Notes / GATE / Computer Networks

CH 01

Frequently asked formulas

Computer Networks · GATE

Key points

  • Usable hosts in a subnet = 2^(host bits) − 2.
  • TCP congestion: window doubles in slow start, +1 MSS per RTT after the threshold.
  • On timeout, threshold = cwnd / 2 and cwnd = 1 MSS.

Formulas & facts

Transmission delay
L / B
Propagation delay
d / v
Stop & wait efficiency
1 / (1 + 2a), a = Tp / Tt
GBN / SR window
N / (1 + 2a)
Min frame (CSMA/CD)
L ≥ 2 × Tp × B
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