When conducting the initial baseline, start by selecting a few variables
that represent the defined policies. If too many data points are selected, the
amount of data can be overwhelming, making analysis of the collected data
difficult. Start out simply and fine tune along the way. Generally, some good
starting measures are interface utilization
and CPU
utilization.

Collect data for a day or two before starting the actual baseline study to
determine whether the right data is being gathered from the right devices. Then
graph the collected data in different ways to better show where the network
needs improvement. Slicing through the data in different ways can reveal
interesting and sometimes surprising observations.
Baseline analysis of
the network should be conducted on a regular basis. Perform an annual analysis
of the entire network or baseline different sections of the network on a
rotating basis. Analysis must be conducted regularly in order to understand how
the network is affected by growth and other changes.
Gathering the information in a consistent manner and analyzing the data will
allow informed design decisions as well as expedite fault isolation.