Posted 14 July 2010 - 11:53 AM
This process is not in the standard and left up to individual manufacturers to implement, so the only possible answer is the ubiquitous "it depends". Not very satisfactory, I know. Also be aware that the G or B device doesn't even have to be associated with your AP to slow things down. If it's even in the neighborhood and using the same channel the AP will go into compatibility mode so as not to break the Media Access Control protocol, which coordinates over-the-air transmissions between all radios that can "hear" each other on a given channel, even if they are different AP's or Clients on different networks. Compatibility mode shuts off or limits many of the N features. There are still advantages, even in this mode, resulting in better throughput and range than with a G AP, but not nearly as much as in a "pure" (or, in the standards, "Greenfield") N environment.