A mechanism for establishing a plurality of sessions between a client and a first server based on a single input of user authenticating information is disclosed. In one form, the invention comprises a transverse stent comprising a superior border opposed to an inferior border, an inner surface and an outer surface. To achieve effective passive compensation of dynamic hydraulic pressures with comparatively little radial structural space occupation, at least two pressure compensation spaces, opposite the engaging pressure space, are arranged in a cylinder space of the shifting element piston axially next to one another. 709 OTN frame including an OTU overhead section and an ODU section. The invention also relates to a water purification method.