Re: WiFi handover between two APs + Ping STA-Server in the background

[Alex Latorre]

Do you have the final code? I would be very thankful if you can share it.

Thank you so much!

Alex.

El jueves, 3 de septiembre de 2015, 23:30:31 (UTC+2), Lukasz Siemiaszko escribió:

Ok,
Problem solved by applying static routing. Also, I put each AP into different subnet, thus I dynamically assign IPv4 address to STA after association with an AP (only update default gateway into STA's routing table).

Thank you all for your support.

W dniu niedziela, 30 sierpnia 2015 19:06:25 UTC+2 użytkownik Lukasz Siemiaszko napisał:

Hi everyone,

I am working on WiFi handover with the Ping in the background. I saw several topics on the ns-3-users group, however I could not find answers for my problems.
The idea of my simulation is to programiticaly populate the surface with muliple APs and STAs. Then, each STA pings the Server node. Thus, all APs are connected to the Server node S via common node C - I call it "Connector" (since each P2P link has to belong to different subnet, I added node C before the Server in order to ping single IPv4).

                      +------+                          
                      |Server|                          
                      |Node S|                          
                      +------+                          
                           |0                          
                           |   P2P                      
                           |   10.200.0.0/24            
                           |0                          
                      +---------+                      
P2P                   |Connector|          P2P          
10.100.0.0/24+--------+Node C   +------+   10.100.1.0/24
             |       1+---------+2     |                
             |0                        |0              
        +------------+        +------------+            
        |Access Point|        |Access Point|            
        |Node AP1    |        |Node AP2    |            
        +-----X------+        +------X-----+            
              X1                      1                
              X       WiFi           X                  
              X       10.0.0.0/24                      
              X                      X                  
        +-----X------+                                  
        |WiFi Station|               X                  
        |Node STA1   +---------->                      
        +------------+               X                  

So far I wrote almost whole simulation script. It works fine for the single AP and multiple STAs. However, after adding extra APs, the simulation crashes: assert failed. cond="m_ecmpRootExits.size () <= 1", msg="Assumed there is at most one exit from the root to this vertex", file=../src/internet/model/global-route-manager-impl.cc. This is understandable, since both ends of the 'tree' point to the same network (10.0.0.0/24).
I tried to put APs in the different subnets, but I have no idea how to do that (I get: aborted. cond="!(networkHere == networkThere)", msg="GlobalRouter::ProcessSingleBroadcastLink(): Network number confusion", file=../src/internet/model/global-router-interface.cc, line=844"). Also, how to assign IPv4 address for STA after association with an AP?

Please find attached my simplified script for manual simulation with 2 APs and 1 STA.

Best regards,
Lukasz