Re: QoS prioritization doesn't work correctly and no QoS control fields

On Mon, 2008-12-08 at 22:03 +0800, Marco Talunzo wrote:
> Hi all,
> 
> I'm trying to work with QoS and have some problems. 
> 
> After installation of ieee80211-1.2.18 and ipw2200-1.2.2, I see that
> prioritization is somehow works. This is how I mark the packets (with
> iptables):
> 
> DSCP         AC
> 0x08  -->  AC_BK
> 0x00  -->  AC_BE
> 0x28  -->  AC_VI
> 0x30  -->  AC_VO
> 
> With some debugging code in ipw2200.c I observe that all packets
> correctly go to different transmission queues according to markings.
> 
> PROBLEM 1: when I observe the throughput produced at each access
> category I see that packets in AC_VO get transmitted with the highest
> priority (that's fine), but there is no any difference in performance
> between AC_VI, AC_BE and AC_BK access categories, e.g. AC_BK has the
> same throughput as AC_VI!  (any idea why?)

How did you measure throughput? What is the cw_min, cw_max and AIFS
setting for the 4 categories in your AP?

> PROBLEM 2: when I monitor the traffic I don't see any QoS control
> field in 802.11 frames. The frames are not of "QoS data" type (see
> below). It's strange that prioritization is somehow working (AC_VO has
> highest throughput, for sure), but no any QoS control fields. Is this
> possible? Do we always need a QoS control field for QoS features?
> Don't understand how I can see prioritization without QoS control
> field... 
> 
> IEEE 802.11
>    Type/Subtype: Unknown (0x14)      <------ not a "QoS data" type
>    Frame Control: 0xA045 (Normal)
>        Version: 1
>        Type: Control frame (1)
>        Subtype: 4
>        Flags: 0xA0

Did you enable CONFIG_IPW2200_QOS? You can dump more QoS related stuff
with debug=0x80000000.

Thanks,
-yi


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