System information

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Trending and Analysis Menu
Network Trending Mode
Network Trending Overview
Observer’s Network Trending mode, in conjunction with the Network Trending
Viewer, allows you to collect, store, view, and analyze the network traffic statistics
over long periods of time. This will provide you with baseline comparison data,
which is often essential in identifying and troubleshooting network performance
problems. Network Trending also generates text reports about network conditions
over specified time periods.
You can configure Observer to run Network Trending mode continuously or start the
Network Trending mode automatically every time you start Observer. The statistics
data is stored in a format that can be easily compressed and passed for viewing to any
site that has an Observer Network Trending Viewer installed. The Network Trending
Viewer does not collect the traffic information, it only processes the information
collected by Observer.
The task of collecting network statistics over a long period of time imposes
limitations on the ways data can be collected and stored. Protocol analyzers can
provide many types of information, and often it is difficult to know in advance what
data will be needed to find the cause of an existing problem or to diagnose a
developing one.
Ideally, it would be best to collect all of the data passing through the network and then
go through the data back and forth with some kind of analysis tool and view the
processed data from different perspectives. Unfortunately, the volume of data passing
through a typical network is usually very high. The huge amount of data generated by
capturing every packet over long periods of time would not be practical to store and
analyze given a typical PC’s disk and processor resources.
Protocol analyzers deal with this problem using a mechanism called “sampling.” The
term “sampling” refers to a method of collecting only some portion of the total data
flowing on a network at any one moment and statistically adjusting the results for this
as a representation of the total data sent on the network. This may mean that a
protocol analyzer, through sampling, may process only one packet in every ten. The
number “10” in this case is called a sampling divider. Since the protocol analyzer can
keep up with the processing of every tenth packet in high and low traffic conditions, it