adjusted_rtt

[Timo Völker <[e-mail]>]

Hi,

I noticed in a simulation with a constant RTT that the smoothed_rtt value includes the ack_delay. It looks like my implementation follows the recovery draft. By looking closer, I believe I found a tiny error in the draft.

Section 5.3 contains this sentence.

"MUST NOT subtract the acknowledgment delay from the RTT sample if the resulting value is smaller than the min_rtt."

I interpret this as do not subtract ack_delay from latest_rtt if

  latest_rtt - ack_delay < min_rtt

Or to say the inverse, substract ack_delay from latest_rtt if

  latest_rtt - ack_delay >= min_rtt
  <==> latest_rtt >= min_rtt + ack_delay
  <==> min_rtt + ack_delay <= latest_rtt

The pseudo code in Section 5.3 and in the appendix use a smaller instead of an equal or smaller in the if statement.

  if (min_rtt + ack_delay < latest_rtt):

It should be <= or did I miss something?

Timo