Cisco 6861 Deployment Manual page 19

If the Stream feature is enabled either directly or via selecting Optimized Voice for the radio access category in the QoS
configuration section, then use the default settings, where 5.5, 6, 11, 12, and 24 Mbps are enabled as nominal rates for
802.11b/g, 6, 12, and 24 Mbps are enabled for 802.11a, and 6.5, 13, and 26 Mbps are enabled for 802.11n.
If the Stream feature is enabled, ensure that only voice packets are being put into the voice queue. Signaling packets (SIP)
should be put into a separate queue. This can be ensured by setting up a QoS policy mapping the DSCP to the correct
queue.
Cisco IP Phone 6861 Multiplatform Phones Wireless LAN Deployment Guide
19