Nadir is employed during remote sensing of the atmosphere, as well as when an astronaut faces the Earth while performing a spacewalk. The term nadir can also be used to represent the lowest point reached by a celestial body during its apparent orbit around a given point of observation. This can be used to describe the location of the Sun, but it is only technically accurate for one latitude at a time and only possible at the low latitudes. The sun is said to be at the nadir at a location when it is at the zenith at the location's antipode
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