36.6 One-Way TCP Trace Dynamics

TCP packets generated by one of the one-way TCP agents and destined for a TCP sink agent passing over a traced link (see section ) will generate a trace file lines of the form:

+ 0.94176 2 3 tcp 1000 ------ 0 0.0 3.0 25 40
+ 0.94276 2 3 tcp 1000 ------ 0 0.0 3.0 26 41
d 0.94276 2 3 tcp 1000 ------ 0 0.0 3.0 26 41
+ 0.95072 2 0 ack 40 ------ 0 3.0 0.0 14 29
- 0.95072 2 0 ack 40 ------ 0 3.0 0.0 14 29
- 0.95176 2 3 tcp 1000 ------ 0 0.0 3.0 21 36
+ 0.95176 2 3 tcp 1000 ------ 0 0.0 3.0 27 42

The exact format of this trace file is given in section . When tracing TCP, packets of type tcp or ack are relevant. Their type, size, sequence number (ack number for ack packets), and arrival/depart/drop time are given by field positions 5, 6, 11, and 2, respectively. The + indicates a packet arrival, d a drop, and - a departure. A number of scripts process this file to produce graphical output or statistical summaries (see, for example, ~ns/test-suite.tcl, the finish procedure.