What exactly mean TSval and TSecr

edit

I readed, that TSER and TSval are Timestamp fields. But I didn't understud what exactly they are mean. For example I captured incoming ip-frame with fields :

TSval=1965859179 TSecr=2947993570

Is TSecr is timestamp when datagramm was send to me? Is 1965859179 seconds(msecs) since midnight or something else? If I use proxy, this timestamp belongs proxy or host, I did send request ? I hope, explained the problem.