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 PPPoA which at 1500 + 2 (PPP) + 0 (PPPoA: RFC 2364 VC-MUX) + 8 (CPCS trailer) = 1510 bytes fits in 32 cells. So the real cost of choosing PPPoEoA plus RFC2684-LLC for 1500-byte IP packets is one additional ATM cell per IP packet, a ratio of 33:32. So for 1500 byte packets, PPPoEoA with LLC is ~3.125% slower than PPPoA or optimal choices of PPPoEoA header options. For some packet lengths the true additional effective DSL overhead due to choosing PPPoEoA compared with PPPoA will be zero if the extra header overhead is not enough to need an