[Ns-developers] Wifi management frames

[Mathieu Lacage]

On Tue, 2009-03-31 at 22:33 +0200, Mirko Banchi wrote:
> Hi all,
> 
> i have some questions about 802.11 management frames i'd like to discuss
> with you.
> 
> For now all management frames are handled in NqstaWifiMac, NqapWifiMac,
> AdhocWifiMac, QapWifiMac, QstaWifiMac objects. This type of frames are
> stored in the same queues where are stored data frames.

Outgoing beacon frames are stored in a separate queue in NqapWifiMac.

> -First question:
> 
> Should be there a specific queue for management frames ?
> What will happen if a station becomes disassociated (so a probeReq or a
> associationReq are needed) and have other packets in queue?

There should not be a separate queue for nqos MACs.

> See:
> 
> src/devices/wifi/nqsta-wifi-mac.cc
>    NqstaWifiMac::Enqueue
>    NstaWifiMac::TryToEnsureAssociated
>    NqstaWifiMac::SendProbeRequest
> 
> -Second question:
> 
> Working with block ack there is need to send action frames (management
> frames) in order to setup block ack. I think that the exchange of this
> frames between two station must be accomplished with high priority. I
> used a method

What does 802.11e say about this ? 

> WifiMacQueue::PushFront (Ptr<Packet> packet, const WifiMacHeader &hdr)
> 
> that pushes packets in queue's head but it's very horrible: the
> expiration of MsduLifeTime doesn't work :(
> 
> I think that a dedicated queue (like m_beaconDca in NqapWifiMac) could
> resolve this problems.

It could, but I wonder what the specification requires.

Mathieu