Apparatus and methods facilitate customizable and extensible 
performance monitoring of a 
computer network. One method accepts a 
composite score definition in terms of N 
system variables, wherein N≧2; determines N 
raw data values, each 
raw data value corresponding to one of the N 
system variables; computes the 
composite score in accordance with the definition using the N 
raw data values as inputs; and outputs the 
composite score. The composite 
score definition is preferably in the form of a markup language, such as 
XML. The composite 
score definition preferably comprises, for each of the N 
system variables, a mapping and a weight. Preferably the composite 
score is displayed in at least one graphic form, such as a dial gauge, a bar indicator or a number, on a 
hypertext page. The 
hypertext page preferably contains one or more links to 
hypertext pages containing information regarding the scores and / or raw data values from which the composite score is derived. Another method accepts a mapping by which a raw 
data value associated with a corresponding system variable is mapped to a score, determines a raw 
data value corresponding to the system variable, converts the raw 
data value to a score in accordance with the mapping; and produces an output based on the score. One apparatus comprises a composite score definition, a 
data collector, a calculation logic and an output. The 
data collector collects a raw data value corresponding to one of the N system variables. The calculation logic is connected to the 
data collector and calculates the composite score in accordance with the definition using the N raw data values as inputs. The composite score is conveyed by way of the output. Preferably, the data collector comprises a 
database in which at least some of the raw data values are stored and a communication module by which at least some of the raw data values are transported, preferably according to the SNMP and / or the ICMP protocols. Another apparatus comprises a mapping, a data collector, a converter and an output. A raw data value associated with a corresponding system variable is mapped to a score, according to the mapping.