Cisco Cisco Aironet 350 Mini-PCI Wireless LAN Client Adapter Guia Do Desenho
5-22
Enterprise Mobility 4.1 Design Guide
OL-14435-01
Chapter 5 Cisco Unified Wireless QoS
802.11e, 802.1P, and DSCP Mapping
802.11e, 802.1P, and DSCP Mapping
WLAN data in a Unified Wireless network is tunneled via LWAPP (IP UDP packets). To maintain the
QoS classification that has been applied to WLAN frames, a process of mapping classifications to and
from DSCP to CoS is required.
QoS classification that has been applied to WLAN frames, a process of mapping classifications to and
from DSCP to CoS is required.
For example, when WMM classified traffic is sent by a WLAN client, it has an 802.1P classification in
its frame. The AP needs to translate this classification into a DSCP value for the LWAPP packet carrying
the frame to ensure that the packet is treated with the appropriate priority on its way to the WLC. A
similar process needs to occur on the WLC for LWAPP packets going to the AP.
its frame. The AP needs to translate this classification into a DSCP value for the LWAPP packet carrying
the frame to ensure that the packet is treated with the appropriate priority on its way to the WLC. A
similar process needs to occur on the WLC for LWAPP packets going to the AP.
A mechanism to classify traffic from non-WMM clients is also required, so that their LWAPP packets
can also be given an appropriate DSCP classification by the AP and the WLC.
can also be given an appropriate DSCP classification by the AP and the WLC.
shows the various classification mechanisms in the LWAPP WLAN network.
Figure 5-22
WMM and 802.1P Relationship
The multiple classification mechanisms and client capabilities require multiple strategies:
•
LWAPP control frames require prioritization, and LWAPP control frames are marked with a DSCP
classification of CS6.
classification of CS6.
•
WMM-enabled clients have the classification of their frames mapped to a corresponding DSCP
classification for LWAPP packets to the WLC. This mapping follows the standard IEEE
CoS-to-DSCP mapping, with the exception of the changes necessary for QoS baseline compliance.
This DSCP value is translated at the WLC to a CoS value on 802.1Q frames leaving the WLC
interfaces.
classification for LWAPP packets to the WLC. This mapping follows the standard IEEE
CoS-to-DSCP mapping, with the exception of the changes necessary for QoS baseline compliance.
This DSCP value is translated at the WLC to a CoS value on 802.1Q frames leaving the WLC
interfaces.
Table 5-6
Downstream Traffic
Traffic Stream Established
No Traffic Stream
No admission control
No change
No change
Admission control
No change
Remark UP to BE for WMM client.
For non-WMM clients, use WLAN
QoS.
For non-WMM clients, use WLAN
QoS.
Clients
Controller
802.11e
1
DSCP
2
802.1p DSCP
3
153876
LWAPP
LWAPP
Si
LWAPP
LWAPP
LW
APP
LW
APP
dot1q