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 the greater the likelihood of generating an additional ATM cell. A worst case might be sending 3 ATM cells instead of two because of a 44 byte header overhead compared with a 10 byte header overhead, so 50% more time taken to transmit the data. For example a TCP ACK packet over IPv6 is 60 bytes long, and with overhead of 40 or 44 bytes for PPPoEoA + LLC this requires three 48 byte ATM cells’ payloads. As a comparison, PPPoA with overheads of 10 bytes so 70 bytes total fits into two cells. So the extra cost of choosing