which documents can i get something about wifi AP's packet queue

[hongyu deng]

Hi all,

I feel confused in where i can get something about wifi AP's cache. wifi-mac-queue.cc?

I want to know where AP queue locate when there are many packets arrive at the same time? And which .cc i should read to get those relevant info?

My network topology like as below:(UE works as an gateway, and i want to find out where is its cache or queue when many packets pass it).

Any answer is appreciated! Or give me a hint.      

Best,

Hong.                  

[Rediet]

Hello Hong,

You can have a look at ApWifiMac and StaWifiMac. These two classes implement RegularWifiMac in which 5 DcaTxop objects are defined: 4 for QoS related queue handling (EdcaTxopN which extends DcaTxop) and 1 for non-QoS (simple DcaTxop). These are the objects containing WifiMacQueue objects. Also note that ApWifiMac defines an additional DcaTxop exclusively for beacon handling.

Knowing this, you can find how the AP handles the packets it receives by looking into ApWifiMac::Enqueue method.

BR,

Rediet

[hongyu deng]

Hi Rediet,

Thanks you very much for your reply! It's very helpful for me.

I need sometimes to learn those codes and to come true my mind.

Thanks.

Have fun,

Hong.

[hongyu deng]

Hi again Rediet,

Do you know how to track packet path in simulation, I found in my script the topology which shown previous have problems,

when i set app like this : remoteHost_App->Setup (remoteHost_dlUdpSocket, RemoteHost2StaAddress, 1024, 10, DataRate ("0.1Mb/s")); no packet loss.

when change to : remoteHost_App->Setup (remoteHost_dlUdpSocket, RemoteHost2StaAddress, 1024, 10, DataRate ("10Mb/s")); STA can receive 6 packet till simulation stop. 

So my question is : whether the remoteHost's DataRate is too big so that the sta can not receive all packet? And whether exist a way to track packet?

Thanks,

Hong.

[Rediet]

Hello Hong,

There are different ways of tracking the packet. You can connect to WifMac trace sources like MacTxDrop to see if your missing packets have been dropped before even being transmitted to the PHY layer, or WifiPhy trace sources like PhyTxBegin to check whether the transmission has been begun. The same thing can be done on STA's side for Rx. Have a look at the full list in the Doxygen (refering to manual for how to connect trace sources). Another option can be using an IDE like Eclipse to do step by step debugging with breakpoints (but in that case do reduce the number of STAs to the minimum). You can also parse the logs... If anyone else has a better option, please do refute.

As for the application layer data rate that you chose, which 802.11 version (11b, 11n etc) and data rate selection algorithm have you used?

Rediet

[hongyu deng]

Hi Rediet,

Thanks your rapidly reply.It's very helpful.

Like you said,i used Eclipse to debug the script which contain only one sta, and use the log to see how the packet through the AP to sta.

But maybe i just start, so need more time to understand the code and the process how the packet pass.

I will try to use the trace source to get more info.

I used the IdealWifiManager : wifi.SetRemoteStationManager ("ns3::IdealWifiManager"); 

Thanks.

Have fun,

Hong.