Congestive collapse occurs when a computer network is overwhelmed by traffic, often exacerbated by aggressive retrying of dropped packets. Answer the following about how to control congestion, for 10 points each.
[10e] Since this transport-layer protocol retransmits to achieve correctness, it needs congestion control algorithms to prevent collapse. This protocol contrasts with the “spray-and-pray” UDP protocol.
ANSWER: TCP [or Transmission Control Protocol]
[10m] This classic TCP congestion control algorithm maintains a window whose lengthening upon ACKs (“axe”) and shortening upon packet drops produces a characteristic sawtooth-shaped graph.
ANSWER: AIMD [or Additive Increase, Multiplicative Decrease]
[10h] TCP CUBIC, which is more conservative near the largest achieved window size, prevents congestion better when this quantity for a network is large since it spends less time waiting. Long fat networks have large values of this quantity.
ANSWER: delay-bandwidth product [accept mathematically equivalent descriptions]
<Alistair Gray, Other Science - Computer Science>