Live smooth streaming Client - First fragment selection

Hi All,

I have a question regards first fragment selection in "live" streaming.When dealing with "On Demand" streaming it is clear that first fragment to play is the first fragment declared in manifest. When dealing with "Live" streaming the situation is a bit different, and a couple of questions:

When starting to play live  smooth streaming "manifest" containing first few fragments descriptors is obtained. Question is what fragment should client try to play first ? and what fragments (out of the fragments described in manifest) are guaranteed to be available?

Should i start my playback with the "last" available fragment ?/first one ?

Are fields like "DVBWindow and Lookeheadcount" somehow relevant for the selection of the first fragment to play ?

Thanks,

Regards Sasha