Challenges and Issues
Power management

Power consumption is always an issue with laptops, because the power and the battery have limited lives. As shown in Figure , three modes for power are available with Cisco PC cards:

  1. Constant awake mode (CAM): This mode is best for devices when power is not an issue, such as when AC power is available to the device. This mode provides the best connectivity option and the most available wireless infrastructure from the client perspective.
  2. Power save mode (PSP): This mode should be selected when power conservation is of the utmost importance. In this situation, the wireless NIC will go to sleep after a period of inactivity and periodically wake to retrieve buffered data from the AP.
  3. Fast power save mode (FastPSP): This mode is a combination of CAM and PSP. This is good for clients who switch between AC and DC power.