Network Instruments Observer - Manual (Page 18)

Getting Started with Observer Modes and Tools
12 Observer® Quick Start Manual
Packet Capture
Packet Capture is the mode in which Observer records all traffic in the
segment, storing the data in RAM or on disk for examination. As useful as
statistical and cumulative summaries are—such as those provided by
Network Trending, for example—it is sometimes necessary to look closely at
network packets themselves in order to diagnose a problem.
Filtering
While it is certainly possible for Observer to capture and save all the packets
on the local segment, that’s generally undesirable; wading through all the
network traffic looking for the specific problem or issue can be a prohibitively
time-consuming and annoying task. Fortunately, most often the network
administrator will have some idea of the source of the problem—and perhaps
of the protocols involved—and can choose to filter out much of the
extraneous data.
Click Tools > Probe Filter Setup or click on the icon on the Observer
toolbar to begin configuring a filter.
Filtering is an important tool in the use of Observer, and while it can be
effectively used in many modes, it’s almost invariably useful in Packet
Capture.
Figure 6: Filtering