PollDevice set "Timestamp" option of header IP?

[Alessandro Baldisserri]

Hi,

I want to control the difference in time between the arrival of two packet in my
router. I think to use "timestamp_anno" method in a new click element written by
me, because I red in the documentation that FromDevice and PollDevice set the
timestamp annotation.
I have a question... The timestamp annotation that these elements set, is
TIMESTAMP option of header IP?? Or it's a purely annotation of my system clock?
Thanks in advance.

Alessandro