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 4-byte Ethernet MAC FCS, which reduces the figure of 18 bytes above to 14, and (ii) by using the RFC 2684 VC-MUX option, which reduces the 10 byte LLC overhead down to 2 bytes. It turns out that this can be a very valuable efficiency improvement. Using VC-MUX instead of LLC, the ATM payload overhead would be either 32 bytes (without Ethernet FCS) or 36 bytes (with FCS). ATM AAL5 requires that an 8-byte long ‘CPCS’ trailer must always be present at the very end of the final cell (‘right justified’) of the run of ATM cells that make up