Junos Non-Stop Active Routing and Fault-Tolerant TCP/IP test setup; https://cseweb.ucsd.edu/~marzullo/pubs/fttcp2.pdf

packet_capture_in_g-bird1.txt

root@bird1:~# # acknowledgements to the client(10.10.10.1) are withheld until the hot backup has received the corresponding data
root@bird1:~# tshark -c 4 -i enp7s0 -f 'tcp and port 179'
Running as user "root" and group "root". This could be dangerous.
Capturing on 'enp7s0'
    1 0.000000000   10.10.10.1 → 10.10.10.0   BGP 85 KEEPALIVE Message
    2 0.601193559   10.10.10.0 → 10.10.10.1   TCP 66 179 → 60153 [ACK] Seq=1 Ack=20 Win=16384 Len=0 TSval=2273170037 TSecr=1268402651
    3 4.135022182   10.10.10.0 → 10.10.10.1   BGP 85 KEEPALIVE Message
    4 4.135067259   10.10.10.1 → 10.10.10.0   TCP 66 60153 → 179 [ACK] Seq=20 Ack=20 Win=126 Len=0 TSval=1268406786 TSecr=2273173570
4 packets captured
root@bird1:~#