Some Smokeping doubts

Hi all, I’m using Smokeping (http://oss.oetiker.ch/smokeping/) and I have some doubs that maybe you can answer: - Why Smokeping needs to be connected to internet even when I have only one Target to a host in my LAN ? - What is exactly the Standard deviation calculated at the bottom right of the graphs? Can it be interpreted as Jitter? Or is there another way to know the jitter? - Why sometimes when I add a new host, for the first minute I get a list of errors saying that the RDD file doesn’t exist? This happens commonly? Is there any way to solve this problem? Many thanks, Gabriel