User Tools

Site Tools


assignment-1

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Next revision
Previous revision
assignment-1 [2008/09/15 11:11]
shravan
assignment-1 [2008/09/15 11:12]
shravan
Line 92: Line 92:
 **Step 2:** Now create a station mode interface using the ''​wlanconfig''​ tool. (Use ''​managed''​ for wlanmode) Bring the interface up.\\ **Step 2:** Now create a station mode interface using the ''​wlanconfig''​ tool. (Use ''​managed''​ for wlanmode) Bring the interface up.\\
 **Step 3:** Set the ''​essid''​ to ''​cs707''​. At this point, for the first few seconds, when you type the ''​iwconfig''​ command multiple times, you should see the ''​Frequency:''​ parameter in ''​iwconfig''​ changing. This implies that your client is scanning different channels to lock onto the frequency of your access point. After a while when you type ''​iwconfig''​ the ''​Frequency:''​ parameter should show the same frequency on which your AP is and ''​Access Point:''​ should contain the MAC address of your AP. \\ **Step 3:** Set the ''​essid''​ to ''​cs707''​. At this point, for the first few seconds, when you type the ''​iwconfig''​ command multiple times, you should see the ''​Frequency:''​ parameter in ''​iwconfig''​ changing. This implies that your client is scanning different channels to lock onto the frequency of your access point. After a while when you type ''​iwconfig''​ the ''​Frequency:''​ parameter should show the same frequency on which your AP is and ''​Access Point:''​ should contain the MAC address of your AP. \\
-**Step 6:** Give your client an IP address : Run ''​ifconfig athX <​client-IP>''​\\+**Step 6:** Give your client an IP address : Run ''​ifconfig athX <​client-IP> ​up'' ​(e.g., client-IP can be 192.168.25.2)\\
 You can now run ''​ping''​ tests to verify that your client is indeed connected to the ''​cs707''​ AP. You can now run ''​ping''​ tests to verify that your client is indeed connected to the ''​cs707''​ AP.
  
Line 139: Line 139:
 ==== Analyzing the wireless traces ==== ==== Analyzing the wireless traces ====
  
-Your captured trace has packets sent by multiple wireless nodes. You need to first filter out the packets sent by the AP. To do that use the ''​wireshark''​ tool. For this set the filter to ''​(ip.src == AP-IP && udp)''​. Count the total number of UDP packets (''​TOTPKTS''​) sent by the AP. Now, in order to compute the wireless loss rates, find out how many of these packets have ''​retry''​ bit set in them. For this set the filter to ''​ (ip.src == AP-IP) && udp && !(wlan.fc.retry == 0) ''​ and count the number of retries (''​RETX-PKTS''​). We can now compute the wireless loss rate using ''​ RETX-PKTS/​TOT-PKTS''​+Your captured trace has packets sent by multiple wireless nodes. You need to first filter out the packets sent by the AP. To do that use the ''​wireshark''​ tool (Open using ''​wireshark <​trace-file-name>''​). For this set the filter to ''​(ip.src == AP-IP && udp)''​. Count the total number of UDP packets (''​TOTPKTS''​) sent by the AP. Now, in order to compute the wireless loss rates, find out how many of these packets have ''​retry''​ bit set in them. For this set the filter to ''​ (ip.src == AP-IP) && udp && !(wlan.fc.retry == 0) ''​ and count the number of retries (''​RETX-PKTS''​). We can now compute the wireless loss rate using ''​ RETX-PKTS/​TOT-PKTS''​
assignment-1.txt ยท Last modified: 2008/09/15 11:12 by shravan