It doesn't appear to be a "multi-verse" (where we'd find uncountable varieties of Nanoha or no-Nanoha). It just appears to be a "hyperspacey" way of getting from Plain Old Point A to Plain Old Point B. There do seem to be pocket universes (or mini-universes) that can be reached via it though --- probably best not to peer too closely or what you'll really see is a pack of writers who failed or never took physics
