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How to use 802.11e (prioritization) on the Open BAT WLAN interfaces - Knowledgebase / Products / BAT / BAT, WLC (HiLCOS) - Belden Support Center

How to use 802.11e (prioritization) on the Open BAT WLAN interfaces

802.11e is quite easy to enable on the OpenBAT. By default it's even enabled.
It makes possible the sending of traffic on the WLAN interfaces using 4 priority queues.

To process a frame or packet accordingly to priority rules, the BAT relies on 2 things:
802.1p (priority contained in VLAN tagged frames).
If there's no VLAN tag then it uses the Diffserv field.

The ideal case would consist in having end devices (such as IP phones) able to send trafic with a priority value present in the Diffserv field.
In this case, no need to do VLAN configuration on the Open BAT or on the devices around.
But a mapping between the DSCP value and the priority queue (Access Category) must nevertheless be configured.
This mapping can be done via the Web interface under:
HiLCOS-Menu-Tree > Setup > LAN-Bridge > Priority Mapping

The table below may help you for the mapping (take care that in rel 9.10 the ToS value in decimal must entered)

CoS = Class of Service
DSCP = Differentiated Services Code Point
ToS = Type of Service
AF = Assured Forwarding
IPP = IP Precedence
CS = Class Selector
DP = Drop Probability
 
Application CoS=IPP AF DSCP ToS ToS_HEX DP
Scavanger 1 CS1 8 32 20  
Bulk-Data 1 AF11 10 40 28 Low
- 1 AF12 12 48 30 Medium
- 1 AF13 14 56 38 High
Network_Mgmt. 2 CS2 16 64 40  
Transaction_Data 2 AF21 18 72 48 Low
- 2 AF22 20 80 50 Medium
- 2 AF23 22 88 58 High
Call_Signaling 3 CS3 24 96 60  
Mission-Critical 3 AF31 26 104 68 Low
Streaming-Video 3 AF32 28 112 70 Medium
- 3 AF33 30 120 78 High
- 4 CS4 32 128 80  
Interactive-Video 4 AF41 34 136 88 Low
- 4 AF42 36 144 90 Medium
- 4 AF43 38 152 98 High
- 5 CS5 40 160 A0  
Voice 5 EF 46 184 B8  
Routing 6 CS6 48 192 C0  
- 7 CS7 56 224 E0  



If it's not the case (No priority defined in the Diffserv field) then "unfortunately" traffic must be differentiated using the 802.1p field. In other words the upstream L2 network must prioritize the traffic (on layer 2) and the Open BAT must have a VLAN configuration to allow the forwarding of tagged frames.

Assigning a 802.1p prio can be done letting all the devices in VLAN 1 (default VLAN). Per default, VLAN 1 frames are sent untagged, it means that the 802.1p field is missing. If we want to use priority based on 802.1p but don't want to separate traffic in different VLANs then we just have to take care that:
- VLAN 1 frames are sent tagged to the Open BAT and have a priority index.
- The Open BAT has the VLAN module enabled and has a VLAN configuration to send and  receive VLAN 1 tagged frames on the LAN and on the WLAN interface.

To make a VLAN configuration on the Open BAT you can refer to the lesson "How to configure VLANs on the OpenBAT"