300-360 · Question #1
A downstream packet that contains a DSCP value arrives at the WLC Ethernet interface from the wired source network. The WLC is configured for QoS WLAN 802.1p mapping. How does the WLC treat the…
The correct answer is B. The outer CAPWAP CoS is marked and capped and the inner DSCP maintains the original. When a Cisco WLC is configured with 802.1p QoS mapping, it translates the incoming DSCP value into a Layer 2 CoS (Class of Service / 802.1p) value for the outer CAPWAP tunnel header. This outer CoS value is 'capped,' meaning it cannot exceed the maximum QoS level permitted by…
Question
A downstream packet that contains a DSCP value arrives at the WLC Ethernet interface from the wired source network. The WLC is configured for QoS WLAN 802.1p mapping. How does the WLC treat the CAPWAP QoS marking when leaving the controller interface for the respective AP and final wireless client destination?
Options
- ANo outer CAPWAP or inner QoS tagging is applied.
- BThe outer CAPWAP CoS is marked and capped and the inner DSCP maintains the original
- CNo outer CAPWAP QoS tag is applied, but the original DSCP is maintained inside CAPWAP.
- DThe outer CAPWAP DHCP is marked and capped without any inner DSCP value.
How the community answered
(47 responses)- A4% (2)
- B57% (27)
- C28% (13)
- D11% (5)
Explanation
When a Cisco WLC is configured with 802.1p QoS mapping, it translates the incoming DSCP value into a Layer 2 CoS (Class of Service / 802.1p) value for the outer CAPWAP tunnel header. This outer CoS value is 'capped,' meaning it cannot exceed the maximum QoS level permitted by the WLAN QoS policy configured on the controller. Critically, the original DSCP value is preserved inside the CAPWAP encapsulation (the inner packet), so the wireless client ultimately receives the packet with the original DSCP intact. This behavior is specific to 802.1p mapping mode - the outer tunnel uses CoS while the inner payload retains DSCP.
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