Studying the performance of the existing network provides a baseline
measurement from which to measure the performance of the new network
. Measurements of
the present network can be used to show the customer how much better the new
network performs after the design has been implemented. Any existing problems
should also be documented. If the customer tries to blame these problems on the
new installation, the documentation will be helpful.
Since the
performance of existing network segments will affect overall performance, it is
important to study the performance of the existing segments to determine how to
meet the overall network performance goals. If a network is too large to study
all segments, then analyze the segments that will interoperate the most with
the new network design. Pay particular attention to backbone networks and
networks that connect old and new areas.
In some cases, the goals of a
customer might conflict with improving network performance. For example, the
customer might want to reduce costs and not be concerned about network
performance. In this case, the documentation of the original performance will
prove that the network was not optimized to begin with, for cost reasons, and
the new design has not made the performance worse.
The analysis of an
existing network can be used to identify legacy systems that must be
incorporated into a new design. Sometimes customers are not aware of the fact
that older protocols are still running on their networks. By capturing network
traffic with a protocol analyzer as part of the baseline analysis, the
protocols running on the network can be identified without having to rely on
the knowledge of the customer.