I am trying to understand how the DSCP markings are handled for the LAP to WLC and WLC to LAP with and without WMM clients. What I am reading in this Cisco document vs what I am seeing in actual packet captures is not the same.
Can someone explain to me how the CAPWAP DSCP value is determined from LAP to WLC and WLC to LAP with and without WMM enabled. And/Or point me to Cisco documenation that explains it better than this document? I am trying to write QoS policies for the traffic inbound from the LAP and Controller and need to know what I should be expecting.
Below is an excerpt from QoS on Wireless WAN Controllers and Lightweight APs Configuration Example document. The full document can be found at the link below.
http://www.cisco.com/en/US/tech/tk722/tk809/technologies_configuration_example09186a00807e9717.shtml
Excerpt Start --
For a WMM enabled Video client:
3. Once the Video packets reach the WLC through the fastethernet on Router2, the WLC translates the
DSCP value of the incoming packet to the AVVID 802.1p UP value and copies the DSCP value from
the incoming packet to the LWAPP packet as shown here. In this example, the DSCP value AF41 is
translated to the corresponding 802.1p value 4
My Comments:
** In my case the traffic was http and configured with a QoS profile of Bronze, 802.11e UP value of 1 which according to the table is converted to DSCP 10 (AF11). The sniffer capture at the controller side showed that the CAPWAP packet being assigned a DSCP value of 0 and the internal packet being assigned a DSCP value of 0. As the QoS profile is Bronze should it not be placing the value of DSCP 10 into the CAPWAP field?\
When a Video client on the wireless side sends data to the wired side, this sequence of events occurs:
1. When a WMM enabled client sends a packet to the LAP, the LAP polices the 802.11e UP value in
order to ensure it does not exceed the maximum value allowed for the QoS policy assigned to that
client. Then, it translates the value to the DSCP value. In this example, the Video WLAN has been
configured with the QoS profile Gold, which has a 802.11e UP value of 4. This value is translated to
the corresponding DSCP value AF41 and is sent to the controller.
My Comments:
** In my case it was configured with a QoS profile of Bronze, 802.11e UP value of 1 which according to the table is converted to DSCP 10 (AF11). Am I interpretting this correctly as the sniffer capture shows that both the CAPWAP packet and the inner packet are being marked as DSCP 0.
