For QoS/WMM (EDCA) a mac80211 driver needs to have at least four queues. mac80211 will then program the queues according to the advertised access parameters. 

**Legend:** 
  * **MQ**: mac80211 queue 
  * **AC**: Access Class 
  * **ACI**: Access Class Index 

mac80211 queue mapping: 
|**AC** |**MQ** |
|BK |3 |
|BE |2 |
|VI |1 |
|VO |0 |

802.11 uses the following number scheme (cf. Table 7-36) 
|**AC** |**ACI** |
|BK |01 (1) |
|BE |00 (0) |
|VI |10 (2) |
|VO |11 (3) |

Therefore, we have: 
|AC |ACI |MQ |
|BK |1 |3 |
|BE |0 |2 |
|VI |2 |1 |
|VO |3 |0 |

Due to internal collisions (we don't really know what this means either) the queue numbering is important, and queue 0 is highest priority, 3 lowest. If your hardware has a different idea of queue priority, you may need to rewrite the queue number, but make sure to do it everywhere mac80211 passes a queue number (conf_tx, skb_get_queue_mapping). 

The user priority is used as follows (802.11-2007 table 9-1): 
|**UP** |**AC** |**Priority** |
|1 |BK |Lowest |
|2 |BK |. |
|0 |BE |. |
|3 |BE |. |
|4 |VI |. |
|5 |VI |. |
|6 |VO |. |
|7 |VO |Highest |

**TOS:** 

mac80211 currently determines the UP based only on the IPv4 TOS field, unless the packet priority is set to 256..263 with setsockopt(SO_PRIORITY), in which case this maps directly to the UP (priority - 256) for testing. 

The IPv4 TOS field maps into the UP as follows, but keep in mind that the lowest two bits of the TOS are reserved (or used for ECN): 
|**TOS** |**UP** |
|0 - 31 |0 |
|32 - 63 |1 |
|... |
|224 - 255 |7 |

**DSCP **(RFC 2474)**:** 

Alternatively you can set the IP_TOS with setsockopt, then you need to ask how DSCP maps into the UP. DSCP is defined in the Differentiated Services ([[DiffServ|DiffServ]]) model as the six most significant bits of the [[DiffServ|DiffServ]](DS) Field. 
|DS5 (P2) |DS4 (P1) |DS3 (P0) |DS2 |DS1 |DS0 |ECN |ECN |

The classes of DSCP in wide usage are: 
|**DSCP Class** |**Codepoint(s)** |
|Default |0x00 |
|Expedited Forwarding (EF) |0x2E |
|Assured Forwarding (AF1) |0xA, 0xC, 0xE |
|Assured Forwarding (AF2) |0x12, 0x14, 0x16 |
|Assured Forwarding (AF3) |0x1A, 0x1C, 0x1E |
|Assured Forwarding (AF4) |0x22, 0x24, 0x26 |

The 3 Precedence bits of DSCP (**P2, P1, P0**) are used for mapping to 802.1D tags and AC values as: 
|**P2 P1 P0** |**802.1D** |**AC** |
|0 0 0 |0 |BE |
|0 0 1 |1 |BK |
|0 1 0 |2 |BK |
|0 1 1 |3 |BE |
|1 0 0 |4 |VI |
|1 0 1 |5 |VI |
|1 1 0 |6 |VO |
|1 1 1 |7 |VO |

**Testing**: 
    * Use ping ( with -Q option, see manpage ) 
    * use iperf: <code>iperf -S 0xE0 -c <IP></code> 
    * Use iptables. Example session with 2 iperf streams: 
    *  * iptables -t mangle -A OUTPUT -p tcp –dport 5000 -j DSCP –set-dscp-class "EF" 
    *  * iptables -t mangle -A OUTPUT -p tcp –dport 5001 -j DSCP –set-dscp-class "BE"