Odd Network Access icon behaviour.

I have noticed that the little blue ball/circle disappears for a few seconds on the Network Access icon in the systems tray sometimes (Vista). That is the one in front of the two monitor icons that can display in an animated way. I have not noticed this phenomenon before much. I know it displays a red cross when there is no connection & an exclamation mark when there is some problem. I just wondered if it was necessarily unusual or anything to worry about.

 

It takes a few seconds during boot-up for it to appear. It is normally constant after that. It seems to disappear sometimes, usually for a few seconds in certain websites. Well, usually in MozillaZine for some strange reason. I just wondered if anyone else had noticed anything like it. I know it can fluctuate if the connection is broken temporarily. This can happen if your provider has been tweaking the broadband, as has happened recently with mine. They did tell me about it. I was wondering if it is symptomatic of anything?