The conceptual design and prototypical development of a performance management procedure for computer communication networks are presented. The procedure aims to improve the network performance by online adjustment of protocol parameters. The techniques of perturbation analysis in discrete-event dynamical systems, stochastic approximation, and learning automata are used in formulating the performance management procedure. The prototype procedure is evaluated on a test apparatus which consists of a number of host computers interconnected by an IEEE 802.4-based MAP network, and test results are presented and discussed. The conceptual design offers a step forward to bridging the gap between management standards and users' demands for efficient network operations, since most standards, such as ISO and IEEE standards, address only the architecture and interfaces for network management. The proposed concept of performance management can be used as an offline tool for selecting default parameter settings of a network.