Ubee ddw3611 User Manual page 50

4.6 Wifi Multimedia
to as a user priority (UP). An AC may include a common set of enhanced distributed
channel access (EDCA) parameters that may be used by QoS to contend for a
channel in order to transmit packets with certain priorities.
Different ACs may be associated with different power saving parameters. One such
power saving parameter may be, for example, the delivery mechanism used by an
access point (AP) to deliver packets to a station (STA) that is operating in a reduced
power mode. For example, one delivery mechanism may be the "legacy" power save
mechanism of the IEEE 802.11 standard: "ANSI/IEEE Std. 802.11, Information
technology—Telecommunications and information exchange between systems—Local
and metropolitan area networks—Specific requirements—Part 11: Wireless LAN
Medium Access Control (MAC) and Physical Layer (PHY) Specifications" (published
1999; reaffirmed June 2003). Another delivery mechanism may be the automatic
power save delivery (APSD) mechanism, e.g., unscheduled APSD (UAPSD) or
scheduled APSD (S-APSD), as defined in 802.11e. A QoS station (QSTA) may define
all or some of the ACs as trigger-enabled and/or delivery-enabled. A trigger- and
delivery-enabled AC may use UAPSD as the default delivery mechanism, whereas an
AC that is neither trigger- nor delivery-enabled may use the "legacy" power save
delivery mechanism.
46 DDW3611 Subscriber User Guide • May, 2010
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