1. What was the primary goal when designing the original Internet? Why?

2. As a result of the primary goal, what functionality were Internet routers originally tasked with?

3. What would an Internet designed whose primary goal is predictable performance look like? There are multiple correct answers to this question.

4. Why does BBR use a windowed minimum to compute round-trip time estimates?

5. Conversely, why does BBR use a windowed maximum to compute bottleneck bandwidth estimates?

6. In the congestion avoidance and control paper, what property of the routers does the congestion control algorithm rely on?

7. What happens if this property is violated? What kinds of traffic does this affect?

8. How does BBR handle the network setting where this property is violated?

9. What advantage does XCP have over WFQ in terms of the router memory that each algorithm requires?

10. What performance property does WFQ provide that XCP doesn't?

11. Give an example of a network that violates the Gao-Rexford conditions. Show how routes oscillate as a result of this violation.

12. How does each router pick between alternate AS-level paths in BGP?

13. Give an example of transit and peering relationships in BGP.

14. Give one example use case for SDX that isn't supported easily by BGP.

15. Explain the difference between the scale-out and scale-up approaches to building large networks.

16. Conceptually how is traffic load balanced between different intermediate links in the VL2 network.

17. How do ECMP and VLB complement each other to achieve this load balancing in VL2?

18. How do routers signal congestion to end points in DCTCP?

19. How does DCTCP extract multi-bit feedback from single-bit congestion information in DCTCP?

20. What happens when the first packet of a new flow shows up at an Ethane switch?

21. What capabilities does the OpenFlow proposal provide?

22. What shortcomings of OpenFlow does P4 fix?

23. What kind of flexibility does RMT provide that wasn't previously available?

24. What kind of flexibility does RMT not provide?

25. What properties does TLS provide?

26. What properties does TLS not provide? Give an example of a system that does provide this property?

27. Describe the Heartbleed bug and the fix for the heartbleed bug.

28. What remote data does the Heartbleed bug allow an attacker to read?

29. What is the problem with replacing a certificate in response to Heartbleed but not changing your private key?

30. Why do censors (like those operating within the Great Firewall of China) perform active probing?

31. How successful do you think the 2005 Tor Traffic Analysis attack would be if it was carried out on the Tor network today? Why would the outcome be any different from the outcome in 2005?

32. What feature of cellular networks does Sprout rely on?

33. Why does the Saturator program in Sprout attempt to maintain a target delay between 750 ms and 3000 ms?

34. Why does the Saturator program use a separate phone for feedback?

35. What would happen if we replaced Sprout in the Sprout Tunnel with TCP Cubic? Would this achieve the same goals of high throughput and low delay as Sprout? If not, provide a counter example showing why it would not.

36. The LTEye paper relies on the control channel of LTE being unencrypted. Why do you think the control channel is unencrypted?

37. Describe one finding of the LTEye paper that is meaningful to policy makers deciding how spectrum should be allocated.

38. How does the LTEye paper decide what modulation and coding scheme to use for decoding the control channel's information?

39. What is the main technical challenge involved in achieving full duplex communication?

40. What is the difference between how the full duplex radio paper handles the analog and digital forms of self interference?

41. What happens if the channel matrix in MIMO is non-invertible? What is the physical interpration of this?

42. What is the difference between multi-user MIMO and MegaMIMO?

43. In the paper on censorship circumvention by Ensafi et al., what is the key weakness of the obfs2 protocol? How does obfs3 fix this?

44. What is perfect forward secrecy? Why is this important in the context of security attacks such as Heartbleed?