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Contributors

• Fat-tree
• MPTCP
• BBR
• PIFO

🔗高级计算机网络期末复习PPT

Fat-tree

• Addressing
• Two-level routing table
• Routing algorithm
  • Pod switch: upward, downward
  • Core switch

MPTCP

• EWTCP vs. Coupled
• EWTCP
  • Subflows are independent
• Coupled $w_{total}\approx \sqrt{2/p}$

BBR

• Understand the three regions
  • Application limited
  • Bandwidth limited
  • Buffer limited
• When packet starts to queue?
• When packet starts to be dropped?
• Where loss-based congestion control works?
• Where BBR works?

PIFO

• Start time fair queueing
• Two flows, A and B, $w_A=0.8$ and $w_B=0.2$, both flows have many packets arriving to the switch, no restriction on queue length, assume no dequeues and packet size is 1
  • For flow A, a0.rank=0, a1.rank=1.25, a2.rank=2.5, a3.rank=3.75, a4.rank=5, a5.rank=6.25, …
  • For flow B, b0.rank=0, b1.rank=5, b2.rank=10, …
  • The PIFO dequeue sequence is a, b, a, a, a, a, b, a, a, a, b, …