Regular Frameset - can be reframed, title stays the same regardless of body content, etc.
Protected Frameset - framing is restricted, title may be updated to reflect contents.
Each possible set of frames within the frameset has (the possibility of) a unique URL, which may be bookmarked. Each individual frame page can have a link to the correct parent frameset.
Frame names (and the reserved name title) are coded in the URL using the HTML FORM METHOD=GET convention. If slash "/" characters are required, some changes may be necessary.
This page discusses some of the problems of robots indexing frameset documents.
Andrew Daviel, Vancouver Webpages