Sorry Tobi, not intending to imply that Smokeping is "fatally flawed". I am simply trying to understand how the "loss" field is calculated and how we have, for example, a 92.1% in the packet loss field of an rrd record.
Thanks for jumping in. As the creator of Smokeping, I am confident that you will provide an answer that I can pass on to those in the corporation who are asking for this to be explained. Vern -----Original Message----- From: Tobias Oetiker [mailto:[EMAIL PROTECTED] Sent: Monday, February 12, 2007 10:12 AM To: Dias, Vern Cc: [email protected] Subject: Re: [smokeping-users] Packet loss calculations in Smokeping Hi Vern, Today [EMAIL PROTECTED] wrote: > There are never any NAN values that I have found in the actual latency > fields, regardless of the number of lost pings. To me this means that > any attempt at having rrdtool calculate an accurate packet loss value > is doomed from the start. Looks to me like rrdtool is attempting to > calculate all latency values. note that the first 3 fields in the RRD file are not round trips, but the results of the analysis of the pings sent out in each round. We store this data explicitly since it can not be rebuilt later from what is stored in the rrd file: 0 - uptime - this is for measuring ip retention time with dynamic ips this is set to NaN unless you use this feature 1 - loss - the number of lost packets 2 - median - the median round trip time 3-n - ping[1-n] - the ping latency the roundtrip times are 'sorted'. if not all pings are successful the successfull ones are positioned n the middle > Seems to me, that in the case of a packet loss situation within a > single poll, it is up to Smokeping to feed actual data from all 10 > polls to rrdtool, even if one or more or all of the polls are timeouts. it does this ... but as you explained earlier, since the pings do not arrive at 'step-time' it takes normally two losses in a row to manifest them selfs in the log ... regarding your 'analysis' ... don't you think something so fatally flawed would have triggerd some discussion in all the years smokeping has been around ? if you check the mailinglist archives you will see that it has and eventually people understood how the data is handled, and why it happens the way it does ... cheers tobi -- Tobi Oetiker, OETIKER+PARTNER AG, Aarweg 15 CH-4600 Olten http://it.oetiker.ch [EMAIL PROTECTED] ++41 62 213 9902 The information contained in this message and any attachment may be proprietary, confidential, and privileged or subject to the work product doctrine and thus protected from disclosure. If the reader of this message is not the intended recipient, or an employee or agent responsible for delivering this message to the intended recipient, you are hereby notified that any dissemination, distribution or copying of this communication is strictly prohibited. If you have received this communication in error, please notify me immediately by replying to this message and deleting it and all copies and backups thereof. Thank you. _______________________________________________ smokeping-users mailing list [email protected] https://lists.oetiker.ch/cgi-bin/listinfo/smokeping-users
