In global grid computing, i.e. Wide Area Network (WAN) grid computing, Grid network services allow grid users or the programming environment to monitor the status of network resources and to reallocate them. Specifically, the Network Information and Monitoring Service (NIMS) provides up to date information on the grid network status.

In this study two implementations of a specific NIMS component, i.e. the topology discovery service (TDS), are presented. The first implementation features a centralized broker that produces information for the consumers/users. In the second one, users are contemporarily producers and consumers of the required information. Both implementations are applicable to networks based on commercial routers without requiring any router protocol modification.