The Challenges of Developing a Baseline of Network
Performance
Developing an accurate baseline of the network performance
is not an easy task. One challenging aspect is determining how much time is
required to perform the analysis. It is important to allocate multiple days to
ensure an accurate baseline. If measurements are made over too short of a
timeframe, temporary errors may appear to be more significant than they are.
In addition to allocating sufficient time for a baseline analysis, it is
also important to establish a time period during which to perform the analysis.
A baseline of normal performance should not include unusual problems caused by
exceptionally large traffic loads. For example, end of the quarter sales
processing may put an abnormal load on a company network. In a retail
environment, network traffic can increase five times around certain holidays.
Network traffic to a web server can unexpectedly increase as much as ten times
if the website gets linked to other popular sites or is listed in search
engines.
In general, errors, packet loss, cell loss, and latency
increase with network load. To obtain a meaningful measurement of typical
accuracy and delay, do the baseline analysis during periods of normal traffic
load. However, if the main goal of the customer is to improve performance
during peak load, then be sure to study performance during peak load. The
decision of whether to measure normal performance, performance during peak
load, or both, depends on the goals of the network design.
Some
customers do not recognize the value of studying the existing network before
designing and implementing enhancements. The expectations of the customer for a
speedy design proposal might make it difficult to take the time to develop a
baseline of performance on the existing network. Also, the other job tasks and
goals of an SE might make it impractical to spend days developing a precise
baseline.
A good understanding of the technical and business goals of
the customer can be helpful in determining how thorough the study should be.
Discussions with the customer on business goals can help identify important
segments to study, which carry critical and backbone traffic. Ask the customer
to help identify typical segments from which to draw conclusions about other
segments.