> On Dec 8, 2015, at 8:10 AM, Cullen Jennings (fluffy) <[email protected]> wrote: > > >> On Nov 11, 2015, at 4:09 PM, Alissa Cooper <[email protected]> wrote: >> >>> >>> The definitions of EWMA_BYTES_SENT and EWMA_BYTES_RCVD seem problematic. >>> >>> sent = alpha x sent_present + (1 - alpha) x sent >>> rcvd = alpha x rcvd_present + (1 - alpha) x rcvd >>> >>> As written these equations are not right because sent/rcvd appear on both >>> sides. It would be clearer to use last_sent and last_rcvd or some such on >>> the right-hand side of these equations. But this begs some bigger questions: >>> >>> - Does this place a requirement on all nodes implementing this >>> specification to have to calculate these values every 5 seconds? >>> - How are the values calculated the first time? >>> - How was the value of 5 seconds chosen? >>> >>> [Haibin] This is incorporated from the early RELOAD document. Maybe some >>> author of the RELOAD protocol can give a better explanation. >> >> This still has not been explained. >> > > I'm sure I know what this was meant to represent when it was written .... > > sent for time period t should be set to the value of alpha times the amount > sent in this time period plus (1-alpha) times the value of send for the > previous time period. > > The value sent for the very first time period should simply be the amount > that was sent in that time period. That is not computable before the end of > the time period. I doubt anyone cares what the values before the end of the > first time period. Note that alpha is a constant that is probably compiled > into the application and not something we expect end users to set.
Thanks Cullen. I think the draft needs some text to explain the above. Haibin, do you think you could draft something up? Alissa > > Basically this is a somewhat crappy infinite impulse response (IIR) filter > approximation of finite impulse response (FIR) filter for computing the > weighted moving average of the data transmission rate. > > Dito for rcvd. > > Hope that helps, > > Cullen > > > As an irrelevant side note .. In practice, I have found that just reporting > the raw totals number of bytes sent since the box booted then letting the > management system filter and smooth that values works out better than using > this > > > > > _______________________________________________ P2PSIP mailing list [email protected] https://www.ietf.org/mailman/listinfo/p2psip
