how to filter all retransmission

[4412]

hi guys,
I got a capture file with many retransmission. I want to define a filter to extract all packets retransmitted so that I can study the relation between retransmission and time. But howto?
thx

 

[GuRuGuRu]

you can get this with a Wireshark ..

You can make a filter with tcp analysis flag field.

With this filter,you can filter the retransmitted packets.