ngrep o/p - [A], [AP]

[Evuraan::ഏവൂരാന്‍]

What does [A] and [AP] mean on a typical ngrep o/p?

# ngrep -i "keep-alive" port 80 -W byline


<snip>
T 192.168.1.100:80 -> 66.249.67.42:57891 [A]
T 66.249.67.42:43897 -> 192.168.1.100:80 [AP]
<snip>

I know T is for TCP, what does {A]  and  [AP] at the end of the line mean?

Many Thanks in advance..!