Traffic Control

Jouni Malinen jkmaline at
Sun Dec 15 12:28:46 EST 2002

On Thu, Dec 12, 2002 at 04:56:13PM -0000, Pedro Estrela wrote:

> a) The client to client packets on the same AP cell are sent directly to
> each other, not passing through the AP at all. It is sufficient for the
> destination STA to be in range to receive the packet.

That's not true with current IEEE 802.11 BSS mode; in IBSS that is the
case, but there is no AP in IBSS anyway. In BSS, stations send all
frames via the AP. If I remember correctly, possibility for direct
STA->STA traffic (i.e., bypassing AP) is proposed in new draft standard
(802.11e), but I do not think it is yet implemented in current wlan

> b) if option "ap_bridge_packets == 1" is set, then all received packets on
> the AP destinated to another client associated to this AP are sent directly
> to the interface on the driver, not passing through TC. this also happens
> for Layer2 broadcast and multicast packets. Howerver, currently AFAIK this
> facility is not used because point A (see above) causes all traffic to go
> _direct_ between stations.

This is used and ap_bridge_packets=1 is the default in the driver. So
yes, it is the AP code doing this bridging between two associated
stations. By setting ap_bridge_packets=0, one should get the frames
going through the Linux stack and be able to perform QoS, etc. for them.
However, this will also mean that there has to be something doing the
bridging back to the same interface (or routing without ICMP redirects,
if that is more appropriate).

Jouni Malinen                                            PGP id EFC895FA

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