The problem of improving the performance and scalability of current monitoring systems, which generally follow a centralised and static management model is considered herein. Several alternative solutions based on Mobile Agents (MAS), specifically tailored to network monitoring are described. In particular, the key problem of computing efficiently the initial number and location of MAS is addressed, and techniques for rapid MA deployment are described. Mathematical models for the proposed MA solutions and for the common technique of centralised polling are built and a comparative analysis of their performance is carried out. Performance is expressed in terms of monitoring trafic and delay. Results on traffic show that MAS typically offer improved performance, although they do not always scale better than polling. However, results on delay demonstrate that MA solutions improve both scalability and performance under most circumstances.