) to provide support for multiple clients via this single IP address.

Q: Do clients have "real" IP addresses, or does each access points assign a different private IP address to each client?

A: When a single client associates to many APs, each AP will assign an address from its private space, corresponding to that association. That is, a single client that is associated to two APs will be assigned two IP addresses, one assigned by each AP, and both of these will be private.

Note that since there is no coordination between APs, these two addresses could even be the same! If routing in your system were based purely on the routing table, this would be a problem; however, since your software will control the routing of traffic to the appropriate AP by specifying a virtual interface, it can still work.

You may assume that each client participating in Stripe@Home has been assigned an ID number that is unique among all Stripe@Home clients. This ID can be used to distinguish different clients.

You may also assume that the client initially associates to one of the APs in the usual way. Any traffic that you choose not to intercept will go to that AP and be sent on as it would normally. The traffic that you do intercept should be forwarded through your system via specific virtual interfaces.

Q: So the client initially associates to a single access point, and any traffic that is not intercepted by our shim gets sent directly over this link. What happens if this access point goes down? Do we need to reassociate to another access point while trying to maintain the same IP address?

A: For the purposes of this project, assume that the "default" access point (the one you associate with first, see previous FAQ entry) never goes down. This is not a completely unreasonable assumption, since this will be the access point that you own and administer in your apartment. You do not need to worry about scenarios where the connection with this access point breaks, but you should assume that any of the other access points may fail or go out of range at any time.

Questions or comments regarding 6.033? Send e-mail to the 6.033 staff at or to the 6.033 TAs at

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