In a book by Forouzan (https://www.amazon.com/Data-Communications-Networking-McGraw-Hill-Forouzan/dp/0072967757) I've read that the sequence number of the authentication header doesn't get repeated even if a packet is retransmitted.
If the sequence number is not repeated then I could potentially keep on sending same packets and receiver will think that they are different because they have different sequence numbers.
How does that prevent replay attack?