Hi, This indeed looks like a weird underflow/overflow bug -- 4294967296 in the RTT value happens to be 2^32...
We'll see if we can find a bug around this. Regards, Robert On Sun, Nov 3, 2024 at 9:18 PM ripe--- via ripe-atlas <[email protected]> wrote: > > Hi, > > In the data to date of an NTP measurement (#80845985), I find a single > strange outlier with respect to the RTT value calculated: > > { > "fw": 5090, > "mver": "2.6.4", > "lts": 281, > "dst_name": "time2.cloud.tencent.com", > "ttr": 0.413039, > "dst_addr": "119.28.229.79", > "src_addr": "45.11.104.146", > "proto": "UDP", > "af": 4, > "li": "no", > "version": 4, > "mode": "server", > "stratum": 2, > "poll": 8, > "precision": 1.19209E-7, > "root-delay": 0.0000915527, > "root-dispersion": 0.0249329, > "ref-id": "647a24c4", > "ref-ts": 3939345482.4404373, > "result": [ > { > "origin-ts": 3939346062.989854, > "receive-ts": 3939346062.999974, > "transmit-ts": 3939346063.0000167, > "final-ts": 3939346062.995442, > "rtt": 4294967296.005545, > "offset": -0.007347 > } > ], > "msm_id": 80845985, > "prb_id": 7030, > "timestamp": 1730357262, > "msm_name": "Ntp", > "from": "45.11.104.146", > "type": "ntp", > "group_id": 80845985, > "stored_timestamp": 1730357293 > }, > > When I do the math by hand, the "rtt" value I get is 0.0055453, nicely > matching the fractional part found in the measurement data. > > Does anyone have an explanation as to where the weird integer part might > come from? Some overflow/underflow or other issue with decimal math on a > binary machine? (I am not sufficiently versed in computer science to > fully understand that topic, just that there are challenges in that area.) > > Thanks! > > Kind regards, > > R. > ----- > To unsubscribe from this mailing list or change your subscription options, > please visit: https://mailman.ripe.net/mailman3/lists/ripe-atlas.ripe.net/ > As we have migrated to Mailman 3, you will need to create an account with the > email matching your subscription before you can change your settings. > More details at: https://www.ripe.net/membership/mail/mailman-3-migration/ ----- To unsubscribe from this mailing list or change your subscription options, please visit: https://mailman.ripe.net/mailman3/lists/ripe-atlas.ripe.net/ As we have migrated to Mailman 3, you will need to create an account with the email matching your subscription before you can change your settings. More details at: https://www.ripe.net/membership/mail/mailman-3-migration/
