[[mscom_lab2]]

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mscom_lab2 [2016/04/27 16:13]
beckmanf [Using Netem for modelling latency and packet loss on the channel] Kein Leerzeichen bei ms
mscom_lab2 [2016/05/02 20:46] (current)
beckmanf Moved Bridge setup
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 </​code>​ </​code>​
  
-Now start the server ​on the lab pc and the client on your laptop. Test the tftp connection by transferring "​hallo.txt"​ from the client to the server. Run wireshark on the client and on the server to observe the packets which are transferred. Sketch a message sequence chart. ​+Now start the server ​one of the laptops ​and the client on the other laptop. Test the tftp connection by transferring "​hallo.txt"​ from the client to the server. Run wireshark on the client and on the server to observe the packets which are transferred. Sketch a message sequence chart. ​
  
  
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   - Transfer the file and compare the measurement data with your calculation. ​   - Transfer the file and compare the measurement data with your calculation. ​
  
-Modify the ethernet speed to 10 MBit/s and measure again. Set the ethernet speed back to 100MBit/s after the measurement. ​+Modify the ethernet speed to 10 MBit/s and measure again. Set the ethernet speed back to 100MBit/s after the measurement
 + 
 + 
 +==== Bridge Setup ==== 
 + 
 +The lab pc will be used a network emulation device for the connection between the two laptops. Configure the lab pc with the two network cards as bridge. Connect the two laptops directly to the lab pc. 
 + 
 +<​code>​ 
 +sudo brctl addbr mybridge 
 +sudo brctl addif mybridge eth1 
 +sudo brctl show 
 +sudo brctl addif mybridge eth2 
 +sudo ifconfig eth1 0.0.0.0 
 +sudo ifconfig eth2 0.0.0.0 
 +sudo ifconfig mybridge up 
 +</​code>​ 
 + 
 +The bridge should now be up and running. Test the connection between the two laptops with ping and measure the RTT. Do the tftp transfer test again - now the software bridge between the two laptops. 
 + 
 +All further modifications regarding latency and packet loss should be done on the lab pc and not on the laptops. The reason is that wireshark will tap the traffic after the netem traffic control module.
  
 ==== Using Netem for modelling latency and packet loss on the channel ==== ==== Using Netem for modelling latency and packet loss on the channel ====
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   - The first flow should end while the second flow is still running. ​   - The first flow should end while the second flow is still running. ​
   - Produce a graph with cwnd and ssthr showing the dynamic adaption of the rate   - Produce a graph with cwnd and ssthr showing the dynamic adaption of the rate
- 
- 
- 
-==== Bridge Setup ==== 
- 
-Configure the lab pc on the top shelf with the two network cards as bridge. ​ 
- 
-<​code>​ 
-sudo brctl addbr mybridge 
-sudo brctl addif mybridge eth1 
-sudo brctl show 
-sudo brctl addif mybridge eth2 
-sudo ifconfig eth1 0.0.0.0 
-sudo ifconfig eth2 0.0.0.0 
-sudo ifconfig mybridge up 
-</​code>​ 
- 
-The bridge should now be up and running. Cable the pc as bridge between lab pc and laptop and test the connection. ​ 
  
  
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