Sliding Window Based- Go-back-N ARQ

• Damaged Frame

  • B has correctly received frames up to I-1, A sends I, B detects error, sends NAK I
  • frame I lost in transit, I+1 sent, B receives I+1 out of order, sends NAK I, else
  • A sends nothing after I, hears nothing, resends after timeout

• Damaged ACK

  • B receives I, sends ACK I+1 which is lost, A may receive subsequent ACK or timeout

• Damaged NAK

  • A will eventually timeout and resend all

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