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= 802.11 Reference Design: Dual-Node Log Capture Example = 

This example of the Experiments Framework uses two WARP v3 nodes, one configured as an AP, the other as a STA.  The log_capture_two_node_two_flow.py will capture a log of LTG traffic flows between the AP and STA and write the data to an HDF5 log file for later processing.  This example demonstrates how to:
 * Control two WARP v3 nodes from one wlan_exp script
 * Use the wlan_exp framework Local Traffic Generator (LTG) to create traffic
 * Capture an HDF5 log file from the data logged by each node

The flow of the log_capture_two_node_two_flow.py script is:
 1. Initialize two WARP v3 nodes
 1. Ensure nodes are configured as one AP, one STA and that the STA is associated with AP
 1. Start a fully-backlogged locally generated traffic (LTG) flow from AP -> STA
 1. Wait 30 seconds
 1. Start a fully-backlogged locally generated traffic (LTG) flow from STA -> AP
 1. Wait 30 seconds
 1. Stop the locally generated traffic (LTG) flow from STA -> AP
 1. Wait 30 seconds
 1. Stop the locally generated traffic (LTG) flow from AP -> AP
 1. Read the log data from each node and write an HDF5 log file

To run this example:
 * Setup wlan_exp (see [wiki:../../GettingStarted Getting Started] for details)
 * Configure two WARP v3 nodes with the 802.11 Reference Design bitstream- one AP, one STA
 * Open the file in a text editor and change the {{{NODE_SERIAL_LIST}}} to match your serial numbers
 * Open a Python shell
 * CD to the '''Python_Reference/examples/log''' directory from the expanded 802.11 Reference design archive
 * Run {{{python log_capture_two_node_two_flow.py}}}

The script will run for 2 minutes, then display its results:
{{{
Initializing experiment

Reseting the network config for all nodes on subnet 10.0.0.
Initializing W3-a-00006 as Node 0
Initializing W3-a-00183 as Node 1
Initializing the time of all nodes on 10.0.0 to: 0.0

Experimental Setup:
Adding current time to log for nodes on 10.0.0

Run Experiment:

Start LTG - AP -> STA

Start LTG - STA -> AP

Stop  LTG - STA -> AP

Stop  LTG - AP -> STA

Log Sizes:  AP  = 19,258,096 bytes
            STA = 32,143,640 bytes

Writing Log Files...
    ap_two_node_two_flow_capture.hdf5
    sta_two_node_two_flow_capture.hdf5
Done.
}}}


NOTE:  By default, the script uses the log file names defined by the variables AP_HDF5_FILENAME and STA_HDF5_FILENAME.  If you would like different file names, please modify the variables accordingly.  These files will be written to your current directory.

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'''Source:''' the script is included in the 802.11 Reference Design archive at '''Python_Reference/examples/log/log_capture_two_node_two_flow.py'''.