Outstanding Data Graph

Outstanding Data graphs (named X2Y_owin.xpl) are generated with the -N option. A sample is shown in Figure 5.11.

Figure 5.11: Outstanding Data Graph

The Y-axis represents the Outstanding Data in bytes and the X-axis represents time. The idea behind these graphs to estimate the congestion window at the sender. Since this cannot be determined accurately, we use the outstanding unacknowledged data as an estimate.

• Red Line represents instantaneous outstanding data samples at various points in the lifetime of the connection.
• Blue Line tracks the average outstanding data up to that point.
• Green Line tracks the weighted average of outstanding data up to that point, and is as explained in the calculation of the wavg owin field in Section 4.3.
• Yellow Line tracks the window advertised by the opposite end-point i.e., the receive window (rwnd).

Note: If you find that the yellow line clutters up your graph, you may turn it off with the --noshowrwinline option.