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802.11 Power Management
Power management can extend the battery life of clients by allowing the client to sleep for
short periods of time while its messages are buffered by the AP.
You may need to balance wireless performance versus battery-life. Power management
imposes a more active use of the wireless medium, which might lead to more frequent
transmission delays experienced as slower network response times during file transfers.
With slower response times, the client may spend more time in operational mode resulting
in less effective power management. In such cases, disabling power management on the
client might result in better throughput performance.
The RoamAbout PC Card 802.11 power management is separate from any power
management function on your computer.
RoamAbout AP
The RoamAbout AP automatically supports 802.11 power management. The only
parameter that can be set is the Delivery Traffic Indication Message (DTIM) interval,
which sets the buffering time. The default value of 1 corresponds to 100 milliseconds of
sleep time. It is highly recommended that you do not change this value.
RoamAbout Client
You can enable or disable power management on a RoamAbout client. With power
management enabled, the client goes into sleep mode to minimize power consumption. The
wireless traffic is buffered in the AP that the client uses to connect to the network.
The client checks for network traffic addressed to the client at regular intervals. If there is
no traffic addressed to the client, the client returns to sleep mode. If traffic is buffered at the
AP, the client collects the buffered messages prior to returning to sleep mode. The
following discusses how power management can impact data throughput of the wireless
network.
Power management causes little or no difference in network performance when using
transaction processing applications, such as hand-held scanners or clients that use the
wireless network only to send and receive e-mail.
You may experience longer network response times when you transfer large files
between the network and the client while power management is enabled. The size of
the files and the recurrence of file transfers are a factor. If modifying a document over
the network, any auto save feature could cause frequent file transfers.
The AP could cause longer network response times if a number of clients use the same
AP for buffering messages while in sleep mode.
802.11 Power Management
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