Nadir Nadir The nadir (, ; from / ALA-LC: "naẓīr", meaning "counterpart") is the direction pointing directly "below" a particular location; that is, it is one of two vertical directions at a specified location, orthogonal to a horizontal flat surface there. Since the concept of "being below" is itself somewhat vague, scientists define the nadir in more rigorous terms. Specifically, in astronomy, geophysics and related sciences (e.g., meteorology), the nadir at a given point is the local vertical direction pointing in the direction of the force of gravity at that location. The direction opposite the nadir is the zenith. Nadir is
Point-to-Point Protocol over Ethernet computer or from the DSL-AC. PPPoE is used to connect a PC or a router to a modem via an Ethernet link and it can also be used in Internet access over DSL on a telephone line in the "PPPoE over ATM" (PPPoEoA) over ADSL protocol stack. PPPoE over ATM has the highest overhead of the popular DSL delivery methods, when compared with for example PPPoA (RFC 2364). The amount of overhead added by PPPoEoA on a DSL link depends on the packet size because of (i) the absorbing effect of ATM cell-padding (discussed below), which completely cancels out additional