Руководство По Проектированию для Cisco Cisco Aironet 350 Mini-PCI Wireless LAN Client Adapter
5-12
Enterprise Mobility 4.1 Design Guide
OL-14435-01
Chapter 5 Cisco Unified Wireless QoS
Wi-Fi Multimedia
Figure 5-10
Probe Response WMM Element Information
U-APSD
Unscheduled automatic power-save delivery (U-APSD) is a feature that has two key benefits:
•
The primary benefit of U-APSD is that it allows the voice client to synchronize the transmission and
reception of voice frames with the AP, thereby allowing the client to go into power-save mode
between the transmission/reception of each voice frame tuple. The WLAN client frame transmission
in the access categories supporting U-APSD triggers the AP to send any data frames queued for that
WLAN client in that access category. A U-APSD client remains listening to the AP until it receives
a frame from the AP with an end-of-service period (EOSP) bit set. This tells the client that it can
now go back into its power-save mode. This triggering mechanism is considered a more efficient use
reception of voice frames with the AP, thereby allowing the client to go into power-save mode
between the transmission/reception of each voice frame tuple. The WLAN client frame transmission
in the access categories supporting U-APSD triggers the AP to send any data frames queued for that
WLAN client in that access category. A U-APSD client remains listening to the AP until it receives
a frame from the AP with an end-of-service period (EOSP) bit set. This tells the client that it can
now go back into its power-save mode. This triggering mechanism is considered a more efficient use