Scalability is a many-sided property which can be captured in a scalability metric that balances cost, volume, timeliness and other attirbutes of value in the system, as a function of its size. Studies of typical metrics can reveal which parts of the agent infrastructure are most critical for scalability. Simple metrics are investigated for systems dominated by agent behaviour. As a system is scaled up, the length of the average tour increases and this has a major effect on performance and scalability limits. Senstivity experiments show that infrastructure improvements can improve scalability but they will not alter the general conclusion. Keywords Agents, mobility, performance, scalability, scalability metric, itinerary
C. Murray Woodside