Answers to Fall 08 midterm 1. Why won't IETF develop web voting standards? The IETF's charter is to make the Internet better and to make it work. It works internationally, developing protocols and standards that help make the internet work. Electronic voting is not an international standard since voting rules differ drastically across countries/nations. The IETF doesn't report to governments nor is it political, so the chances it could develop standards that would be tied to the political/government entities in countries is unlikely. 2. Routers and DNS: Routers help find routes on the internet, they help packets get from one place to another and are based on IP addresses. DNS resolves domain names into IP addresses -- it's not about routing, but about addressing. If you type www.realestate.com into your browser, the DNS system from your own local cache, to your IPService Provider's DNS to broader DNS servers eventually helps find the IP address for www.realestate.com: 12.21.231.30 -- this address is used by the Internet to find the web pages/website that corresponds to realestate.com, and routers return that page/site to your machine. 3. Better granularity and less waste, i.e., if you need 500 addresses you could get 512 in the new system (2^9) rather than the wasteful 65,536 (2^16). Not all addresses are used because of this "waste", so allocating all powers of 2 rather than just three makes sense. Powers of 2 are used because data is stored in computers in terms of ones and zeros using binary/base-two, so powers of two determine how many different values there are for various numbers of bits, e.g., a 32-bit address yields 2^32 different values. 4. Unlikely that the DNS system will blow up. First, the 13 servers are replicated/mirrored -- the data for each root server is stored identically across many machines, not just one for each root. Furthermore, most DNS queries don't reach the root server, they're answered by local ISP caches/servers. 5. Both Wikipedia and predication markets use "crowdsourcing", leveraging the collective wisdom of crowds. Wikipedia has a "right" answer in the sense of reporting on established facts, not opinions. Predication markets are meant to predict what will happen, not report historically on what has happened. 6. The Internet facilitates rapid exchange of ideas and information, making it possible for email and blogs (for example) to spread truth and perceived truth. Communication among like-minded/similar-thinking people can happen quickly Similarly, misinformation can be combatted using the same speed of dissemination. However, it's often difficult to change perceptions even in the face of truth -- that's because of people, not because of the Interne. Changing opinions isn't always possible in the face of facts. 7. The 0's and 1's making up the mp3 haven't changed, so if the browser/player looks at the data rather than the name of the file, it will be able to play the audio file. Most data files store the kind of file in the 0's and 1's -- the name of the file is a convenience, but the real data is in the 0's and 1's. 8. Depends on you to answer. 9. Skype leverages the power of laptop/desktop computers which can encrypt easily, and for which encryption software is widely available and often already on computers or easily downloaded. Cell phones use processors that aren't as powerful, so doing the encryption/decryption is hard/tricky. Also the demand for encryption on computers is significant -- not so much for phones but for secure transactions. People store sensitive data on their computers, not so much on cell phones. Supply and demand may affect the price too -- if there was lots of demand, the price might drop to meet that demand. 10. In IPv6 addresses are 128 bits. If the first 100 bits are fixed, then the last 28 bits can vary. This means there are 2^28 different addresses with the same first 100 bits.