A distributed, hierarchical information service for computer networks might rely in several instances, located in different layers. A distributed directory service, for example, might be comprised of upper level listings, and local directories. The upper level listings contain a compact version of the local directories. Clients desiring to access the information contained in local directories might first access the high-level listings, in order to locate the appropriate local instance. One of the keys for the competent operation of such service is the ability of properly summarizing the information, which will be maintained in the upper level directories. We analyze the case of the Lookup Service in the Information Services plane of perfSONAR performance monitoring distributed architecture, which implements IPv4 summarization in its functions. We propose an empirical method, or heuristic, to achieve the summarizations, based on the PATRICIA tree. We further apply the heuristic on a simulated distributed test bed and contemplate the results.