Algorithm 1: ProbeBW phase in BBR-GC

Input: rtt_us, inflight, has loss//The value of rtt_us is updated when an ACK is received Output: pacing gain 1:  RTTmin = min (RTTmin, rtt_us); 2.  RTTmax = max (RTTmax, rtt_us); Phase 1: probe up 3.  For every ACK do 4:  if inflight < 1BDP then 5:   pacing_gain = Pup 6:   return 7:  end if 8:  if pacing_gain < 1.0 and inflight < 1BDP then 9:   pacing_gain = 1.0 10:   end if Phase 2: probe down 1:  if inflight > 1.25BDP or has loss then 2:   pacing_gain = Pdown 3:  return 4:  end if Phase 3: next six cycles 1:  if pacing gain == 1.0 then 2:  return 3:  end if