Ruh Roh
RIP Network
Bye-bye Bandwidth
Time After Time
True Lies
100

T/F: If a network request doesn't get a response, it is impossible to tell why

True

100

T/F: Handling network faults means we need to tolerate them

False -- does NOT mean we need to tolerate them

100

T/F: When a circuit is idle, it doesn't use any bandwidth.

False -- It does, TCP doesn't

100

T/F using clock syncing for distributed transaction semantics has only been implemented at one company. 

T -- Google

100

T/F: A synchronous model assumes unbounded network delays, unbounded process pauses, and unbounded clock errors

False

200

Which of the following could potentially cause a network problem? 

  1. Software upgrade
  2. Sharks biting undersea cables
  3. Dropping of inbound packets but sending outbound packets successfully
  4. All the above
  1. All the above
200

What is the dominant approach for building internet services?

  1. Shared-memory
  2. Shared-disk
  3. All of the above
  4. None of the above
  1. None of the above -- shared-nothing
200

T/F: Latency guarantees can be achieved if resources are statically partitioned

True -- With dedicated hardware and exclusive bandwidth allocation

200

What is the date that epoch started since midnight UTC?

  1. 1/1/1911
  2. 1/1/1970
  3. 12/31/1960
  4. 12/31/1970

B. 1/1/1970

200

What does it mean to be Byzantine fault-tolerant?

  1. Handles network delays
  2. Withstands malicious attackers
  3. Corrects malfunctioning nodes
  4. All the above
  5. B & C

B. Withstands malicious attackers

300

What might cause a stop-the-world incident?

  1. Garbage collection
  2. VM pausing
  3. OS screen saver

A. Garbage collection

300

What is the way for handling a network request issue? 

  1. 400 error
  2. Negative response from the app
  3. Timeout
  4. Request receipt
  1. Timeout
300

Asynchronous networks may have:

  1. Bounded delays
  2. Unbounded delays
  3. None of the above

B. Unbounded delays

300

What do we call when the frequency at which the monotonic clock moves forward?

  1. Skipping
  2. Sharding
  3. Shifting
  4. Slewing
  5. Stewing

D. Slewing

300

What is not an example of weak form of lying?

  1. Corrupted network packets
  2. Software bugs
  3. Radiation

B. Software bugs

400

Byzantine generals suffered from what issue?

  1. Plague
  2. Slow messengers
  3. Slow distributed systems
  4. Traitors

D. Traitors

400

What is it called when part of a network is cut off from the rest due to a network fault?

  1. Network partition
  2. Network shard
  3. Netsplit
  4. B & C
  5. A & C
  1. A & C
400

Which protocol will retransmit missing packets?

  1. IP (Internet Protocol)
  2. TCP (Transmission Control Protocol)
  3. UDP (User Datagram Protocol)
  4. None of the above
  5. All of the above

B. TCP (Transmission Control Protocol)

400

What is the offset when syncing time from a server?

  1. Time uncertainty based on the expected quartz drift since last sync
  2. NTP server's uncertainty
  3. Network round-trip time to the server
  4. All of these

D. All of these

400

What is not a property for an algorithm to be correct?

  1. Availability
  2. Scalability
  3. Distinctness
  4. Monotonic sequence
  5. A & B
  6. B & C
  7. All the above

F. B & C

500

Which accurately describes faults and partial failures?

  1. Faults are deterministic in a single computer
  2. Faults are deterministic in a DS
  3. Partial failures are nondeterministic in a single computer
  4. Partial failures are nondeterministic in a DS
  5. A & D
  6. B & C

E. A & D

500

What is not a way to handle network congestion?

  1. UDP flow control
  2. OS queue
  3. VM monitor
  4. Switch queue

A. UDP flow control

500

What is it called when a packet must wait to get a slot?

  1. Network tolerance
  2. Network interference
  3. Network congestion
  4. All of the above
  1. Network congestion
500

Which is not a factor that influences NTP syncing?

  1. Network delays
  2. Servers could be wrong or misconfigured
  3. Leap minutes that result in an hour
  4. NTP daemon configuration
  5. Firewall blocking NTP traffic

C. Leap minutes that result in an hour

500

For distributed system algorithms, which property(ies) always hold?

  1. Availability
  2. Monotonic sequence
  3. Liveness
  4. All the above

B. Monotonic sequence

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