FGRE: Collecting Performance Statistics

Now that you are connected to the network, you can start collecting measurements regarding the link quality. As the nodes are physically located in the same building, but in different floors and rooms, you can notice significant differences among the statistics collected from the nodes.

In order to retrieve statistics from the dongle and push them to a database server you will have to send the following command:

 
root@node044:~# wmxstat --oml-domain fgre-teamX.1 --oml-collect tcp:10.64.44.232:3003

where X is the number of your team. The statistics collected from the USB dongle are:

• The Base Station ID that the dongle is associated to
• The Received Signal Strength Indicator (RSSI)
• The Carrier to Interference plus Noise Ratio (CINR)

In the following links you can find out more on RSSI and CINR.

The server that the measurements are collected is the same that you used previously for the visualization part. You can visualize the results at that server with the following command:

ruby1.9.1 -I lib example/fgre/simple_viz_server.rb start --db fgre-teamX.1 -p 300X

and by visiting the webpage indicated.

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FGRE: Connecting to the WiMAX Network

In order to connect to the Base Station, issue the following commands:

wget --http-user admin --http-password admin -qO - "http://192.168.0.1/cgi/cli?stopSs"
wget --http-user admin --http-password admin -qO - "http://192.168.0.1/cgi/cli?addChannel frequency=2590000 bandwidth=10"
wget --http-user admin --http-password admin -qO - "http://192.168.0.1/cgi/cli?startSs"

The first one, instructs the dongle to disconnect from any network that it is attached on. The second command, instructs the dongle to use the WiMAX channel at 2590MHz with a 10MHz channel bandwidth. Finally, with the third command the dongle connects to the NITOS WiMAX network. 
You can verify that the dongle has connected by sending the following command:

 ping 192.168.55.3 

If the host responds, you are connected to the Base Station. Host 192.168.55.3 is the server behind the Base Station, responsible for configuring it and routing the traffic coming from it.

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FGRE: Experimental Topology used

The topology that we are examining in this tutorial is a central Base Station unit, able to route requests from an internal WiMAX network to the internet. The process is similar to the one that takes place in your home's wireless router;

• The Base Station is using the 192.168.55.1 IP address
• Multiple clients use the 192.168.55.0/24 subnet to communicate with the Base Station
• Packets routed through the Base Station are sent over the internet through a NAT translation

However, the devices that we currently use do not allow us to interface directly the WiMAX device. If you send the following command you will all get an output similar to the following:

 
root@node044:~# ifconfig tel0
tel0      Link encap:Ethernet  HWaddr 00:1e:42:02:18:72
          inet addr:192.168.0.8  Bcast:192.168.0.255  Mask:255.255.255.0
          inet6 addr: fe80::21e:42ff:fe02:1872/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:19939 errors:0 dropped:0 overruns:0 frame:0
          TX packets:325172 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:6477672 (6.4 MB)  TX bytes:486501878 (486.5 MB)

As you all observe, all the clients have the same IP address (192.168.0.8). This is ought to the architecture of the WiMAX stick which is like the following figure.



Since the WiMAX devices need a rather complex configuration in order to allow access to the WiMAX interfaces of another node, we have automated the procedure in a script. Once you have logged in a node, issue the following command:

root@node044:~# wmxfix

Now you will have to prepare the device to connect to the WiMAX network.

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