Explanation/Reference:
Section: Considerations for Expanding an Existing Network Explanation
Explanation:
Wi-Fi Multimedia (WMM) treats unassigned traffic as though it were assigned to the Silver access category. WMM is a subset of the 802.11e wireless standard, which adds Quality of Service (QoS) features to the existing wireless standards. WMM was initially created by the Wi-Fi Alliance while the 802.11e proposal was awaiting approval by the Institute of Electrical and Electronics Engineers (IEEE).
The 802.11e standard defines eight priority levels for traffic, numbered from 0 through 7. WMM reduces the eight 802.11e priority levels into four access categories, which are Voice (Platinum), Video (Gold), Best-Effort (Silver), and Background (Bronze). On WMM-enabled networks, these categories are used to prioritize traffic. Packets tagged as Voice (Platinum) packets are typically given priority over packets tagged with lower-level priorities. Packets that have not been assigned to a category are treated as though they had been assigned to the Best-Effort (Silver) category.
When a lightweight access point (LAP) receives a frame with an 802.11e priority value from a WMM- enabled client, the LAP ensures that the 802.11e priority value is within the acceptable limits provided by the QoS policy assigned to the wireless client. After the LAP polices the 802.11e priority value, it maps the
802.11e priority value to the corresponding Differentiated Services Code Point (DSCP) value and forwards the frame to the wireless LAN controller (WLC). The WLC will then forward the frame with its DSCP value to the wired network.
Reference:
CCDA 200-310 Official Cert Guide, Chapter 5, Wireless and Quality of Service (QoS), pp. 197-199 Cisco: Cisco Unified Wireless QoS