[Nfd-dev] RTT estimator

[Lan Wang (lanwang)]

Hi Junxiao,

We're implementing a forwarding strategy and using the RTT estimator you have in NFD.   While debugging some results, we looked at the RTO values computed by the RTT estimator.   It seems that the RTT estimator in NFD has several features that are different from the TCP retransmission timeout algorithm (https://tools.ietf.org/html/rfc6298).

1. you use the same multiplier (0.1) for SRTT and RTTVAR.  But in TCP, it's 0.125 for SRTT and 0.25 for RTTVAR.

2. you initialize the RTTVAR to be the same as the first RTT measurement.  But in TCP, it's initialized to 1/2 of the first RTT measurement.

I'm wondering why you made the above decisions.   Thanks.

Lan