Working with captured packets
6.9. Time display formats and time references
While packets are captured, each packet is timestamped. These timestamps will be saved to the cap- ture file, so they will be available for later analysis.
When the packets are displayed, the presentation of these timestamps can be chosen by the user. There are four presentation formats available:
•Time of Day, e.g. 20:02:48.863096 The absolute time of the day when the packet was captured.
•Date and Time of Day, e.g.
•Seconds Since Beginning of Capture, e.g. 123.299139 The time relative to the start of the cap- ture file or the first "Time Reference" before this packet (see Section 6.9.1, “Packet time referen- cing”).
•Seconds Since Previous Packet, e.g. 1.162423 The time relative to the previous packet.
The time format can be selected from the View menu, see Figure 3.5, “The "View" Menu”.
XXX - how is the GMT / localtime thing handled.
6.9.1.Packet time referencing
The user can set time references to packets. A time reference is the starting point for all subsequent packet time calculations. It will be useful, if you want to see the time values relative to a special packet, e.g. the start of a new request. It's possible to set multiple time references in the capture file.
Warning!
The time references will not be saved permanently and will be lost when you close the capture file.
Note!
Time referencing will only be useful, if the time display format is set to "Seconds Since Beginning of Capture". If one of the other time display formats are used, time referencing will have no effect (and will make no sense either).
To work with time references, choose one of the "Time Reference" items in the "Edit" menu , see Section 3.6, “The "Edit" menu”, or from the
•Set Time Reference (toggle) Toggles the time reference state of the currently selected packet to on or off.
•Find Next Find the next time referenced packet in the "Packet List" pane.
•Find Previous Find the previous time referenced packet in the "Packet List" pane.
Figure 6.11. Ethereal showing a time referenced packet
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