Question: What does `dropping duplicate packet from` mean? about fastd HOT 3 CLOSED

fastd doesn't resend any packets; duplicate packets are determined by their sequence number (which is assigned by fastd). So you seeing these messages means that something between your peers is duplicating fastd's UDP packets.

from fastd.

Thanks for the answer! What does age 0 mean?

from fastd.

Thanks for the answer! What does age 0 mean?

"age 0" means that the duplicate packet had the same sequence number as the latest valid received packet. When packets are both reordered and duplicated, a packet with an older sequence number can be received, which will show a higher age value.

fastd will accept reordered packets as long as the age (the difference between the highest seqno and the seqno of a packet received out-of-order) is at most 64 (64 is used so duplicate packets can be detected by storing a 64-bit wide bitfield of seen seqnos).

No sequence numbers exist in the null and null@lt2p methods, so for these methods, duplicate packets are not filtered out.

from fastd.