[Nfd-dev] RTT estimator

[Junxiao Shi]

Hi Lan

NFD RttEstimator code is copied from NDNFD. This code is written according
to ns3::RttMeanDeviation.
I don't have particular reason for those differences from RFC6298.

Recent strategy design suggests that each strategy may need a different
RttEstimator.
Therefore, your strategy could duplicate RttEstimator and give it a
different name or make it a nested class, and then make changes.

Yours, Junxiao
On May 15, 2015 09:39, "Lan Wang (lanwang)" <lanwang at memphis.edu> wrote:

> 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
>
>
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