Hello Ana, I took a very quick look in the traceroute code, see here: https://github.com/RIPE-NCC/ripe-atlas-probe-measurements/blob/7c03fba082e93b7a1f0f14cc3769bb31e83909e3/eperd/traceroute.c ripe-atlas-probe-measurements/traceroute.c at 7c03fba082e93b7a1f0f14cc3769bb31e83909e3 · RIPE-NCC/ripe-atlas-probe-measurements github.com It seems that a sequence number in the traceroute packet is used. If this sequence number is received back it’s marked as ‘response received’. If another response is received within a certain timeframe, it’s tagged as a duplicate. Otherwise its a late packet. Hope it helps. Cheers, Michel
On 20 Jan 2023, at 11:38, Ana Custura <ana@erg.abdn.ac.uk> wrote:
Hi everyone,
Just a question on how Atlas detects duplicate ('dup') packets in a traceroute.
Is the 'dup' field added to a result when two received packets are exactly the same, regardless of whether they were received for a different initial TTL?
Or are any packets that were unexpectedly received for a specific TTL marked as duplicates (e.g. if you receive 6 replies from 2 different IP addresses to the 3 initial packets sent with TTL 1, will 3 of these replies be marked as duplicates)?
Thanks for your help!
Regards, Ana -- ripe-atlas mailing list ripe-atlas@ripe.net https://lists.ripe.net/mailman/listinfo/ripe-atlas
