FreeBSD em, igb driver question

[Nomad Esst]

Hi allDuring some performance tests, we found out some weird problems. We use a shell script that do the following :
do from 1 to 10Shutdown em/igb interfacesleep 3Bring em/igb interface uptcpreplay -i em0 -l ospf_hello.pcap sleep3end
By running this shell on one side we expect 10 ospf hello packets to get arrived at the other side, but tcpdump (on the other side) shows 4, sometimes 8 and etc ... (not all 10 packets are arrived at the other side).We test this scenario with a Cisco router, and all packets are received at the Cisco side. What causes this packet loss in FreeBSD (maybe in em or igb drivers)?I know that this scenario may not have any use in the real world, but I'm curious, why Cisco don't have such behavior.Thanks in advance.
Regards.